Effects of Highly Diluted Sucussed Thyroxine on Metamorphosis of Highland Frogs (original) (raw)

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Abstract

These experiments, performed in Graz and in Utrecht, investigate the influence of extremely dilute thyroxine in a special "homeopathic" preparation on two transitions in the metamorphosis of highland amphibia: a) from the 2-legged to the 4-legged stage; b) from the tailed 4-legged stage to the untailed stage, the juvenile frog (performed in the two laboratories in Graz) or to the stage with reduced tail, respectively (performed in Utrecht).

Key takeaways

sparkles

Highly diluted thyroxine (solution T4.30X) slows metamorphosis of highland frogs, contrasting with pharmacological thyroxine effects.
Experiments revealed significant statistical differences between T4.30X and control (H2O.30X) treatments.
Two key metamorphic transitions were studied: from 2-legged to 4-legged and from tailed to tailless stages.
Over 500 tadpoles (n=549) were observed, with experiments conducted in Graz and Utrecht laboratories.
Future research should include various dilution levels and additional controls for comprehensive analysis.

Climbing activity in frogs and the effect of highly diluted succussed thyroxine

British Homoeopathic journal, 1991

SummaryThe experiments investigate the influence of extremely dilute thyroxine (T4) in special ‘homœopathic’ preparation (dilution T4.30x) on the spontaneous tendency of juvenile frogs to leave the water and climb on land. Climbing activity was suppressed by dilution T4.30x, with statistical significance both in comparison to the effect of the ‘potentized’ preparation of the solvent (dilution H2O.30x) as well as in comparison to the control observations before the start of the treatment. Finally, in the search for optimal treatment duration, it was shown that exposure to the dilutions for even a few minutes sufficed to cause significant effects.

The Effect of Ultra-high Dilutions of Thyroxine on the Morphogenesis of Xenopus laevis Tadpoles

Alternative & Integrative Medicine, 2018

Background: The morphogenesis of Xenopus laevis is dependent on the thyroid system and the production of thyroxine. Numerous studies using the amphibian model have shown tadpoles to be responsive to ultra-high dilutions of Thyoxine. Ultra-high dilutions used in Homeopathy are not suitable to pharmacokinetic investigation due to their lack of detectable active ingredient and the lack of analytical methods with sufficient sensitivity; however, laboratory and clinical studies are providing experimental evidence contributing to the pharmacodynamics of high dilution remedies. Method: The experiment consisted of four groups, labelled according to the dilution each group was administered, Control (no treatment), Thyroxine 6C, Thyroxine 30C and Thyroxine 200C. Each group consisted of 90 tadpoles divided into three tanks of 30 tadpoles each. The respective dilutions were administered to the water the tadpoles were housed in every eight hours from Day 32 until Day 58 of the experiment. Tail length was measured every three days from Day 32 to Day 48 and every day from Day 48 to Day 58. Results: Thyroxine 6C was shown to have had a stimulatory effect while Thyroxine 30C had an inhibitory effect on the growth phase of the Xenopus laevis tadpole tail. Thyroxine 6C, 30C and 200C were shown to have had an inhibitory effect on the reduction phase of the Xenopus laevis tadpole tail. Conclusion: Where the results were shown to have had a stimulatory effect on the growth phase of the Xenopus laevis tadpole tail, it was likely due to a physiological effect, mimicking the action of the naturally circulating thyroxine. The results that were shown to have had an inhibitory effect are in line with the "Law of Similars" and the fact that a homeopathic preparation of Thyroxine would have an opposing effect to that of naturally circulating thyroxine.

Evaluation of the amphibian metamorphosis assay: Exposure to the goitrogen methimazole and the endogenous thyroid hormone L-thyroxine

Environmental Toxicology and Chemistry, 2010

The U.S. Environmental Protection Agency (U.S. EPA) has included an amphibian metamorphosis assay (AMA) to detect thyroid active chemicals in Tier 1 testing of their endocrine screening program. To understand the variability, specificity, and reliability of the key endpoints of this assay, two exposure studies with Xenopus laevis tadpoles were conducted with two known thyroid-active compounds, namely, methimazole or L-thyroxine, for a total of 21 d. In addition, various increased-flow-rate treatments were included in the exposures to evaluate the effects of physical stress on metamorphic development. The endpoints examined in the exposures were wet weight, snout-vent length, hind-limb length, developmental stage, and thyroid and gonadal histopathology. As expected, the results indicated that both methimazole and L-thyroxine were thyroid active in the AMA, hind-limb length and thyroid histopathology being the most sensitive endpoints of thyroid activity. Tadpoles that were exposed to the various physical stressors in these experiments showed no signs of altered metamorphic development, and exposure to the thyroid-active compounds had no effect on the developing gonad of X. laevis. Taken together, these results support the use of the AMA as a Tier 1 endocrine screen for detection of potential thyroid pathway activity; however, the lack of a true negative response (no-effect) during the validation process prevents a full evaluation of this assay's specificity at this time.

DOSE AND STAGE SPECIFIC EFFECTS OF THYROXINE ON THE TADPOLES OF DUTTAPHRYNUS MELANOSTICTUS (ANURA: BUFONIDAE

International Journal of Pharmacy and Pharmaceutical Sciences, 2015

Objective: Aim of the study was to investigate the effects of thyroxine on the pre metamorphic tadpoles of the common Asian toad, Duttaphrynus melanostictus (Anura: Bufonidae), an ideal model for understanding the role of thyroxine during vertebrate development. Methods: Tadpoles of two developmental stages, i.e., Gosner stege 30 and 34 was exposed to 50, 100 and 200 ng/ml of thyroxine by adding the hormone to the tadpole rearing water. Toxic and teratogenic effects of thyroxine on the tadpoles were recorded. Besides, effects of thyroxine on specific activity of acid phosphatase, a lysosomal marker enzyme in the tails of the tadpoles were investigated. Results: A Dose and stage specific toxic effect of the hormone was observed in the treated tadpoles. There was precocious metamorphosis with incomplete differentiation of limbs, deformities of body and tail in the treated tadpoles. Biochemical investigation of tails showed a dose specific elevation in the specific activity of acid phosphatase up to 2.5 fold in 50 ng/ml and 3.15 fold in 100 ng/ml treated tadpoles as compared to corresponding control tadpoles. Conclusion: Thus, the hormone thyroxine exhibited toxic as well as teratogenic effects on the developing tadpoles and also led to dose dependent elevation in specific activity of acid phosphatase in vivo in their tails.

Lingg et al. Int J High Dilution Research, 2011, Raw Data Highland Amphibians 1990-2010

2011

Experiments on amphibian metamorphosis can vary considerably in duration. The authors had set themselves the task of defining a generally applicable pooling method for metamorphosis experiments. The problem of artificial differences in variability when comparing and pooling data from several experiments was approached by normalization with respect to time based on the development of both test and the control animals. The range from 0% to 100% over which the fraction of four-legged animals progresses in the course of an experiment is divided into 10%intervals and the 10% reference points are mapped on a corresponding scale. Each measurement is then assigned to the point on the time scale to which it is closest. In this way each reference point is assigned a value giving the number or percentage of four-legged animals at that point on the scale. Subsequent analysis was then based on the individual values for the test and control groups that corresponded to the joint 10% reference point. Normalization respect to time was done on the assumption that differences in metamorphosis speed attributable to treatment would override differences in duration between experiments. The results of experiments performed over the course of two decades (1990 -2010) on highland Rana temporaria treated with a homeopathically prepared high dilution of thyroxine ("30x") are presented in full detail based on this normalization method. Differences found between treatment groups thus calculated were in line with those obtained with other pooling methods. Thyroxine 30x does slow down metamorphosis in inert highland amphibians. This was observed by five researchers in 20 subexperiments, and it seems to be the most reliable bio-assay found in amphibian research on homeopathy so far. When experiments were performed with highland animals pretreated by hyperstimulation with molecular thyroxine, slowing down of metamorphosis was again observed (by three out of four researchers) in most of 10 sub-experiments.

The influence of acclimation temperature on the metabolic response of frog tissue to thyroxine administered in vivo

General and Comparative Endocrinology, 1975

Leopard frogs (Rana pipiens complex) were given daily injections of Na-I-thyroxine (2.0 &lo g body wt) in the dorsal lymph sac, while control animals were given daily injections of equivalent volumes of the alkaline vehicle. Half of the animals were acclimated in darkness at a constant temperature of W, whereas the remaining frogs were acclimated in darkness at 25". At the end of 5.5 days of treatment, the frogs were sacrificed; and oxygen consumption of liver tissue from each animal was measured by differential respirometry at the temperature to which the donor was acclimated. Oxygen consumption of liver tissue from hyperthyroid frogs acclimated at 25" was 21% higher than it was in preparations from control animals acclimated at the same temperature. However, oxygen uptake by liver preparations from hyperthyroid frogs acclimated at 15" did not differ significantly from control levels. Thus, in anuran amphibians-as in reptilian ectotherms-temperature seems to govern the metabolic response of tissues to thyroid hormones.

Conversion of thyroxine to triiodothyronine in an adult amphibian, Bufo marinus

General and Comparative Endocrinology, 1981

... Article Outline. References. GENERAL AND COMPARATIVE ENDOCRINOLOGY 43, 1719 (1981) Conversion of Thyroxine to Triiodothyronine in an Adult Amphibian, Bufo marinus CLARK T. SAWIN,* JANICE L. BOLAFFI,f ... Braverman, LE, Ingbar, SH, and Sterling, K. (1970). ...

Amphibian metamorphosis as a model for studying the developmental actions of thyroid hormone

Biochimie, 1999

The thyroid hormones L-thyroxine and triiodo-L-thyronine have profound effects on postembryonic development of most vertebrates. Analysis of their action in mammals is vitiated by the exposure of the developing foetus to a number of maternal factors which do not allow one to specifically define the role of thyroid hormone (TH) or that of other hormones and factors that modulate its action. Amphibian metamorphosis is obligatorily dependent on TH which can initiate all the diverse physiological manifestations of this postembryonic developmental process (morphogenesis, cell death, re-structuring, etc.) in free-living embryos and larvae of most anurans. This article will first describe the salient features of metamorphosis and its control by TH and other hormones. Emphasis will be laid on the key role played by TH receptor (TR), in particular the phenomenon of TR gene autoinduction, in initiating the developmental action of TH. Finally, it will be argued that the findings on the control of amphibian metamorphosis enhance our understanding of the regulation of postembryonic development by TH in other vertebrate species. © Société française de biochimie et biologie moléculaire / Elsevier, Paris thyroid hormone / metamorphosis / postembryonic development / thyroid hormone receptor / autoinduction

Effects of developmental and growth history on metamorphosis in the gray treefrog,Hyla versicolor (Amphibia, Anura)

Journal of Experimental Zoology, 1999

In ecological models, the timing of amphibian metamorphosis is dependent upon rate of larval growth, e.g., tadpoles that experience a decrease in growth rate can initiate metamorphosis early. Recent authors have suggested that this plasticity may be lost at some point during the larval period. We tested this hypothesis by exposing groups of tadpoles of the gray treefrog, Hyla versicolor, to different growth schedules. In endocrine models, metamorphosis is dependent on thyroxine levels and thyroxine is antagonized by prolactin (amphibian larval growth hormone), consistent with the idea that a rapidly growing tadpole can delay metamorphosis. Thus, we also manipulated the rate of development by supplementing or maintaining natural thyroxine levels for half of the tadpoles in each growth treatment. All tadpoles that received thyroxine supplements metamorphosed at the same time regardless of growth history. They also metamorphosed earlier than tadpoles not treated with thyroxine. Tadpoles not given thyroxine supplements metamorphosed at different times: those growing rapidly during day 15-34 metamorphosed earlier than tadpoles growing slowly. Growth rate before day 15 and after day 34 had no effect on metamorphic timing. The difference in larval period between these rapidly growing tadpoles and their sisters given thyroxine treatments was less than the same comparison for tadpoles that grew slowly during the same period. This apparent prolactin/thyroxine antagonism did not exist after day 34. These results are consistent with the hypothesis of a loss of plasticity in metamorphic timing.

Inhibition of thyroxine-induced metamorphosis by prolactin in tadpoles, Rana catesbeiana

Endocrinologia japonica, 1979

Thyroxine (T4)-prolactin interactions on hepatic arginase and ornithine transcarbamylase (OTC) as well as hind legs, tail, digestive tract and median eminence were investigated in tadpoles, Rana catesbeiana. Prolactin completely blocked T4-induced tail resorption, but failed to suppress hind-leg growth, shortening of digestive tract and promotion by T4 of the median eminence development. Prolactin blocked T4-induced increase in hepatic arginase activity but not in hepatic OTC activity. A possibility that T4 and prolactin are regulating the hepatic arginase indirectly is discussed.

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References (39)

delGiudice, E., Preparata, G., Vitellio, G.: 5. Water äs a Free Electric Dipole Laser. Physical Review Leiters 61: 1085-1088, 1988
Resch, G., Gutmann, V.: Wissenschaftliche Grundlagen der Homöopathie. O.-Verlag, 6. Berg/Starnbergersee, Germany, 1986
Popp, F.-A.: Some Elements of 7. Homoeopathy. British Homoeopathic Jour- nal 79 (No.3): 161-166, 1990
Popp, F.-A. (ed.): Electromagnetic Bio-Infor- mation -2nd Edition. Urban & Schwarzen- berg, München, 1989
van Wijk, R., Wiegant, F.A.: Homoeopathic Remedies and Pressure-induced Changes in the Galvanic Resistance of the Skin. State University, Utrecht, 1989
Smith, C.W., Best, S.: Electromagnetic Man. Dent Publishing, London, 1989
Endler, P.C., Pongratz, W., Haidvogl, M., et al.: Climbing Activity of Frogs and the Effect of Highly Diluted Succussed Thyroxine. British Homoeopathic Journal (accepted for publication)
Rubik, B.: Homeopathy and Coherent Exci- tation in Living Systems. The Berlin Journal on Research in Homoeopathy 1 (No.l): 24- 27,1990 Benveniste, J.: Personal Communication. Baden-Baden, Oct 1990
Endler, P.: Aspects of Information Storage and Structures in Water. British Homoeo- pathic Journal78: 253-254, 1989
Weingärtner, O.: NMR Features that Relate to Homoeopathic Sulphur Potencies. Berlin Journal on Research in Homoeopathy 1 (No 1): 61-68, 1990
Luu-Dang-Vinh, C.: Les dilutions homeo- pathiques controle et etude par spectrographie Raman-laser -Thesis. University de Montpellier, 1974
Ludwig,W.: Eigenresonanzenverschiedener Wasserformen. Erfahrungsheilkunde 36 (No.13):, 1987
King, G.: Experimental Investigations for the Purpose of Scientifical Proving of the Efficacy of Homoeopathic Preparations -A Literature Review about Publications from English-speaking Countries -Thesis.
Tierärtzliche Hochschule, Hannover, 1988
Righetti, M.: Forschung in der Homeopathic -Wissenschaftliche Grundlagen, Problematik und Ergebnisse. Burgdorf Publisher, Göttingen, 1988
Haidvogl, M.: Naturwissenschaftliche Grundlagen der Homoopathie. DerKinderarzt 21: 75-84, 1990
Boyd, W. E.: Biochemical and Biological Evidence of the Activity of High Potencies. British Homoeopathic Journal 44:7-44,1954
Poitevin, B.: Scientific Bases of Homoeo- pathy. The Berlin Journal on Research in Homoeopathy 1 (No.l): 46-60, 1990
Haslund,T.: Homeopathic Plant Experiments. The Berlin Journal on Research in Homoeo- pathy 1 (No.3): , 1991
Endler, P.C., Pongratz, W.: Homeopathic Effect of a Plant Hormone? -Preliminary Report. The Berlin Journal on Research in Homoeopathy 1 (No.3): , 1991
Hornung, J.: Publications on Controlled Clinical Trials in Homoeopathy -A Bibliography on 22 Medical Studies. The Berlin Journal on Research in Homoeopathy l(No.l): 16-18, 1990
Lapp, C., Wurmser, L., Ney, J.: Mobilisation de 1'Arsenic fixe chez le cobaye sous l'influ- ence de doses infinitesimales d'arseniate. Therapie 13: 46-55, 1958
Bildet, J.: Etude de Faction de differentes dilutions home'opathiques de Phosphorus blanc (Phosphorus) sur 1'hepatite toxique du rat -These Pharmacie. University de Bordeaux, Bordeaux II, 1975
Souza Magro, I.A., et al.: Redufao da nefro- toxidade induzida por aminoglucosideos. Proceedings of the Congress of the Liga Medicorum Homoeopathica Internationalis 41 (Rio de Janeiro): , 1986
Cazin, J. C., Cazin, M., Gaborit, J. L., Chaoui, A., Boiron, J., Belon, P., Cherruault, Y., Papapanayotou, C.: A Study of the Effect of Decimal and Centesimal Dilutions of Arsenic on the Retention and Mobilization of Arsenic in the Rat. Human Toxicology 6: 315-320, 1987
Fisher, P., House, I., Belon, P., Turner, P.: The Influence of the Homoeopathic Remedy Plumbum metallicum on the Excretion Kinetics of Lead in Rats. Human Toxicology 6: 321-324, 1987
Harisch, G., Kretschmer, M.: Jenseits vom Milligramm -Die Biochemie auf den Spuren der Homoopathie. Springer, Berlin, 1990
Davenas, E., Poitevin, B., Benveniste, J.: Effect on Mouse Peritoneal Macrophages of Orally Administered Very High Dilutions of Silica. European Journal of Pharmacology 135:313-319, 1987
Bastide, M., Daurat, V., Doucet-Jaboeuf, M., Pelegrin, A., Dorfman, P.: Immunomodulator Activity of Very Low Doses of Thymulin in Mice. International Journal of Immunotherapy m (No.3): 191-200, 1987
König, K.: Über die Wirkung extrem ver- dünnter ("homöopathischer") Metallsalz- lösungen auf Entwicklung und Wachstum von Kaulquappen. Zeitschrift fürdiegesamte experimentelle Medizin 56: 581-593, 1927
Vondracek, V.: Die Sterblichkeit der Kaulquappen in Ultralösungen -quoted from Coulter, 1981. Zeitschrift fiir die gesamte experimentelle Medizin 66: 535-538, 1929
Herkovits, J., Perez-Coll, C.: Potentized Microdoses of Cadmium Reduce the Lethal Effect of this Heavy Metal in Amphibian Embryos. The Berlin Journal on Research in Homoeopathy 1 (No.2): 93-97, 1991
Wehner, R., Gehring, W.: Zoologie. Thieme, Stuttgart, 1990
Ganong, W.F.: Lehrbuch der Medizinischen Physiologie. Springer, Berlin, 1974
Giersberg, H.: Hormone. Springer, Berlin, 1972
Clark, J.H.: Dictionary of Materia Medica - 3. ed.. Health Master, Health Science Press, Safron Walden, 1987
Gosner,K.L.: A Simplified Table for Staging Anuran Embryos and Larvae with Notes on Identification. Herpetologica 16: 183-190, 1960
Homöopathisches Arzneibuch -1. Ausgabe. Deutscher Apothekerverlag, Stuttgart and Govi Verlag, Frankfurt, 1978
Hintze, J.: Number of Cruncher Statistical Systems -Survival Analysis -Version 5.5. Kaysville, Utah, 1988

Effects of Highly Diluted Succussed Thyroxine on Metamorphosis of Highland Frogs

2003

Treatment of highland frogs from the two-legged stage with homeopathically prepared thyroxin (10-11 - 10-21)

TheScientificWorldJournal, 2008

The influence of moderately diluted, agitated, i.e., homeopathically prepared, thyroxin solutions (10 -11 -10 -21 , final concentration in the basin water 0.6 × 10 -15 -0.6 × 10 -25 parts by weight after the first application) on metamorphosis in highland Rana temporaria from the two-legged stage was studied. In accordance with the homeopathic idea of effects of specially prepared dilutions being inverse to those of their mother substances, animals were treated either with thyroxin 10 -11 -10 -21 or analogously prepared blank solution (water). Development was monitored by documenting the number of animals that had entered the four-legged stage. It has been found that animals treated with the thyroxin solutions metamorphosed more slowly than the control animals, i.e., the effect of the homeopathically prepared thyroxin was opposed to the usual effect of molecular thyroxin. The number of test animals that reached the four-legged stage at defined points in time was smaller (2-13.5%) in the group treated with homeopathically prepared thyroxin at the points in time, compared to control. The results in this study sustain the previous multiresearcher findings that show that diluted homeopathically prepared thyroxin is able to slow down metamorphosis of R. temporaria.

Treatment of lowland frogs from the spawn stage with homeopathically prepared thyroxin (10-30)

TheScientificWorldJournal, 2007

The influence of a highly diluted agitated, i.e. homeopathically prepared thyroxin solution (10 -30 , final concentration in the basin water 10 -35 parts by weight after the first application) on metamorphosis in lowland Rana temporaria from the spawn stage on was studied. The treatment with homeopathically prepared thyroxin solution (10 -30 ) starts at the frogspawn stage. It represents a tool to learn more about the previously standardized amphibian model, where the thyroxin solution was applied from the two-legged stage on only. Lowland frogs were pretreated by immersing spawn in an aqueous molecular thyroxin dilution (10 -8 parts by weight). In later stages of development (2 to 4 legged), this has been found to speed up metamorphosis by around 15%. In accordance with the homeopathic idea of detoxication or cure, hyperstimulated animals (spawn or, in subsequence, larvae) were treated either with thyroxin that had been highly diluted and agitated in successive steps, i.e. homeopathically prepared (10 -30 ), or analogously prepared blank solution (water). Development was monitored by documenting the number of animals that had entered the four-legged stage. It has been found that animals treated with the test solution metamorphosed more slowly than the control animals, i.e. the effect of the homeopathically prepared thyroxin was opposed to the usual effect of molecular thyroxin. The number of test animals that reached the 4-legged stage at defined points in time was slightly smaller in the group treated with homeopathically prepared thyroxin at some, but not at all points in time, compared to control. The results in this study sustain the previous multi researcher findings that highly diluted homeopathically prepared thyroxin is able to slow down metamorphosis of Rana temporaria KEY WORDS: amphibian, hormone, thyroxin, homeopathic dilution, curative effect Graunke et al: Treatment of Lowland Frogs TheScientificWorldJOURNAL (2007) 7, xxx-xxx

EFFECT OF THYROXINE ON THE MORPHOMETRIC STUDIES OF TOAD, BUFO STOMATICUS

The present study deals with the effect of thyroxine on the young toads of Bufo stomaticus. The Toads were exposed to two different doses of thyroxine i.e. 10-2 thyroxine and 10-4 thyroxine. Experiment was conducted for 15 days. The young toads were examine for various morphometric parameters viz:-Snout to Vent Length (SVL), Head Length (HL), Head Width (HW), Diameter of Eye (DOE), Inter Orbital Space (IOS), Hand Length (HAL), Foot Length (FL), Tibea Length (TL), Leg length (LL), Arm Length (AL), First Finger Length (FFL) and Second Finger length (SFL).The results were statistically analyzed and significant changes were observed on the selected parameters.

The impact of the goitrogen 6-propylthiouracil (PTU) on West-African clawed frog (Xenopus tropicalis) exposed during metamorphosis

Aquatic Toxicology, 2007

This study investigated the suitability of using tadpoles of the West-African clawed frog (Xenopus tropicalis) for studying adverse effects on the thyroid hormone system after chemical exposure. Tadpoles were exposed to the thyroxine synthesis inhibitor 6-propylthiouracil (PTU) at concentrations between 2-75 mg/L during 14 days. After 5 and 14 days of exposure the developmental stage, hind limb length, body length and weight were measured. Moreover, histological measurements of the thyroid glands were performed after 14 days of exposure. These measurements included maximum thyroid cross-section area, follicular area and epithelial cell height. Tadpoles in the 75 mg/L treatment were less developed and had shorter hind limb length than the control group after 14 days of exposure. No effects were recorded on these parameters at lower PTU concentrations. The histological measurements revealed clear dose-response relationships in both follicular cross-section area and epithelial cell height, with lowest observed effect concentrations (LOECs) recorded at 2 and 5 mg/L, respectively. This study shows that X. tropicalis is a suitable species for detection of thyroid disrupting chemicals. Further, histopathological measurements of thyroid glands are more sensitive parameters compared with apical endpoints when studying adverse effects on thyroid hormone system caused by PTU exposure in X. tropicalis.

The effect of homeopathically prepared thyroxine on highland frogs: influence of electromagnetic fields

Homeopathy, 2008

Background: Previous experiments show that amphibian larvae are responsive to homeopathically prepared thyroxine. Methods: We studied the effect of a highly diluted and agitated thyroxine solution exposed to various electromagnetic fields on metamorphosis in highland Rana temporaria. The devices tested were: microwave oven, mobile phone, airport X-ray, and a red light barcode scanner. Animals were treated either with homeopathically prepared thyroxine (10 À30 parts by weight, 10 À35 in the water in which the animals were kept), or analogously prepared blank solution, or analogously prepared thyroxine exposed to the electromagnetic field of one of the devices tested. Solutions were administered at 48 h intervals according to a standardized protocol. Results: Animals treated with the standard test solution thyroxine 10 À30 metamorphosed more slowly than the control animals, ie the effect of the homeopathically prepared thyroxine was opposed to the usual physiological effect of molecular thyroxine. The cumulative number of test animals that had reached the four-legged stage at defined points in time was smaller in the group treated with homeopathically prepared thyroxine at most of the points in time. This was found independently by all three research teams involved. In contrast, this effect did not occur when the thyroxine solution had been exposed to the field of the early model microwave oven, or mobile phone. There was no difference between aqueous or alcoholic solutions were used, and there was, if any, only a small protective effect from aluminum foil. Airport X-ray and red light barcode scanning did not diminish the effect of the homeopathic solution. Homeopathy (2008) 97, 3-9.

Triclosan exposure alters postembryonic development in a Pacific tree frog (Pseudacris regilla) Amphibian Metamorphosis Assay (TREEMA)

Aquatic Toxicology, 2013

The Amphibian Metamorphosis Assay (AMA), developed for Xenopus laevis, is designed to identify chemicals that disrupt thyroid hormone (TH)-mediated biological processes. We adapted the AMA for use on an ecologically-relevant North American species, the Pacific tree frog (Pseudacris regilla), and applied molecular endpoints to evaluate the effects of the antibacterial agent, triclosan (TCS). Premetamorphic (Gosner stage 26-28) tadpoles were immersed for 21 days in solvent control, 1.5 g/L thyroxine (T 4 ), 0.3, 3 and 30 g/L (nominal) TCS, or combined T 4 /TCS treatments. Exposure effects were scored by morphometric (developmental stage, wet weight, and body, snout-vent and hindlimb lengths) and molecular (mRNA abundance using quantitative real time polymerase chain reaction) criteria. T 4 treatment alone accelerated development concomitant with altered levels of TH receptors ␣ and ␤, proliferating cell nuclear antigen, and gelatinase B mRNAs in the brain and tail. We observed TCS-induced perturbations in all of the molecular and morphological endpoints indicating that TCS exposure disrupts coordination of postembryonic tadpole development. Clear alterations in molecular endpoints were evident at day 2 whereas the earliest morphological effects appeared at day 4 and were most evident at day 21. Although TCS alone (3 and 30 g/L) was protective against tadpole mortality, this protection was lost in the presence of T 4 . The Pacific tree frog is the most sensitive species examined to date displaying disruption of TH-mediated development by a common antimicrobial agent.

Metamorphic rate in Rana pipiens larvae treated with thyroxine or prolactin at different times in the light/dark cycle

General and Comparative Endocrinology, 1986

Rana pipiens tadpoles at Stages V to VIIK on a 12Li12D cycle with photoperiod from 0800 to 2000 hr were treated with 30 pg/liter thyroxine (T4) by immersion for various daily 8-hr spans, or by daily intraperitoneal injection at different times with 0.1 to 10 bg T, or 10 Kg prolactin (PRL), in order to see if the rate of metamorphosis varied with the time of hormone treatment. T, was most effective in promoting tail resorption and hindlimb growth and development if tadpoles were immersed at least partly in the light or if the hormone was injected late in the dark or in the early or mid light phase. T4 was least effective in accelerating metamorphosis when immersion was totally in the dark or injection early in the dark. PRL antagonized metamorphosis just as well at any time of the day except that tail fin growth was faster when PRL was administered earty in the dark. The findings show circadian vacations in target tissue responsiveness to exogenous T4 that depend on the occurrence of light during T, immersion or following T, injection. The data 'suggest rhythmicity in the secretion of endogenous T4 in the tadpole and a diurnal eff&t on T, utilization by target cells. 0 1986 Academic Press. Inc.

Effects of Highly Diluted Sucussed Thyroxine on Metamorphosis of Highland Frogs (original) (raw)

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