albert carrasco | Universidad de Concepción (original) (raw)

Papers by albert carrasco

Frontiers in Veterinary Science, Sep 7, 2023

Theriogenology, 2019

This study used a comparative approach to gather clinical information to assess the effect of bov... more This study used a comparative approach to gather clinical information to assess the effect of bovine somatotropin (bST) on follicular dynamics and ovulation in sheep and goats during an interovulatory cycle. The performance of general markers of ovarian function and specific features of follicular dynamics obtained by daily ultrasonography (US) were used to assess the hypothesis that bST, associated with supraphysiological levels of IGF-I, was able to disrupt the follicular dynamics and ovulation in Highlander ewes and Saanen goats. In Exp 1, 15 ewes and 14 goats were estrous-synchronized (P 4 -6 days þ PGFa d-6) and then allocated to a bST-treated group (50 and 100 mg, Lactotropin ® ; n ¼ 5 females each) and to an untreated control group (5 ewes and 4 goats) to assess the activity of bST through plasma IGF-I (RIA). In Exp 2, 12 animals from each species were synchronized. At day 6, they were divided into a bST-group (100 mg in sheep and 50 mg in goats, n ¼ 6 each) and an untreated control group (n ¼ 6 each). Starting at day 6 and up to 22 days after ovulation in sheep and 25 days in goats, each female was subjected to daily US (10 mHz probe) to assess follicular and luteal (CL) dynamics and ovulation. This included assessments of both general ovarian features and specific follicular wave features. Our results showed that bST increased plasma IGF-I by day 3 (p < 0.01) when compared to the control group. Moreover, these concentrations were maintained for at least 10 days in sheep and 10 days in goats before returning to pre-treatment concentrations. Increases in IGF-I after bST doses were similar in terms of a daily and total amount (P > 0.10). Results from Exp.2 indicate that in sheep, bST administration had a subtle inhibitory effect on follicular function. However, bST in goats had a stronger influence, extending the interovulatory cycle (P ¼ 0,034), increasing the number of follicular waves during the period (P ¼ 0.003), and reducing the functional potential of large follicles as measured by their lower follicular diameter (P ¼ 0.02), duration of the follicle waves (P ¼ 0.02), and persistence of follicles after reaching their maximum diameters (P ¼ 0.04). In addition, untreated sheep and goats shared common patterns of terminal follicular development and ovulations characterized by overlapping between follicular waves and ovulations of follicles from different waves, features not seen in cattle.

Chilean journal of agricultural & animal science, Dec 31, 2022

Animals

The neurotrophin beta-nerve growth factor (NGF), which is present in the semen of different mamma... more The neurotrophin beta-nerve growth factor (NGF), which is present in the semen of different mammals, elicits potent ovulatory and luteotrophic actions in llamas following systemic administration. Here, we determine if purified NGF given intramuscularly (IM) during the preovulatory stage affects the corpus luteum (CL), hormone production, endometrial gene expression, and pregnancy rate of dairy heifers. Holstein-Friesian heifers were estrus-synchronized using estradiol benzoate (EB) plus an intravaginal progesterone (P4) device (DIB). After eight days, the device was removed and cloprostenol was given IM; the next day (day 9), heifers received EB IM plus one of the following: (i) 1 mg of NGF (NGF D9 group), (ii) 1 mg of NGF 32 h after EB (NGF D10 group), or (iii) phosphate buffer saline (control group). To measure pregnancy rates, heifers were treated similarly, then artificially inseminated with sexed semen 48–52 h after DIB removal, then an ultrasound was conducted 30 days after in...

Animals, Sep 3, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Domestic Animal Endocrinology, 2017

The male gonadal tissue can be a sensitive target to the reprogramming effects of testosterone (T... more The male gonadal tissue can be a sensitive target to the reprogramming effects of testosterone (T) during prenatal development. We have demonstrated that male lambs born to dams receiving T during pregnancy-a model system to the polycystic ovary syndrome (PCOS)-show a decreased number of germ cells early in life, and when adult, a reduced amount of sperm and ejaculate volume. These findings are key to put attention to the male offspring of women bearing PCOS, as they are exposed to increased levels of androgen during pregnancy which can reprogram their reproductive outcome. A possible origin of these defects can be a disruption in the expression of the Antimüllerian hormone (AMH), due to its critical role in gonadal function at many postnatal stages, hence, prior to puberty. Therefore, we addressed the impact of prenatal T excess on the expression of AMH and factors related to its expression like AP2, SOX9, FSHR and AR in the testicular tissue through realtime PCR during the peripubertal age. We also analyzed the testicular morphology and quantified the number of Sertoli cells and germ cells in order to evaluate any further defect in the testicle. Experiments were performed in rams at 24 wk of age, hence, prior puberty. The experimental animals (T-males) consisted of rams born to mothers receiving 30 mg testosterone twice a week from day 30 to 90 of pregnancy and then increased to 40 mg until day 120 of pregnancy. The control males (C-males) were born to mothers receiving the vehicle of the hormone. We found a significant increase in the expression of the mRNA of AMH and SOX9, but not of the AP2, FHSR nor AR, in the T-males. Moreover, T-males showed a dramatic decrease in the number of germ cells, together with a decrease in the weight of their testicles. The findings of the present study show that prior to puberty, T-males are manifesting clear signs of disruption in the gonadal functions probably due to an alteration in the expression pattern of the AMH gene. The precise way by which T reprograms the expression of AMH gene remains to be established.

Endocrine, 2013

The reprograming effects of prenatal testosterone (T) treatment on postnatal reproductive paramet... more The reprograming effects of prenatal testosterone (T) treatment on postnatal reproductive parameters have been studied extensively in females of several species but similar studies in males are limited. We recently found that prenatal T treatment increases Sertoli cell number and reduced spermatogenesis in adult rams. If such disruptions are manifested early in life and involve changes in testicular paracrine environment remain to be explored. This study addresses the impact of prenatal T excess on testicular parameters in infant males, including Sertoli cell number and expression of critical genes [FSH receptor (FSHR), androgen receptor (AR), transforming growth factor beta 1 (TGFB1), 3 (TGFB3), transforming growth factor beta type 1 receptor, (TGFBR1), and anti-Müllerian hormone (AMH)] modulating testicular function. At 4 week of age, male lambs born to dams treated with 30 mg of T propionate twice weekly from day 30 to 90, followed by 40 mg of T propionate from day 90 to 120 of pregnancy (T-males), had a higher number of Sertoli cells/ testis (P = 0.035) than control males (C-males) born to dams treated with the vehicle. While no differences were observed in the expression of FSHR and TGFB3, testicular TGFBR1 expression was found to be lower in T-males (P = 0.03) compared to C-males. Expression level of AMH, TGFB1, and AR also tended to be lower in T-males. These findings provide evidence that impact of fetal exposure to T excess is evident early in postnatal life, mainly characterized by an increase in Sertoli cell number. This could explain the testicular dysfunction observed in adult rams.

Journal of Developmental Origins of Health and Disease

In animal models, exposure to excess testosterone during gestation induces polycystic ovary syndr... more In animal models, exposure to excess testosterone during gestation induces polycystic ovary syndrome (PCOS)-like reproductive and metabolic traits in female offspring, suggesting that the hyperandrogenemic intrauterine environment may have a role in the etiology of PCOS. Additionally, few studies have also addressed metabolic and reproductive outcomes in male offspring. In the present study, the intravenous glucose tolerance test (IGTT) was used to assess the insulin–glucose homeostasis at various ages during sexual development in male sheep born to testosterone-treated ewes. To further analyze the programming effect of testosterone on insulin–glucose homeostasis, indexes of insulin sensitivity were assessed in orchidectomized post-pubertal males born to testosterone-treated ewes (Torq-males) and orchidectomized post-puberal controls (Corq-males) before and 48 h after a testosterone injection. There was no difference in insulin sensitivity indexes between males born to testosterone-...

Scientific Reports

Hyperandrogenemia and metabolic disturbances during postnatal life are strongly linked both to po... more Hyperandrogenemia and metabolic disturbances during postnatal life are strongly linked both to polycystic ovary syndrome and other conditions that arise from prenatal exposure to androgen excess. In an animal model of this condition, we reported that insulin sensitivity (IS) was lower in young female sheep born to testosterone-treated mothers versus sheep born to non-exposed mothers (control). This lower insulin sensitivity remains throughout reproductive life. However, it is unknown whether abnormal postnatal levels of testosterone (T) further decrease IS derived from prenatal exposure to testosterone. Therefore, we assessed the effects of an acute testosterone administration (40 mg) on IS and insulin secretion during an intravenous glucose tolerance test performed at 40 weeks of age (adulthood) in previously ovariectomized sheep at 26 weeks of age (prepuberty), that were either prenatally exposed to testosterone (T-females, n = 6) or not (C-females, n = 6). The incremental area un...

The Journal of Maternal-Fetal & Neonatal Medicine

The administration of testosterone to pregnant sheep to resemble fetal programming of the polycys... more The administration of testosterone to pregnant sheep to resemble fetal programming of the polycystic ovary syndrome could alter other hormones/factors of maternal origin with known effects on fetal growth. Hence, we studied the weekly profile of insulin, progesterone and glucose during a treatment with testosterone propionate given biweekly from weeks 5 to 17 of pregnancy (term at 21 weeks) and checked the outcome of their fetuses at 17 weeks of gestation after C-section. Control dams were only exposed to the vehicle of the hormone. The testosterone administration did not cause any significant change in the maternal weekly profile of insulin, progesterone or glucose concentration, although the plasma levels of testosterone in the treated dams were inversely correlated to the levels of progesterone. Testosterone treatment also induced an inverse correlation between mean maternal insulin levels and fetal insulin levels; however, the fetal zoometric parameters, body weight, or insulin levels did not differ between exposed and not exposed fetuses. Therefore, treatment with testosterone during pregnancy does not cause significant impact on insulin levels in the mother, leading to less effect on the programming of fetal growth.

The Endocrine Society's 93rd Annual Meeting & Expo, June 4–7, 2011 - Boston, 2011

Endocrine Abstracts, 2016

Fetal insulin plasma levels were similar between groups. No difference was observed in fetal weig... more Fetal insulin plasma levels were similar between groups. No difference was observed in fetal weight at 120 days gestation between groups.

[ Research paper thumbnail of Rojas-García PP, Recabarren MP, Sir-Petermann T, Rey R, Palma S, Carrasco A, Perez-Marin CC, Padmanabhan V, Recabarren SE. 2012. Altered testicular development as a consequence of increase number of sertoli cell in male lambs exposed prenatally to excess testosterone. . Endocrine. Oct 18. [Epub a...](https://a.academia-assets.com/images/blank-paper.jpg)

Archivos de medicina veterinaria, 2014

Morfometría ovárica y expresión del ARN mensajero de hormona antimülleriana (AMH), receptor de FS... more Morfometría ovárica y expresión del ARN mensajero de hormona antimülleriana (AMH), receptor de FSH (FSHR) y factor nuclear kappa B (NFkB) en folículos en crecimiento de borregas expuestas prenatalmente a testosterona # Ovarian morphometry and mRNA expression of antimüllerian hormone (AMH), follicle stimulating hormone receptor (FSHR) and nuclear factor kappa B (NFkB) in growing follicles of female lambs prenatally exposed to testosterone.

Archivos de Medicina Veterinaria

Endocrine Abstracts, 2013