Comparison of synthesis of 15 alpha-hydroxylated steroids in males of four North American lamprey species (original) (raw)
Related papers
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2003
The main purpose of the study was to identify the principal gonadal steroids synthesized by male and female sea lampreys, Petromyzon marinus. To achieve this, we used high performance liquid chromatography to separate the steroids in the serum of sexually mature animals, and to separate the steroids produced by gonadal tissue incubated in the presence of radiolabelled precursor steroids, as a means of identifying the major steroidogenic pathways. We were unable to detect evidence of the 'classical' steroids, such as 17b-estradiol (E ) or testosterone (T) in the serum of either male 2 or female lampreys. Instead, the principal chromatographic peaks contained very polar compounds that had elution times consistent with 15a-hydroxylated estrogens and androgens, and there were sex-specific differences in the chemical nature and the quantity of these compounds. Testis fragments or ovarian follicles co-incubated with tritium-labelled pregnenolone (w HxP ), 17-hydroxyprogesterone (w Hx17OHP ), or androstenedione (w HxA ), provided additional confirmation that 3 3 3 5 4 4
General and Comparative Endocrinology, 2004
The sea lamprey (Petromyzon marinus L.) represents one of the two most ancient classes of vertebrates and possesses a functional hypothalamus-pituitary-gonadal axis. However, the presence and functionality of androgens in the sea lamprey remain elusive. Recently, 15a-hydroxytestosterone (15a-T) has been found in sea lamprey gonads and blood plasma. In this study we examined changes of circulatory concentrations of 15a-T in response to gonadotropin releasing hormone (GnRH) treatments. Plasma concentrations of 15a-T in sea lamprey increased 2-5 times for all GnRH-injected sea lamprey compared to controls (P < 0:0001). However, there were no differences among responses: (1) to the two forms of GnRH (lamprey GnRH I or lamprey GnRH III), (2) to the doses delivered (50, 100, or 200 lg/kg), or (3) between post-injection sample intervals (8 or 24 h). Between lampreys from the Atlantic Ocean and Great Lakes sites, two of seven GnRH form and dosage comparisons showed between-site differences, but were not believed to represent an overall between-site difference. These are the first data to show a response of a C19 steroid to GnRH stimulation in sea lamprey.
Sex steroids and their receptors in lampreys
Steroids, 2008
The use of steroids and their receptors as ligand-gated transcription factors is thought to be an important step in vertebrate evolution. The lamprey is the earliest-evolving vertebrate to date in which sex steroids and their receptors have been demonstrated to have hormonal roles similar to those found in jawed vertebrates. Sex steroids and their receptors have been examined in several lamprey species, and the majority of studies have focused on the sea lamprey, Petromyzon marinus. While classical steroids appear to be present in lampreys, their function, concentrations, and synthesis have not been determined conclusively. The only classical steroid that is thought to act as a hormone in both males and females is estradiol. Recent research has established that lampreys produce and circulate 15alpha-hydroxylated steroids, and that these steroids respond to upstream stimulation within the hypothalamic-pituitary-gonadal axis. In particular, 15alpha-hydroxyprogesterone is highly sensitive and responds in great magnitude to stimulation, and is likely a hormone. Lampreys also appear to use androstenedione, a precursor to vertebrate androgens, as their main androgen, and a receptor for androstenedione has recently been described. Non-classical steroids are prevalent in many aquatic vertebrates, and the non-classical steroids found in the sea lamprey may represent an evolutionary artifact, or alternatively may be a way to avoid endocrine disruption when ingesting the body fluids of host fish. The lamprey will continue to be an interesting model for examining the evolution of steroid hormones, steroid receptors, and steroid function.
15α-Hydroxyprogesterone in male sea lampreys, Petromyzon marinus L
Steroids, 2004
There is growing evidence that sea lampreys, Petromyzon marinus L., produce gonadal steroids differing from those of other vertebrates by possessing an additional hydroxyl group at the C15 position. Here we demonstrate that sea lamprey testes produce 15α-hydroxyprogesterone (15α-P) in vitro when incubated with tritiated progesterone, that 15α-P is present in the plasma of sea lampreys, and that plasma concentrations
General and Comparative Endocrinology, 1983
Hydroxysteroid dehydrogenase (HSD) activity was determined spectrophotometrically on homogenates of the pronephros, the opisthonephros, and the gonads of metamorphosing, immature, and mature adult male and female brook lampreys (Lampetra planeri Bloch), employing pregnenolone, dehydroepiandrosterone, androsterone, epiandrosterone, and 3@,17@dihydroxy-Sol-androstane as substrates and NAD or NADP as coenzymes in October, December, February, and April. With NADP a higher HSD activity was observed in the majority of the assays. In larval brook lampreys a NAD-dependent HSD activity was detected in presumed adrenocortical tissue (PAT) homogenates with pregnenolone and 3p,17pdihydroxy-So-androstane and in gonad homogenates only with 3&17@-dihydroxy-Sol-androstane. With 3p,17@-dihydroxy-Soi-androstane as substrate the highest enzyme activities were measured in PAT and gonad, homogenates from animals of all investigated life stages. A varying intensity of HSD activity in the examined tissue homogenates probably dependent on stages of the individual development was observed.
An anti-steroidogenic inhibitory primer pheromone in male sea lamprey (Petromyzon marinus)
General and comparative endocrinology, 2013
Reproductive functions can be modulated by both stimulatory and inhibitory primer pheromones released by conspecifics. Many stimulatory primer pheromones have been documented, but relatively few inhibitory primer pheromones have been reported in vertebrates. The sea lamprey male sex pheromone system presents an advantageous model to explore the stimulatory and inhibitory primer pheromone functions in vertebrates since several pheromone components have been identified. We hypothesized that a candidate sex pheromone component, 7a, 12a-dihydroxy-5a-cholan-3-one-24-oic acid (3 keto-allocholic acid or 3kACA), exerts priming effects through the hypothalamic-pituitary-gonadal (HPG) axis. To test this hypothesis, we measured the peptide concentrations and gene expressions of lamprey gonadotropin releasing hormones (lGnRH) and the HPG output in immature male sea lamprey exposed to waterborne 3kACA. Exposure to waterborne 3kACA altered neuronal activation markers such as jun and jun N-terminal kinase (JNK), and lGnRH mRNA levels in the brain. Waterborne 3kACA also increased lGnRH-III, but not lGnRH-I or -II, in the forebrain. In the plasma, 3kACA exposure decreased all three lGnRH peptide concentrations after 1 h exposure. After 2 h exposure, 3kACA increased lGnRH-I and -III, but decreased lGnRH-II peptide concentrations in the plasma. Plasma lGnRH peptide concentrations showed differential phasic patterns. Group housing condition appeared to increase the averaged plasma lGnRH levels in male sea lamprey compared to isolated males. Interestingly, 15a-hydroxyprogesterone (15a-P) concentrations decreased after prolonged 3kACA exposure (at least 24 h). To our knowledge, this is the only known synthetic vertebrate pheromone component that inhibits steroidogenesis in males.
caspian journal of environmental sciences, 2017
The objective of this study was to determine the effect of human chorionic gonadotropin (hCG) on sexual maturation, plasma sex steroids (17β-estradiol, E2 and 17α-hydroxy progesterone (17α OHP)) and thyroid hormones (triiodothyronine, T3 and thyroxin, T4) levels in upstream - migrating Caspian lamprey. During the experiment, 36 fish (24 females and 12 males) in spring 2013 and 36 fish (24 females and 12 males) in fall 2013 were collected from the Shirud River estuary in Mazandaran Province, the Southern Caspian Sea during their upstream migration to the freshwater. All fish were injected with hCG at the doses of 1000, 1500 and 2000 IU.kg BW-1. The injection was a two - step process (50% of hormone in each step) by 12 h interval. After the first injection, fish were retained in the cages in the river beds and 24 hours after the second injection, fish were checked for egg and sperm release after mild abdomen pressure. Blood samples were taken for determining sex steroid levels. Resu...
2013
Maturing degree-days, gonadal histology, and changes in serum sex steroids (progesterone, P; testosterone, T; and 17b-estradiol, E2) were examined in maturing and mature spring migrant Caspian lamprey Caspiomyzon wagneri (Kessler, 1870) in the Shirud River (southern Caspian Sea). Blood and gonad samples were collected from ten fish when they first entered the river (maturing stage) and from ten fish that showed spawning readiness after being held in cages in the river (mature stage). The maturing degree-days of Caspian lamprey from the start of upstream migration to maturation was 208–470C.day. Serum P and E2 concentrations in maturing females were significantly higher than in maturing males, but in the mature stage, serum P and E2 concentrations of females were lower than males. In both stages, there were no differences in serum concentration of T between females and males. In both males and females, P increased significantly with maturation; T levels likewise appeared to increase, but the difference was not significant. E2 increased significantly with maturation in males, but females showed a significant decrease. Maturing females had similar stage gonads with the germinal vesicle in the polar position. Maturing males had testes that primarily contained secondary spermatocytes with an occasional occurrence of spermatozoa. These results suggest that males mature earlier than females, which is a pattern similar to that found in the sea lamprey.
Sex steroid hormones are important players in the control of sex differentiation by regulating gonadal development in teleosts. Although estrogens are clearly associated with the ovarian differentiation in teleosts, the effects of androgens on early gonadal development are still a matter of debate. Traditionally, 11-ketotestosterone (11-KT) is considered themajor androgen in fish; however, 5α-dihydrotestosterone (5α-DHT), themost potent androgen in tetrapods, was recently found in fish testis and plasma, but its physiological role is still unknown. In this context, the expression of genes associatedwith steroidogenesis and spermatogenesis, body growth and sex differentiation were assessed in Odontesthes bonariensis larvae fed with food supplemented with two doses of 5α-DHT (0.1 and 10 μg/g of food) from hatching to 6 weeks of age. At the lowest dose, 5α-DHT treated larvae showed an estrogenic gene expression pattern, with lowhsd11b2 and high cyp19a1a and er2 expression levelswith no differences in sex ratio. At the highest dose, 5α-DHT produced a male-shifted sex ratio and the larvae exhibited a gene expression profile characteristic of an advancement of spermatogenesis, with inhibition of amh and stimulation of ndrg3. No differences were observed in somatic growth. These results suggest that in this species, 5α-DHT could have a role on sex differentiation and its effects can differ according to the dose.
General and Comparative Endocrinology, 2001
The sea bream (Sparus aurata) is a protandrous hermaphrodite teleost fish in which estrogen administration induces testicular regression without influencing ovarian development. To analyze the changes in steroidogenesis of fish treated with two levels of estrogen (2 and 10 mg ⅐ kg ؊1 ) and untreated control fish, fragments of gonads were incubated with tritiated 17-hydroxyprogesterone and the metabolites identified. The ability to extract radioactivity decreased with incubation time and was lower in gonads containing a larger proportion of ovarian tissue. The difference in steroidogenic capacity between control and estrogen-treated groups was generally quantitative rather than qualitative and paralleled the observed histological changes. The same metabolites were identified in all three groups, but estrogen treatment caused a marked inhibition of 5-reduction, 3␣-reduction, side-chain cleavage, and 11-hydroxylation. The main androgens identified were 11-hydroxy-4-androstene-3,17-dione and 3␣-hydroxy-5-androstane-3,17dione, and the synthesis of both steroids was inhibited by estrogen treatment. Of the more polar pregnanes, 5pregnane-3␣,17,20␣-triol and 5-pregnane-3␣,17,20triol were detected in significant amounts, but only the latter appeared to be associated with development of the testis (in the untreated fish). A feature of sea bream gonadal steroidogenesis less common in other teleosts was the presence of 6␣-and 6-hydroxylation.