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PubMed1994

A cell-specific nuclear receptor is essential for adrenal and gonadal development and sexual differentiation.

Studies in adrenocortical cells have implicated the orphan nuclear receptor SF-1 in the gene regulation of the steroid hydroxylases. We used targeted disruption of the Ftz-F1 gene, which encodes SF-1, to examine its role in intact mice. Despite normal survival in utero, all Ftz-F1 null animals died by postnatal day 8; these animals lacked adrenal glands and gonads and were severely deficient in corticosterone, supporting adrenocortical insufficiency as the probable cause of death. Male and female Ftz-F1 null mice had female internal genitalia, despite complete gonadal agenesis. These studies establish that the Ftz-F1 gene is essential for sexual differentiation and formation of the primary steroidogenic tissues.

Adrenal Glands↗
PubMed2006

Comparative proteomic analysis to study molecular events during gonad development in mice.

Sex determination represents a critical bifurcation in the road of embryonic development. It is based on a finely regulated network of gene activity, as well as protein-protein interactions and activation or silencing of signaling pathways. Despite the identification of a number of critical genes, many aspects of the molecular cascade that drives the differentiation of the embryonic gonad into either a testis or an ovary remain poorly understood. To identify new proteins involved in this cascade, we employed two-dimensional gel electrophoresis and mass spectrometry to compare the protein expression profiles of fetal mouse testes and ovaries. Three proteins, hnRPA1, TRA1, and HSC71, were found to be expressed in a male-specific manner and this expression was confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) and in situ hybridization. Moreover, HSC71 was found to be hyperphosphorylated in male compared to female gonads, emphasizing the advantage of the proteomic approach in allowing the detection of posttranslational modifications.

Animals↗
PubMed2004

Alterations to gonadal development and reproductive success in Japanese medaka (Oryzias latipes) exposed to 17alpha-ethinylestradiol.

The Japanese medaka (Oryzias latipes) was used as an in vivo model to evaluate the effects of exposure to the synthetic estrogen 17alpha-ethinylestradiol (EE2) on reproductive behavior and reproductive success in fish. Exposures to EE2 began within 2 to 5 d posthatch and continued until medaka were sexually mature, between four and six months of age. Among male and female medaka exposed to EE2 at nominal concentrations of 0.2 and 2 ng/L, mating behavior and reproductive success were normal in reproductive trials. However, reproductive behavior (i.e., copulations) was suppressed in the treatment with 10 ng/L EE2. Among 19 males exposed to 10 ng/L EE2 and placed with unexposed females in reproductive trials, 16 males did not copulate and reproductive success was very low. None of the females exposed to 10 ng/L of EE2 participated in reproductive behavior with unexposed males. The reproductive trials in combination with a histological survey indicated that male fish with gonadal intersex (i.e., testis-ova) were still capable of reproductive behavior and could fertilize eggs. Even though females exposed to 10 ng/L EE2 had poor reproductive success, their ovaries showed normal development and oogenesis. These data are relevant to observations of intersex in feral fish populations. Although intersex in male fish may be an indicator of exposure to estrogenic compounds, it appears that the presence of oocytes in testicular tissue may not directly impact the reproductive capability of the male fish. However, it is clear that concentrations of endocrine disrupting chemicals (EDCs) that cause gonadal intersex are sufficient to reduce reproductive performance.

Animals↗
PubMed1998

Seasonal variation and effects of age, food availability, size, gonadal development, and parasitism on the hemogram of mytilus galloprovincialis

The study of hemogram characteristics in a population of cultured mussels through a period of 18 months revealed that the concentration of circulating Mytilus galloprovincialis hemocytes varied, following a seasonal pattern, being positively correlated with water temperature. Most mussels had between 1 and 5 x 10(6) hemocytes/ml of hemolymph. Differential counts showed that M. galloprovincialis hemolymph contained more granulocytes than hyalinocytes. The hemolymph cell concentration was not associated with size or weight of mussels. Circulating hemocyte concentration did not decrease in mussels with reabsorbing gonad, despite the hemocytic accumulation inside and around gonad follicles. No significant difference in hemolymph cell concentration was found between two groups of mussels of different ages. Nevertheless, older mussels had higher mean values of circulating granulocytes although these differences were only significant in the winter sample. Infestation by the protistan Marteilia refringens caused a significant increase of hemocytes in the hemolymph. In addition, the occurrence of some parasites induced significant changes in the proportion of circulating hemocyte types. Results suggested that a hemocytic response was detected in hemolymph when the foreign organisms are pathogenic and evoke a heavy inflammatory reaction. Mussels with large or numerous granulocytomas had a higher number of circulating granulocytes and hyalinocytes than those without granulocytomas. Copyright 1998 Academic Press.

Journal Article↗
PubMed1983

Plasma prolactin and gonadotrophins during gonadal development and the onset of photorefractoriness in male and female starlings (Sturnus vulgaris) on artificial photoperiods.

Previous studies have shown that an increase in prolactin secretion coincides with the beginning of the photorefractory phase in starlings (Sturnus vulgaris). To determine how closely this increase is associated with the onset of refractoriness, we kept starlings on photoperiods which would induce refractoriness at different rates. Four groups of males and females were transferred from 8h light:16h darkness (8L:16D) to either 18L:6D, 13L:11D, 11L:13D or 8L:16D. Weekly blood samples were assayed for LH, FSH and prolactin and the males were frequently laparotomized to determine testis volume. In males, both 18L and 13L induced marked increases in plasma gonadotrophin levels and rapid gonadal maturation. A photoperiod of 18L induced an earlier onset of refractoriness (2-4 weeks) than 13L (6 weeks). In both cases prolactin levels began to increase immediately before the onset of refractoriness. Males on 11L showed a slight increase in gonadotrophin levels and slow gonadal maturation. There was no increase in prolactin levels and these birds did not become refractory. Hormonal data from the females were similar to those from males. These results confirm that increased prolactin secretion is associated, in some way, with the onset of photorefractoriness in this species, although whether it is a cause or consequence of photorefractoriness, or simply of gonadal regression, remains unclear.

Animals↗
PubMed1989

Formation of male and female sex cords in gonadal development of C57BL/6 mouse.

The sex cords of male and female fetal C57BL/6 mice were studied by light and transmission electron microscopy to elucidate the origins of Sertoli cells (male) and follicle cells (female) in detail. In the testes of fetal mice from day 12 to day 14 post coitum (p.c.), PAS-positive substances were detected exclusively throughout the cytoplasm of Sertoli cells. On day 12 p.c., pre-Sertoli cells, identified by PAS-reaction, formed irregular and cord-like arrangements around germ cells. The arrangements were not associated with the coelomic epithelium. Thus, it is suggested that Sertoli cells are originated from the mesonephric tissues. In the ovaries, germ cell cords were still not observed at a stage immediately following the gonadal sex differentiation in male. On about day 15 p.c., connective tissues including many capillaries penetrated into the ovaries, resulting in obvious formation of germ cell cord-like arrangements. At the same time, the coelomic epithelium-derived cells (CEd cells) as well as the mesonephros-derived cells (Md cells) invaded the adjacent arrangements. It is concluded that the follicle cells are originated most from Md cells and some from CEd cells.

Animals↗
PubMed2000

Sex-related differences in the effects of late winter pairing activity and seasonal influences on neuroendocrinology and gonadal development of mallards.

The importance of late winter pairing activity on the neuroendocrinology of wild waterfowl is unknown. In this study, we examined the sex-related differences in the roles of late winter pairing activity and seasonal influences on neuroendocrine and reproductive physiology in both male and female mallards. Our main goals were to determine (1) which physiological responses were influenced by pairing status or by seasonal changes and (2) whether responses differed between the sexes. Thus, physiological responses of mallards in different pairing status categories were assessed at two times: January 28 to February 5 and February 24 to March 3. Ducks were assigned to one of the following pairing status categories: strong pairs, temporary pairs, unpaired or lone birds within the flock, or birds isolated in same-sex groups. Seasonal changes correlated with increases in both gonadal mass and hypothalamic content of vasoactive intestinal peptide in both sexes, whereas only pairing status correlated with changes in body mass in both sexes. The main sex-related differences were the following: (1) Seasonal decreases in hypothalamic gonadotrophin releasing hormone II content occurred only in females. (2) Seasonal increases in serum prolactin occurred only in males, whereas levels in females were low throughout the study. (3) Both male and female gonadal masses increased seasonally, but male gonadal mass was initially twice that of females. (4) Body mass of both sexes was influenced by pairing status correlations (i.e., all paired or lone birds were heavier than isolated birds), but body mass in males decreased seasonally. No sex-related differences occurred in hypothalamic gonadotrophin releasing hormone I content or circulating serum luteinizing hormone. Taken together, these results indicate that seasonal reproduction in mallards is regulated not only by seasonal but also by social cues, and differences occur between the sexes, months in advance of actual breeding.

Animals↗
PubMed1975

Effect of herring oil on body weight, comb size and gonadal development in the chick.

A diet with 20% herring oil (0.55% linoleate) gave comparable growth responses to a diet containing 20% corn oil (12.07% linoleate) in 4-week-old male and female White Leghorn chicks. No additive or synergistic growth responses were noted in female chicks fed a mixture of herring oil and corn oil. Decreased testes size and changes in testicular histology occurred in young cockerels fed herring oil. Comb responses were dissimilar in male and female chicks fed fish oil.

Animals↗
PubMed2006

Effects of binary mixtures of xenoestrogens on gonadal development and reproduction in zebrafish.

Previous studies exposing fish to xenoestrogens have demonstrated vitellogenin (VTG) induction, delayed gametogenesis, altered sex ratio, and decreased reproductive performance, with a majority of those studies focusing on exposure to single chemicals. The objective of this study was to determine the effects of binary mixtures of a weak estrogen receptor agonist, nonylphenol (NP) and a potent estrogen receptor agonist, 17alpha-ethinylestradiol (EE) on sex ratios, gametogenesis, VTG induction, heat shock protein 70 (HSP70) expression and reproductive capacity in zebrafish (Danio rerio). Fish were exposed from 2 to 60 days post-hatch (dph) to nominal concentrations of 10 or 100 microg/l NP (NP10 or NP100, respectively), 1 or 10 ng/l EE (EE1 or EE10, respectively), 1 ng/l EE+10 or 100 microg/l NP (EE1+NP10 or EE1+NP100, respectively), 10 ng/l EE+10 or 100 microg/l NP (EE10+NP10 or EE10+NP100, respectively) or solvent control (0.01% acetone, v/v) in a static-renewal system with replacement every 48 h. At 60 dph, fish from each treatment were euthanized for histological examination of gonads, and whole body VTG and HSP70 levels. Remaining fish were reared in clean water until adulthood (240 dph) for breeding studies. In all EE10 exposure groups (EE10, EE10+NP10 and EE10+NP100), increasing NP concentration acted antagonistically to the action of EE in terms of VTG induction at 60 dph. Similarly, non-additivity was observed with egg production, where EE1+NP100 exposure resulted in significantly more eggs produced per breeding trial than EE1 alone. Histological staging of oogenesis revealed suppressed gametogenesis in an additive fashion in females at 60 dph. There were no differences among treatment groups in whole body HSP70 expression in 60 dph fish or in gonadal HSP70 expression in adult fish. Although there was no statistical evidence of non-additivity, breeding trials in adults revealed significant reductions in egg viability, egg hatchability and/or F1 swim-up success, suggesting that developmental exposures to xenoestrogens may cause irreversible effects on egg quality and progeny even after periods of depuration. In conclusion, these results suggest that environmentally relevant mixtures of NP and EE can produce additive or non-additive effects that depend on the particular response being determined and the respective exposure concentrations of each chemical.

Animals↗
PubMed1992

Comparative effects of the water accommodated fraction of three oils on mussels. 1. Survival, growth and gonad development.

1. Mussels, Mytilus galloprovincialis, were exposed to the water accommodated fraction (WAF) of two crude oils (types Ural and Maya) and of a commercial lubricant oil for 91 days. Synchronous spectrofluorometry showed that the aromatic hydrocarbon composition of the WAFs obtained from the three oils were significantly different (Maya-WAF heaviest, Ural-WAF lightest). 2. No significant mortality occurred in mussels exposed to the WAFs of the two crude oils, while all the animals exposed to lubricant-WAF died after 49 and 77 days in intermediate and high doses respectively. 3. Flesh and shell growth of mussels exposed to the WAFs was reduced significantly with respect to controls as demonstrated by several size, condition and allometric parameters. The response to petroleum hydrocarbon exposure is not dose-dependent, maximal responses being measured in low (Ural) and intermediate (Maya) doses. This seems to depend on a behavioural reaction (shell valve closure) against high doses of pollutants which may avoid the sublethal damage to some extent. 4. Shell abnormalities or changes in shell thickness were not detected. 5. The histological study of gonad tissue revealed that gamete release is retarded and hemocytic infiltration of mature gonad tissue is increased after exposure to low and intermediate doses of the WAFs. On the other hand, spawning is readily induced under exposure to high doses of the WAFs.

Animals↗
PubMed1988

cDNA cloning and sequence analysis of a chicken gene expressed during the gonadal development and homologous to mammalian cytochrome P-450c17.

A cDNA clone, pLOA0511, was isolated from the cDNA library prepared from the left ovaries of one- to three-day-old chickens. The transcript corresponding to this cDNA clone is approx. 1.9 kb in length and is present in steroidogenic tissues (ovary, testis and adrenal gland) but is undetectable in non-steroidogenic tissues. Relative abundance of the transcript in the ovary and testis is high and developmentally regulated but is much lower in the adrenal gland. Relative levels of this transcript in the developing left ovary and the regressing right ovary of the one- to three-day-old chicken are similar. The nucleotide sequence of this cDNA clone shows significant homology to some mammalian cytochromes P-450. Out of the 508 amino acids (aa) coded, 244 and 243 aa residues are identical with those of the bovine and human cytochrome P-450c17 (steroid 17 alpha-hydroxylase/17,20 lyase), respectively. There are three highly conserved regions among the bovine, human and chicken sequences, one of which is unique to P-450c17. These data suggest strongly that this cDNA corresponds to the mRNA of a chicken cytochrome P-450c17.

Amino Acid Sequence↗
PubMed2006

lin-35/Rb and the CoREST ortholog spr-1 coordinately regulate vulval morphogenesis and gonad development in C. elegans.

Using a genetic screen to identify genes that carry out redundant functions during development with lin-35/Rb, the C. elegans Retinoblastoma family ortholog, we have identified a mutation in spr-1. spr-1 encodes the C. elegans ortholog of human CoREST, a protein containing Myb-like SANT and ELM2 domains, which functions as part of a transcriptional regulatory complex. CoREST recruits mediators of transcriptional repression, including histone deacetylase, and demethylase, and interacts with the tumor suppression protein REST. spr-1/CoREST was previously shown in C. elegans to suppress defects associated with loss of the presenilin sel-12, which functions in the proteolytic processing of LIN-12/Notch. Here we show that lin-35 and spr-1 coordinately regulate several developmental processes in C. elegans including the ingression of vulval cells as well as germline proliferation. We also show that loss of lin-35 and spr-1 hypersensitizes animals to a reduction in LIN-12/Notch activity, leading to the generation of proximal germline tumors. This defect, which is observed in lin-35; spr-1; lin-12(RNAi) and lin-35; spr-1; hop-1(RNAi) triple mutants is likely due to a delay in the entry of germ cells into meiosis.

Animals↗
PubMed1996

Growth hormone, gonad development, and steroid levels in female carp.

The pituitary and plasma growth hormone (GH) levels of female carp (Cyprinus carpio L.) were measured in fish of various sizes and degrees of maturity, and were matched against the levels of 17 beta-estradiol (E2), testosterone (T), 17 alpha-hydroxyprogesterone (17-P), and progesterone (P) in the ovary and plasma. The short-term action of the above hormones and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17,20-P) on the release of GH was examined in vitro in primary culture pituitary cells. The gonadosomatic index (%GSI) increased rapidly in specimens when they had attained 900 +/- 50 g body weight (BW). The pituitary and plasma GH levels increased between 150 and 600 g BW (when oocytes reached the stage at which lipoprotein appeared in the cytoplasm), but at 900 g BW (with oocytes in vitellogenesis) the plasma GH dropped, while pituitary GH remained high. E2 increased with BW, reaching its maximum at 600 and 900 g BW in the ovary and plasma, respectively. Similar patterns were found in the levels of T and P, both hormones reaching their maximum levels at 900 g BW. The level of 17-P was very low and did not increase in proportion to BW. The application of various concentrations of different steroids on a primary culture of pituitary cells led to release of GH. The highest degrees of release were obtained from 10(-6) and 10(-7) M E2, 10(-6) M T, 10(-7) M 17-P and 10(-8) M 17,20-P. In all these cases, hormone treatment effected higher release of GH than was found in the control. A model of the relationship between GH and the steroids associated with maturation is proposed.

Animals↗
PubMed2004

Gonad development and plasma steroid profiles by HRGC/HRMS during one reproductive cycle in reference and leachate-exposed female perch (Perca fluviatilis).

Endocrine processes were studied in reference female perch (Perca fluviatilis) from Lake Djursjön and in leachate-exposed females from Lake Molnbyggen during one reproductive cycle. A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) technique enabled the analysis of circulating sex steroids [progesterone (P), 17alpha-hydroxyprogesterone (17alpha-OHP), androstenedione (A), testosterone (T), estrone (E1), and 17beta-estradiol (E2)], the maturation-inducing hormone (MIH) 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-P), and glucocorticoids [11-deoxycortisol (11-DC) and cortisol]. Body and organ measurements, ratio of sexually mature (SM) females, and frequencies of body lesions, were also recorded. High frequencies of body lesions and a low ratio of SM females were generally found in Molnbyggen. These females also had lower gonadosomatic index (GSI) and liver-somatic index (LSI) in the early stages of vitellogenesis, indicating either a delayed onset of oogenesis or an impaired vitellogenesis. Non-reproducing females from both lakes showed a similar LSI cycle as SM females. Increasing T and A levels in SM females from Djursjön coincided with the GSI peak at the time of spawning. These two androgens were on several occasions lower in SM females from Molnbyggen, possibly the result of a disrupted 17,20-lyase activity of the P450 17alpha enzyme because only minor effects were observed on circulating P and 17alpha-OHP levels. E2 and E1 levels increased during vitellogenesis in females from both lakes, with E1 levels more closely resembling the peaks of A and GSI. Peak levels of 17alpha,20beta-P at the time of spawning confirmed its function as the MIH in perch, while the simultaneous peak of 11-DC suggests that it also may be involved in final maturation of the oocytes.

Animals↗
PubMed1996

Interrelationship of day length and temperature on the control of gonadal development, body mass, and fat score in white-crowned sparrows, Zonotrichia leucophrys gambelii.

We tested the effects of naturally relevant environmental temperatures on long day-induced reproductive development in male and female white-crowned sparrows, Zonotrichia leucophrys gambelii. Transfer from short days (8L 16D) to long days (20L 4D) resulted in rapid testicular development and partial ovarian development as has been reported many times previously. Exposure of experimental groups to low (5 degrees), moderate (20 degrees), and high (30 degrees) temperature during photostimulation had only subtle effects on plasma levels of follicle-stimulating hormone and luteinizing hormone over time and no effects on the size of testes, cloacal protuberance, ovaries, or brood patch at Day 30 of treatment. Long days resulted in the well known increase in body mass and fat score, indicative of preparations for migration. In females, treatment with low temperature resulted in a reduction in the premigratory increase in fat and body mass when transferred to long days. This was accompanied by an increase in plasma levels of corticosterone during the early stages of photostimulation at low temperature. Temperature regimes had no effects on fattening or body mass in males, despite an early increase in plasma corticosterone at low temperature. Circulating levels of thyroxine (T4) and triiodothyronine (T3) increased to varying degrees following photostimulation. Temperature treatment had no effect on plasma levels of thyroid hormones in males, but low temperature did inhibit thyroid hormone secretion (particularly T4) in females. Although reproductive development appears to be resistant to naturally relevant temperature extremes in both sexes, low environmental temperature impaired preparations for migration in females but not males. This effect may be mediated through glucocorticosteroids and not thyroid hormones. Reasons for the sexual dimorphism in this response are unknown, but may be related to sexual selection for males to arrive on the breeding grounds ahead of females regardless of local weather conditions.

Adipose Tissue↗