Gonadotropins, their receptors, and the regulation of testicular functions in fish

Schulz, Rüdiger; Vischer, HF; Cavaco, José E.; Santos, Eduarda M.; Tyler, Charles R.; Goos, H.J.Th.; Bogerd, Jan

doi:10.1016/s1096-4959(01)00339-6

Cited by 131 publications

(62 citation statements)

References 61 publications

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“…However, after spawning 11-KT levels did not differ between animals that brooded versus those that did not brood. This suggests that spawning rather than brooding is the causal factor explaining the decrease in 11-KT levels (see Oliveira et al, 2001a;Oliveira et al, 2001c) and is consistent with observations in other teleosts in which 11-KT is highest during testicular growth (Schulz et al, 2001;Weltzien et al, 2002). High 11-KT levels have been found to be inhibitory for the final stages of testis maturation (Ikuta et al, 1987).…”

Section: Discussionsupporting

confidence: 85%

Endocrine correlates of intra-specific variation in the mating system of the St. Peter's fish (Sarotherodon galilaeus)

Ros

Canário

Couto

et al. 2003

Hormones and Behavior

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The Challenge Hypothesis postulates that androgen levels are a function of the social environment in which the individual is living. Thus, it is predicted that in polygynous males that engage in social interactions, androgen levels should be higher than in monogamous animals that engage in parental care. In this study, we tested this hypothesis at the intra-specific level using a teleost species, Sarotherodon galilaeus, which exhibits a wide variation in its mating system. Experimental groups of individually marked fish were formed in large ponds with different operational sex-ratios (OSR) to study the effects of partner availability on blood plasma levels of sex steroids [11-ketotestosterone (11-KT), testosterone (T), and 17,20␤-dihydroxy-4-pregnen-3-one (17,20␤-P)] and gonadosomatic index (GSI). Polygyny mostly occurred in the female biased OSR groups. 17,20␤-P and gonadosomatic index did not differ among OSR groups. However, 11-KT was high in male biased OSR and positively correlated with aggressive challenges, thereby supporting the central postulate of the Challenge Hypothesis. The results of T were the inverse of those of 11-KT, probably because 11-KT is metabolized from T. 11-KT levels of polygynous males did not differ neither from those of monogamous males, nor from those of males that participated in parental care. These results do not support the expected relationships between polygyny, parental care, and androgen levels. The differences from expectations for 11-KT may be related to the fact that in S. galilaeus, the mating and the parenting phase are not clearly separated and thus, males may still fight and court while they are brooding.

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Section: Discussionsupporting

confidence: 85%

Endocrine correlates of intra-specific variation in the mating system of the St. Peter's fish (Sarotherodon galilaeus)

Ros

Canário

Couto

et al. 2003

Hormones and Behavior

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“…Dopamine agonists have also been associated with Leydig cell hyperplasia and neoplasia in rats (Dirami et al, 1996;Cook et al, 1999). Luteinizing hormones are believed to play a role in the regulation and production of male reproductive hormones (Schulz et al, 2001). Exposure to the pharmaceutical ketoconazole, used as an experimental prototype for the imidazole and triazole fungicides, resulted in reduced egg production and Leydig cell proliferation in fathead minnows.…”

Section: Discussionmentioning

confidence: 99%

Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay

Blazer

Pinkney

Jenkins

et al. 2013

Science of The Total Environment

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Iwanowicz, Luke R.; Minkkinen, Steven; Draugelis-Dale, Rassa O.; and Uphoff, James H., "Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay" (2013 H I G H L I G H T S► Reduced recruitment of yellow perch has occurred in urban tributaries of Chesapeake Bay. ► We compared reproductive health biomarkers in perch from two urban, one developing, two less developed watersheds. ► Lack of final maturation, abnormal yolk and zona pellucida were noted in females. ► Leydig cell proliferation was noted in males. Reduced recruitment of yellow perch has been noted for a number of years in certain urbanized watersheds (South and Severn Rivers) of the Chesapeake Bay. Other rapidly developing watersheds such as Mattawoman Creek are more recently showing evidence of reduced recruitment of anadromous fishes. In this study, we used a battery of biomarkers to better document the reproductive health of adult yellow perch collected during spring spawning in [2007][2008][2009]. Perch were collected in the South and Severn Rivers, Mattawoman Creek and the less developed Choptank and Allen's Fresh watersheds for comparison. Gonadosomatic indices, plasma reproductive hormone concentrations, plasma vitellogenin concentrations and gonad histology were evaluated in mature perch of both sexes. In addition, sperm quantity (cell counts) and quality (total and progressive motility, spermatogenic stage and DNA integrity), were measured in male perch. Many of these biomarkers varied annually and spatially, with some interesting statistical results and trends. Male perch from the Choptank and Allen's Fresh had generally higher sperm counts. In 2008 counts were significantly lower in the perch from the Severn when compared to other sites. The major microscopic gonadal abnormality in males was the proliferation of putative Leydig cells, observed in testes from Severn and less commonly, Mattawoman Creek perch. Observations that could significantly impact egg viability were an apparent lack of final maturation, abnormal yolk and thin, irregular zona pellucida. These were observed primarily in ovaries from Severn, South and less commonly Mattawoman Creek perch. The potential association of these observations with urbanization, impervious surface and chemical contaminants is discussed. a b s t r a c t a r t i c l e i n f oPublished by Elsevier B.V.

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“…It is well established that gonadotropins play a major role in the endocrine regulation of spermatogenesis in vertebrates (Schulz et al, 2001). However, it is not clear whether hCG acts on spermatogonia cell proliferation either through mediation of KT production by Leydig cells as evidenced for the Japanese eel (Nagahama, 1994) or by acting on some other testicular cell types such as Sertoli cells (Loir, 1999).…”

Section: Discussionmentioning

confidence: 99%

Spermatogenesis in testis primary cell cultures of the tilapia (Oreochromis niloticus)

Tokalov

Gutzeit

2005

Developmental Dynamics

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Gonadotropins, their receptors, and the regulation of testicular functions in fish

Cited by 131 publications

References 61 publications

Endocrine correlates of intra-specific variation in the mating system of the St. Peter's fish (Sarotherodon galilaeus)

Endocrine correlates of intra-specific variation in the mating system of the St. Peter's fish (Sarotherodon galilaeus)

Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay

Spermatogenesis in testis primary cell cultures of the tilapia (Oreochromis niloticus)

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