Salmonid Follicle-Stimulating Hormone (GtH I) Mediates Vitellogenic Development of Oocytes in the Rainbow Trout, Oncorhynchus mykiss

Tyler, C.R.; Pottinger, T.G.; Coward, K.; Prat, F.; Beresford, N.; Maddix, S.. 1997 Salmonid Follicle-Stimulating Hormone (GtH I) Mediates Vitellogenic Development of Oocytes in the Rainbow Trout, Oncorhynchus mykiss. Biology of Reproduction, 57 (5). 1238-1244. 10.1095/​biolreprod57.5.1238

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Abstract/Summary

Rainbow trout (Oncorhynchus mykiss) were subjected to unilateral ovariectomy (ULO) during early vitellogenesis to examine the endocrine responses mediating the recruitment and growth of oocytes in the secondary (vitellogenic) growth phase. ULO induced recruitment of a second population of primary oocytes into the vitellogenic growth phase that then grew at a faster rate than oocytes in the control fish. Seven days post-ULO, the concentration of plasma salmonid FSH (sFSH = GtH I) was significantly higher than in controls and was elevated for at least 54 days. Maximal concentrations of sFSH in ULO fish (Day 21 post-ULO) were twice (10 ng/ml) those in controls. The data show that sFSH plays a primary role in mediating vitellogenic development. After ULO, plasma concentrations of estradiol-171 were significantly lower than in controls up until 21 days post-ULO. Thereafter, plasma concentrations of estradiol-17 1 did not differ from those in controls. The changes in concentrations of plasma estradiol-170 and sFSH in the ULO fish demonstrated that the secretion of sFSH is probably not controlled by negative feedback of estradiol-17 alone; in fish, as in mammals, it is likely that intragonadal autocrine/paracrine factors, such as inhibin and activin, also participate in the regulation of sFSH secretion. Plasma concentrations of testosterone did not appear to differ between the control and ULO fish. The responses in the production of estradiol-17j3 and testosterone indicate that the dynamics of sex steroid synthesis in ovarian follicles in ULO fish was different than in the ovaries of control fish.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1095/​biolreprod57.5.1238
UKCEH and CEH Sections/Science Areas:	_ Pre-2000 sections
ISSN:	0006-3363
Additional Information. Not used in RCUK Gateway to Research.:	Click on the official URL to access freely available full text
Additional Keywords:	rainbow trout, Oncorhynchus mykiss, ovulation, FSH, vitellogenesis, ovariectomy, estradiol, testosterone
NORA Subject Terms:	Zoology Biology and Microbiology
Date made live:	28 Jul 2015 09:28 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/510953

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