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Plasma steroid concentrations in relation to the reproductive cycle of cultured male Rhamdia quelen
Author(s) -
Barcellos L. J. G.,
Wassermann G. F.,
Scott A. P.,
Woehl V. M.,
Quevedo R. M.,
Ittzés I.,
Krieger M. H.,
Lulhier F.
Publication year - 2002
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2002.tb00909.x
Subject(s) - biology , milt , medicine , endocrinology , spermatogenesis , steroid , testosterone (patch) , reproduction , sex steroid , sperm , androgen , steroid hormone , fish <actinopterygii> , hormone , fishery , ecology , botany
The plasma concentrations of testosterone (T) of cultured jundiá Rhamdia quelen increased progressively during spermatogenesis and reached a peak at the beginning of spermiation (e.g. fluidization of the sperm and production of milt). Plasma peaks of T occurred simultaneously to the highest production of T by the testis, however, both plasma concentrations and testis production of T decreased progressively during spermiation. Concentrations of 11‐ketotestosterone (11‐KT) peaked c . 1 month after the peak of T, concomitant with enhanced production of 11‐KT by the testis. The concentrations of 11‐KT during the first cycle were extremely high (> 1 μg ml −1 ), but less during the second and third cycles, suggesting that this steroid is most important during the pubertal phase in male jundiá. Plasma concentrations of both 17‐hydroxy‐4‐pregene‐3,20‐dione (17‐P) and 17,20 β ‐dihydroxy‐4‐pregen‐3‐one (17,20 β ‐P) were significantly higher during spermiation than at any other times, and showed little variation. The pattern of steroid changes was cyclical and consistent with their proposed roles in male fish reproduction.