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6970370 
Journal Article 
CHANGES IN THE PLASMA STEROID-HORMONE LEVELS DURING GONADAL MATURATION IN THE FEMALE CATFISH CLARIAS-BATRACHUS 
Singh, A; Singh, TP; , 
1991 
0 
Zoologische Jahrbücher
ISSN: 0044-5185 
GUSTAV FISCHER VERLAG JENA 
JENA 
209-220 
WOS:A1991FJ59600007 
Levels of estradiol-17-beta (E2), testosterone (T), 17-alpha-hydroxyprogesterone (17-alpha-DHP) and 17-alpha-20-beta-dihydroxy progesterone (17-alpha-20-beta-DHP) were assayed by radioimmunoassay in female catfish, Clarias batrachus concomitantly with advancing maturation of the gonads during prespawning and spawning season of their annual reproductive cycle. Concentrations of E2 and E1 were higher in females with eggs showing Central Germinal Vesicle (GV). Germinal Vesicle Offcentre (GVOC) and migratory GV (GVM) than those in which the eggs had undergone Germinal Vesicle Breakdown (GVBD) or ovulation. Conversely, plasma levels of 17-alpha-20-beta-DHP were low at central, off centre and migratory GV and then increased considerably at GVBD. The testosterone levels showed a rapid increase at GV migratory position and there after declined sharply at the next stage (GVP). 17-alpha-hydroxy progesterone levels increased in the females at the time of final maturation (GV peripheral) and a decline was observed at germinal vesicle breakdown. A change in ovarian steroidogenesis in Clarias batrachus leading to the production of maturation inducing steroid, coincident with the initiation of final oocyte maturation, is clearly demonstrated in the present study.