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Not AvailableThe inhibins are disulphide-linked heterodimeric glycoproteins that belong to the TGFb superfamily. Inhibins have been well studied in mammals but the information about their structure and function is very limited in lower vertebrates. The aim of the present study was to characterize inhibin-A and to understand its receptor binding interaction, and to evaluate its biological function in Clarias batrachus. Structure prediction of inhibin-A revealed two glycosylation sites on inhibin-a (Asp262 and Asn334). Docking of inhibin-A with its receptor; betaglycan and Act RIIA showed that residues Ser321, Gly324 and Leu325 of inhibin-a are involved in high affinity binding with betaglycan while inhibin-bA bound to Act RIIA by forming hydrogen bonds. The mRNA transcript analysis of various tissues indicated the presence of higher to moderate expression of inhibin-a and inhibin-bA in the gonads and the extra- gonadal tissues. Further, stage specific expression showed decreased levels of inhibin-a in the gonads during the annual reproductive cycles. Inhibin-bA, activin-bB and Act RIIA increased in the brain during spawning while FSHr increased in the gonads during the preparatory phase. Our study provides molec- ular, structural and functional insights of inhibin-A for the first time in C. batrachus.Not Availabl

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Not Availablenhibins are members of the transforming growth factor beta (TGFβ) superfamily known to regulate ovarian functions through stimulation of the hypothalamo-pituitary-gonadal axis. In the present study, we aimed to de- sign a species-specific inhibin-α chimeric peptide (ICP) and evaluate the effect of immunoneutralization using anti-ICP antisera to enhance the reproductive performance in female Clarias batrachus. Injection of anti-ICP antisera caused a significant increase in the number of oocytes at a medium dose (200 μl) in comparison to high dose (400 μl) and control (normal rabbit serum). Histological observations confirmed the dose- dependent advancement in oocyte maturation. Furthermore, anti-ICP antisera treated groups exhibited a signif- icant increase in the serum concentrations of follicle stimulating hormone (FSH) and 17β-estradiol (E2) hor- mones. The anti-ICP antisera decreased the mRNA expression levels of inhibin-α while stimulated the transcript levels of inhibin-βA, FSHβ, CYP 19a1, 3β-HSD and StAR respectively in a dose-dependent manner. Col- lectively, these findings indicate that anti-ICP antibody macromolecules modulate the endogenous reproductive hormonal secretion and enhance oocyte quality and quantity in female C. batrachus. This is the first report wherein antibodies against inhibins were used to promote reproductive performances and investigate the under- lying molecular mechanisms in fishes.Not Availabl