In vitro effects of lead nitrate on steroid profiles in the post-vitellogenic ovary of the catfish Heteropneustes fossilis

Heavy metals are endocrine disruptors with the ability to cause hormonal imbalances, affecting various physiological processes such as reproduction. In this study, in vitro effects of exposure (12 or 24 h) of lead nitrate [Pb(NO3)2] (0, 0.01, 0.1, 1, 3 and 10 μg/ml) on steroid levels in post-vitellogenic catfish (Heteropneustes fossilis) ovary was investigated. Steroids were assayed by HPLC/ELISA. Lead (Pb) elicited biphasic effects on estradiol-17β, testosterone and cortisol: stimulatory at lower concentrations and inhibitory at higher concentrations. In contrast, progesterone, 17-hydroxyprogesterone, 17,20β-dihydroxyprogesterone, corticosterone, 21-deoxycortisol and deoxycorticosterone were inhibited in a dose-dependent manner. Thus, the present results suggest that short-term Pb response can be a potent endocrine disruptor of normal follicular steroidogenesis. The stimulatory effect on E2 suggests that Pb in trace amounts may be beneficial. The cortisol elevation may be indicative of the metal/stress insult. Nevertheless, further studies are required to understand the mechanism of action of lead toxicity.