Impaired testicular cytochrome P450 side-chain-cleavage (P450scc) and steroidogenic acute regulatory (StAR) protein expression in rats with nephrotic syndrome.

Alterations at the pituitary-testicular axis has been already characterized in nephrotic syndrome. Particularly low concentrations of progesterone, testosterone and undetectable levels of estradiol have been associated to the nephrotic condition. Accordingly, to determine if the hormonal withdrawal is the result of steroidogenic failure, we evaluated the expression of testicular cytochrome P450 side-chain-cleavage (P450scc) and steroidogenic acute regulatory (StAR) protein in PAN-induced nephrotic rats. The mRNAs were evaluated on day 10 before and after hCG administration to control and nephrotic rats. The concentrations of progesterone, testosterone, estradiol, and corticosterone were measured by radioimmunoassay. The testicular and adrenal expression of P450scc and StAR were evaluated by Northern hybridization. On day 10, gonadal steroids decreased in nephrotic rats, while after hCG administration the hormonal responses from nephrotic groups were similar to the controls, except estradiol which remained undetectable. Interestingly, in nephrotic testis P450scc and StAR mRNAs were not detected neither on day 10 nor after hCG stimulation, except by the increased expression of StAR after one dose of hCG. In conclusion, this study demonstrates that the expression of P450scc and StAR protein are highly impaired during nephrotic syndrome.