Renin expression in rat testis is controlled by gonadotropin

Abstract

The effect of human chorionic gonadotropin (HCG) on renin concentration and renin mRNA was studied using the testis and kidney of rats. Forty-five rats were divided into three groups. The first group (25 rats) was used for short time course study with single injection of 150 IU HCG and the second group (10 rats) for long term injection of 150 IU HCG daily for 3 weeks. In both groups, serum and testicular sample were taken after 24 hours both nephrectomy in order to exclude the influence of renal renin and angiotensin. The third group (10 rats) was used to find the effect of HCG on renal renin. Plasma and testicular renin concentration were measured by radioimmunoassay of angiotensin I. The specificity of renin concentration was determined using a specific renin antibody. Renin mRNA of the kidney and testis were measured by a sensitive RNAase protection assay method. Testicular renin mRNA increased and reached the maximum level at 8 hrs after 150 IU HCG single injection. And also testicular renin concentration significantly increased and it showed the maximum levels at day 3. However long term HCG administration in rats showed higher in levels in testicular renin concentration, however renin mRNA level was not increased. Non-nephrectomized rats showed low levels of plasma renin concentration and no changes in mRNA after HCG administration. The results suggest that renin angiotensin results suggest that renin angiotensin system independently exists in the testis and testicular renin mRNA is increased by HCG administration.