angiotensin-iii and Testicular-Neoplasms

Renin and angiotensins coexist in various tissues. The mode of control of the extrarenal renin-angiotensin system is not clear. Whether it is renin or angiotensin that is secreted has not been identified. We have investigated gonadotropin-dependent synthesis and subsequent release of the components of the intracellular renin-angiotensin system in a cloned and cultured mouse Leydig tumor cell line (MA-10). Treatment of cultured Leydig cells with bovine luteinizing hormone (bLH, 100 ng/ml) or human chorionic gonadotropin (hCG, 25 ng/ml) resulted in greater than 150- and 40- fold increased formation of angiotensin I and angiotensin II. In cells incubated with bLH or hCG, the majority of AII (up to 90%) was found in the culture medium while most of angiotensin I (greater than 85%) was in the cell lysate. Treatment with gonadotropic hormones (bLH/ hCG) increased renin 35- to 40-fold. Renin activity was confined mainly in the cell lysate even after the stimulation by gonadotropins, and only 1-2% of the total renin activity was detectable in culture medium. These results were interpreted that, in these transformed cells, hormonally-induced renin functions to generate angiotensin I within the Leydig cell and it is the angiotensins which are secreted.

Topics: Angiotensin I; Angiotensin II; Angiotensin III; Animals; Cells, Cultured; Chorionic Gonadotropin; Chromatography, High Pressure Liquid; Leydig Cell Tumor; Luteinizing Hormone; Male; Mice; Mice, Inbred C57BL; Radioimmunoassay; Renin; Testicular Neoplasms; Time Factors