Somatostatin-14 and -28 in the male rat reproductive system

Somatostatin-14 (SRIF-14) has been shown to occur throughout the male rat reproductive system by SRIF radioimmunoassay, Sephadex G-50 exclusion chromatography, and parallel line analysis. SRIF-28 was found only in the epididymis. The highest concentrations of total SRIF-like immunoreactivity (SLI), representing the combined concentrations of SRIF-14 and SRIF-28, were measured in the prostates of 1 1/2- and 3-month-old Sprague-Dawley rats. The levels of SLI in prostates from 9-month-old males were about 10% that of the younger animals. Dilution curves for extracts of all reproductive tissues were parallel with synthetic SRIF-14.