Somatostatin 14 affects the pituitary-ovarian axis in infant rats

Abstract

The effects of multiple somatostatin (SRIH-14) treatment on the pituitary-ovarian axis were examined in infant rats. Female Wistar rats received subcutaneously two daily 20 mu g/100g b.w. doses for five consecutive days (from 11 to 15 days of age). Changes in cell volume, volume density and number per unit area (mm(2)) of follicle-stimulating (FSH), luteinizing (LH) and somatotropic (GH) immunolabeled cells were evaluated by stereology and morphometry. Serum FSH and LH concentrations were determined by RIA. Ovaries were analyzed by simple point counting of follicles. SRIH-14 treatment significantly reduced FSH and LH cell volume, while their volume density and number per unit area were unaltered. Serum concentrations of FSH and LH were significantly reduced. Volume and volume density of GH cells was significantly decresed after SRIH-14 treatment, while their number per unit area was unaltered. In the ovary, SRIH-14 induced a significant increase in the percentage of primordial follicles followed by a significant decrease in percentage of primary follicles. The number of healthy and atretic preantral follicles was unchanged. It can be concluded that SRIH-14 treatment during the infantile period markedly inhibits pituitary FSH, LH and GH cells. In the ovary, SRIH-14 acts by inhibiting initial folliculogenesis without affecting atretic processes.