Effects of intracerebroventricularly administered octreotide on gonadotrophic cells in female rats

Effects of intracerbroventricularly (ICV) administered octreotide on gonadotrophic cells (FSH and LH) of adult Wistar female rats were examined by immunocytochemical and morphometric methods. The animals received ICV three 1.0 mg doses of octreotide dissolved in 10 mL saline every second day. The controls were treated with equivalent volume of physiological saline by the same schedule. FSH- and LH-producing cells were examined using peroxidase-antiperoxidase immunocytochemical procedure. Morphometric and stereologic examinations were performed to evaluate changes in the number, volume and volume densities of gonadotrophic cells. In females treated with octreotide, the gonadotrophic cells were smaller and often pycnotic, while the number of FSH- and LH-immunopositive cells per unit area (mm2) was significantly reduced. Octreotide also induced a significant reduction of the FSH- and LH-immunoreactive cells volume, as well as of their volume densities. On the basis of these results it can be concluded that octeotride, centrally administered to adult female rats provokes changes in immunocytochemical and morphometric features of both types of gonadotrophic cells.

Dexamethasone induces an increased biosynthesis of chromogranin A in rat pituitary gland

ABSTRACT The influence of dexamethasone on the regulation of the biosynthesis of chromogranins A and B, two proteins originally described in adrenal chromaffin granules, was investigated in the rat pituitary gland. Dexamethasone increased chromogranin A levels and its corresponding mRNA in a dose-dependent manner. Induction of chromogranin A occurred with a time-lag of 24 h. As shown by immunohistochemistry, chromogranin A was present in control and dexamethasone-treated rats in gonadotrophic cells only. Chromogranin B, secretogranin II and the respective pituitary hormones co-stored with chromogranin A were not changed by dexamethasone. Thus dexamethasone selectively increased chromogranin A levels in gonadotrophic cells. Journal of Endocrinology (1989) 121, 487–494