Specific changes of pituitary cells after centrally applied somatostatins to rats of both sexes

Abstract

The effects of intracerebroventricularly (i.c.v.) administered somatostatins (SRIH-14 or SRIH-28) on growth and function of pituitary somatotropes (CH cells), mammotropes (PRL cells), corticotropes (ACTH cells), thyrotropes (TSH cells), and gonadotropes (FSH- and LH cells), were examined in adult Wistar rats of both sexes. All producing cells were studied using the peroxidase-antiperoxidase immunohistochemical procedure. Blood samples were collected for hormone (CH, PRL, ACTH, TSH, FSH and LH) level determination 5 days after the last somatostatin injection. Both SRIH treatmens led to a significant decrease of all morphometric parameters (volume of the cells and their nuclei, as well as volume density) of GH-, PRL-, TSH- LH-cells in male and female rats in comparison with the corresponding controls. These parameters of ACTH cells were significantly changed in female rats treated with SRIH-28, but not with SRIH-14, as compared to control females. Gonadotrophic FSH cells in male and female rats were not significantly altered in either of somatostatintreated groups comparing to the controls. Changes in blood concentration of hormones secreted by the corresponding specific secretory cells were similar to those of the morphometric parameters of these cells. These observations suggest that centrally administered SRIH-14 or SRIH-28 are specifically involved in the control of growth and secretory activity of GH-, PRL-, TSH- and LH-pituitary cells.