Morphofunctional characteristics of adrenal cortex in female rats after centrally applied somatostatins

Abstract

The effects of intracerebraventricular (i.c.v.) administration of somatostatins (SRIH-28 or SRIH-14) on zona glomerulosa (ZG) and zona fasciculata (ZF) of the adrenal cortex and blood concentration of adrenocorticotropic hormone (ACTH), aldosterone, cortisol, Na+ and Kf ions in female rats were studied. Each experimental animal was given three 1.0 mug doses of SRIH-28 or SRIH-14 dissolved in 5.0 muL saline by i.c.v. route every second day. Controls were treated in the same way with an equal volume of saline. The rats were sacrificed by decapitation 5 days after the last SRIH injection. The left adrenal gland of each animal was dissected out and prepared for morphometric analyses. Blood samples were collected for hormone level determinations. SRIH-28 but not SRIH-14, led to a significant reduction of absolute and relative volume of the ZG in comparison with the controls (p < 0.05). Total number and volume of the ZG cells and their nuclei was also significantly reduced in SRIH-28-treated rats (p < 0.05) as compared to the controls. No significant changes in morphometric parameters of ZF were recorded. At the same time, a significant decrease of aldosterone, ACTH and Na+ levels were observed (p < 0.05) only in animals treated with SRIH-28, while cortisol concentration was almost unaltered and that of K+ ion significantly increased in comparison with control values. These results indicate that centrally applied SRIH-28 but not SRIH-14, acts inhibiting both the secretory activity and growth of adrenal ZG cells, while insignificantly affecting ZF cells.