[Morpho-functional endocrine glands changes in male and female rats under deficiency of functional loading]

Histomorphometric and immunocytochemical methods were employed in comparative morphofunctional analysis of the endocrine glands of female and male rats deprived of support loads on the hind limbs by tail suspension. It was shown that pituitary somatotrophs, pancreatic insulocytes and thyroid calcitonin-producing cells in females and males react to deficiency of support loading equally by reducing the functional activity. Blood testosterone decreases in the tail-suspended rats and concurrent hyperplasia of Leydig's cells in testicles are suggestive of an abnormal testosterone synthesis/secretion by these cells in consequence of resticle displacement toward the abdomen. Activation of adenohypophysial gonadotrophs producing the luteinizing hormone that controls the Leydig's cells proliferation appears to be a feedback reaction of gonadotrophs to the low testosterone level in blood.