The role of insulin and renin in the pathogenesis of hormone-dependent neoplasias. a). Insulin.

Weight increase is frequently observed in women of menopausal age and the androgens secreted at the ovarian level are converted into estrogens at adipose tissue level, because of the presence of specific enzymes, the aromatases. Insulin and the androgens reduce the synthesis of Sex Hormone Binding Globulin (SHBG) at the hepatic level, thus increasing the amount of free steroids able to act at the level of the hormone-dependent tissues. Besides, the insulin stimulates androgenic synthesis at the level of the ovarian stroma in postmenopausal women. In this research, we studied 83 postmenopausal women, 41 with hormone-dependent pathologies and 42 affected by other pathologies, and we observed that women affected by breast and endometrial neoplasias presented a reduced tolerance to glucose, a higher level of circulating androgens, a large quantity of fatty tissue and a SHBG concentration inversely proportional to insulin level. These results suggest that the ovarian synthesis of androgens increase in women in postmenopausal age affected by hormone-dependent pathologies, and that insulin may play a part in the pathogenesis of such neoplasias.