Pituitary thyrotropic cells are affected by steroid hormones

Abstract

The pituitary gland is a heterogeneous tissue comprised of several hormone-secreting cells most of which are targeted by sex steroids. Our long-term studies were concentrated on the response of rat pituitary TSH cells to gonadal steroids applied to animals of different age. With this goal, we examined immunoreactive and morphometric, as well as subcellular organization of pituitary TSH cells in rats of both sexes after neonatal and perinatal estradiol-dipropionate (EDP) treatment. The results undoubtedly indicated persistent EDP-related inhibitory changes of tyrotrophs up to the adulthood. At the subcellular level, a delayed differentiation of TSH cells was noticed. Besides, a special attention has been paid to the changes in the structure of immunoreactive TSH cells of middle-aged (14-month-old) rat females, chronically treated with EDP, calcium (Ca) or a combination of EDP and Ca. Based on our results it can be concluded that both EDP and Ca act inhibiting the thyrotrophs under the applied experimental conditions.