Tumor Necrosis Factor-a induces apoptosis of lactotropes from female rats

M.CANDOLFI,; V.ZALDIVAR,; A. DE LAURENTIIS,; G.JAITA,; D.PISERA,; A. SEILICOVICH

ENDOCRINOLOGY

ENDOCRINE SOC

Año: 2002 vol. 143 p. 3611 - 3617

0013-7227

Tumor Necrosis Factor-alpha (TNF-á) is involved in the regulation of normal tissue homeostasis affecting cell proliferation, differentiation and death. We previously reported that TNF-á reduces anterior pituitary cell proliferation and prolactin release in an estrogen-dependent manner. In the present project, we studied the induction of apoptosis by TNF-á in anterior pituitary cells from female rats. TNF-á (50 ng/ml) decreased the viability of anterior pituitary cells. Incubation with TNF-á for 24 h increased the percentage of TUNEL positive cells. TNF-a increased the percentage of somatotropes and lactotropes with apoptotic nuclear morphology without affecting the proportion of apoptotic corticotropes or gonadotropes. TNF-á increased the percentage of apoptotic lactotropes in cultured cells from rats killed in proestrus and estrus but not in diestrus. This effect was significantly higher in cells from rats in proestrus than in estrus. In anterior pituitary cells from ovariectomized rats, TNF-á significantly increased the percentage of apoptotic lactotropes only when the cells were incubated in the presence of 17b-estradiol. These results indicate that TNF-á induces apoptosis in somatotropes and lactotropes from female rats. The apoptotic effect of TNF-á on lactotropes is dependent on estrogens and could be involved in the regulation of anterior pituitary cell renewal during the estrous cycle.