Volume 55 (2005) Issue: 2005 No#2-3

Estradiol and calcium affect the growth hormone-producing cells in female middleaged rats

Author(s): Milošević Verica, Trifunović Svetlana, Šošić-Jurjević Branka, Bujšić Nada, Sekulić Milka

Keywords:estradiol, GH cells, growth hormone, middle aged, rat females

The effects of multiple doses of estradiol dipropionate (EDP) or calcium glucoheptonate (Ca) on the growth and function of pituitary somatotropes (GH cells) were studied. Female middle-aged rats were receiving i.p. EDP (0.625 mg i.p./kg b.w.), or Ca (11.4 mg/kg b.w) every day for two weeks. Blood samples were collected for hormone analyses and pituitaries dissected for histological and morphometric evaluation 24 h after the last injection. GH-producing cells were examined using the peroxidase-antiperoxidase (PAP) immunohistochemical procedure. Both EDP- and Ca-treatment significantly decreased all morphometric parameters of GH cells (p<0.05) in comparison with the corresponding controls. Serum concentration of growth hormone (GH) in EDP- or Ca-treated groups was lower by 65% and 13% (p<0.05) respectively, comparing to the controls. The difference between all morphometric parameters of EDP- and Catreated rats was statistically significant (p<0.05) in relation to the controls. These findings suggest that multiple EDP, or Ca application affects (directly or indirectly) the control of growth and secretory activity of GH cells in middle-aged female rats.