Effects of estradiol and calcium on gonadotrophic cells in middle-aged female rats

The effects of multiple treatment with estradiol dipropionate (EDP) or calc ium glucoheptonate (Ca) or a combination of the two on gonadotrophic cells in the pituitary pars distalis of middle-aged female rats were examined. Th e animals were treated daily for two weeks with EDP (0.625 mg i.p./kg body weight) or Ca (11.4 mg/kg body weight) or EDP+Ca. Luteinising (LH) and foll icle stimulating hormone (FSH)-producing cells were examined by immunohisto chemistry using antisera to the specific (beta) beta-subunits of LH and FSH and a peroxidase-anti-peroxidase immunohistochemical procedure. Plasma lev els of FSH and LH were measured by radio-immune assay. A stereological meth od for determining morphometric parameters in immunopositive FSH and LH cel ls was used. The number of gonadotrophs per unit area (mm(2)), their cellul ar volume and relative volume densities, as well as plasma levels of FSH an d LH, were decreased in all treated females in comparison with the controls . The most significant decrease of these parameters was observed in EDP-tre ated animals. Such changes were also expressed in Ca-treated animals, but t he alterations were less distinct. These results demonstrate that multiple EDP or Ca application to middle-aged female rats is able to inhibit, direct ly or indirectly, the morphofunctional state of gonadotrophic cells in the pituitary pars distalis.