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.