The aim of the present study was to examine the morphometric characteristics
of folliclestimulating hormone (FSH) and luteinizing hormone (LH)
immunoreactive cells in the pituitaries of orchidectomized (Orx) and Orx
testosterone- or estradiol-treated rats. Adult male Orx Wistar rats, 2 weeks
post operation, received estradiol dipropionate (E) or testosterone
propionate (T) for 3 weeks. Both controls, sham-operated (So) and Orx rats,
were injected with solvent, in the same regime. Changes in the volume of pars
distalis, the volumes of individual FSH- and LH-labeled cells, their
numerical density and number were determined by unbiased design-based
stereology. The FSH and LH intracellular content was estimated by relative
intensity of fluorescence (RIF). We observed that Orx caused hyperstimulation
of gonadotropic cells. Their volume, volume density, number, numerical
density and intracellular hormone content significantly increased in
comparison to So controls. Compared to Orx controls, T caused a significant
decrease in the volume and volume density of gonadotropic cells and
immunoreactive FSH and LH formations in their cytoplasm. The volume of the
pars distalis, the numerical density and number of gonadotropic cells were
not changed as compared to Orx controls. Estradiol treatment caused a
significant increase in the volume of the pars distalis, decreases in cell
volume, volume and numerical density of gonadotropic cells, and FSH and LH
intracellular content in comparison to Orx controls. The number of
FSH-labeled cells increased. In conclusion, both T and E reversed all of the
examined parameters of gonadotropic cells of Orx rats to the level of So
controls, except in number.