Andropause, the culminating phase of ageing in males is characterized by the
decline of the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis
that is responsible for somatic development. Estrogens on the other hand,
assume a relevant somatic role, as well as the one in the pituitary. They are
particularly interesting because of their therapeutic uses in certain common
ageing-associated diseases. The aim of the present study was to examine the
effects of subcutaneous treatment with estradiol, dipropionate on the
immunohistomorphometric features of GH cells, in an animal model of the
andropause. Sixteen-month-old Wistar rats were divided into sham-operated
(SO), orchidectomized (Orx) and estradiol dipropionate-treated
orchidectomized (Orx+Edp) groups. Estradiol dipropionate (0.625 mg/kg/day)
was administered subcutaneously for three weeks while the SO and Orx groups
received the vehicle alone. GH cells were identified by the
peroxidase-antiperoxidase (PAP) immunohistochemical procedure. In the Orx+Edp
group, GH cell volumes as well as the relative volume densities were
significantly (p<0.05) decreased, by 27.4% and by 61.1%, respectively, in
comparison with the same parameters of SO animals. Compared to the Orx
animals, the cell volumes and relative volume densities of GH cells in
Orx+Edp group were also significantly (p<0.05) decreased, by 23.2% and by
64.1%, respectively. It can be concluded that chronic estradiol dipropionate
application in an animal in the andropause results in the suppression of
immunohistochemical and morphometric parameters of pituitary GH cells.