G. Biagini et al., CHANGES IN GLUCOCORTICOID RECEPTOR IMMUNOREACTIVITY AFTER ADRENALECTOMY AND CORTICOSTERONE TREATMENT IN THE RAT TESTIS, Journal of endocrinological investigation, 18(5), 1995, pp. 384-390
The distribution of glucocorticoid receptor (GR) in the rat testis was
investigated by means of immunocytochemistry (IR) and computer-assist
ed image analysis. A monoclonal antibody against rat liver GR showed t
he presence of GR IR selectively in the nuclei of interstitial and tub
ular cells. The semiquantitative microdensitometry of GR IR revealed t
hat 77% of the specific staining was localized in the tubular compartm
ent of rat testis. After adrenalectomy, GR IR was greatly reduced both
in interstitial and tubular cells, roughly at the same degree. Cortic
osterone treatment (50 mg/kg, for 5 d) of adrenalectomized animals yie
lded a recovery of nuclear immunopositivity without changing the cellu
lar distribution of GR, as observed in control rats. Nevertheless, the
high dose of corticosterone administered produced a significant (p<0.
01) decrease of GR IR with respect to control rats. These results prov
ide evidence for a prevalent nuclear binding of GR in the tubular comp
artment in basal conditions. On the other hand, adrenalectomy or repea
ted corticosterone treatment seem to affect GR similarly in all positi
ve cells without changing significantly the proportion of GR IR in the
different testicular compartments. This uneven distribution of GR IR
suggests that tubular cells can be a major target of corticosterone wh
en affecting directly testicular functions in the rat.