Aim. The aim of the investigation was to make a review of the morphological characteristics of the adrenal cortex following the application of high doses of medroxy­progesterone acetate (MPA).

Material and Methods. Total of 48 female Wistar rats were divided into four groups. Control group was given saline daily, intra­muscularly, and the other three groups MPA in doses of 7.5, 15.0 and 75.0 mg/kg bw during 30 days. Paraffin sections from adrenal glands were stained according the following methods: hematoxylin-eosin, Azan modified by Heidenhein, Van-Gieson, Kossa-Goldner, Masson and Florentin.

Results. Histological analysis demonstrated that MPA caused the following morphological changes in adrenal cortex: more intensive development of stroma; decrease of adrenal cortex thickness; disturbance of spacial organization of adrenocorticocytes in glomerular zone, fascicular zone and reticular zone; atrophic changes of adrenocorticocytes; disappearance of intermediary zone after application of 75.0 mg/kg bw MPA; appearance of microcysts in fascicular and reticular zones; decrease of cortical proliferate dimensions and accessory adrenal glands, disappearance of spongiocytes from their structure and atrophic changes of glomerular cells; decrease of adrenal cortex vascularisation, necrotic changes localized subglomerularly and in fascicular zone of adrenal cortex.

Conclusion. MPA causes atrophic changes in adrenal cortex i.e., the decrease of its cell potential, a phenomenon suggesting that MPA possesses glucocorticoid characteristic.