The effect of gonadectomy and gonadal hormone replacement on the adrenal cortex activity was studied in the adult male sand rat Psammomys obesus, a diurnal gerbillid rodent living in Beni-Abbes area, in the Algerian Sahara desert (30°7 N, 2°10 W). Animals freshly captured were orchiectomized during the breeding season and some animals received testosterone oenanthate (75 μg per 40 μl olives oil) twice a day during 7 days, 3 weeks after gonadectomy.
In the sand rat Psammomys obesus, orchiectomy increased the adrenal cortex weight (31.5%) and the adrenal content of RNA, DNA, and protein synthesis by respectively 45.1%, 46% and 32.1%. A highly significant increase in cholesterol (50.4%) and total lipids (71.5%) adrenal cortex content was observed after castration. Glucose and total carbohydrate content markedly increased by respectively 65.9% and 62.3%. Plasma cortisol decreased by −81.8% when plasma LH concentrations increased significantly in castrated by 98.9%.
The adrenal cortex apoptosis analysed by in situ end labelling of fragmented apoptotic nuclei DNA (TUNEL) showed that the highest apoptotic index was detected in the most inner zones of the adrenal cortex mainly in the zona reticularis. Nevertheless, androgen deprivation induced an increase in the labelling index in the zona fasciculata, with a decrease in the zona reticularis. The staining intensity in the zona glomerulosa was similar to that observed in non-castrated animals.
Testosterone oenanthate administration to castrated animals restored most of the investigated adrenal cortex content and the zonation of apoptotic cells changed to the status of intact sand rat.
It could be concluded that androgens act as regulatory factors for the programmed cell death and may be involved in the control of the mitotic activity and the turnover of adrenal cortex cells.
03 - 07 May 2008
European Society of Endocrinology