Endocrine Abstracts

Orchidectomy performed during breeding season (winter) in the adult male gerbil, Gerbillus tarabuli, live trapped in its natural biotope in Béni Abbès area (30°7 N., 2°10 W.) in algerian Sahara desert, induced 50 days later, important weight, histological and hormonal changes on the adrenal gland.

Adrenal weight increases by 69.7% (P=0.06) and adrenal cortex height by 48.6% (P=0.00) with hypertrophy of reticularis zona (+124%, P=0.00) while glomerulosa and fasciculata zona exhibited only small height variations. Important increases were also observed in the cell height and nuclear diameter of fasciculata cells (respectively 40.2 and 10.8%; P=0.00) and reticularis cells (respectively 23.0 and 6.6%; P=0.00). Moreover, connective tissue was well developed in the inner reticularis of castrated gerbils suggesting activation of extracellular matrix.

Orchidectomy induced also increases of lipidic droplets especially in the reticularis zona when adrenal and plasma contents of cortisol exhibited non significant decreases (−6.9%; P=0.78 and −30.4%; P=0.26 respectively).

Testosterone replacement, carried out by twice daily injection of enanthate testosterone (75 μg diluted in 40 μl sesame’s oil) during 7 days on 50 days castrated animals, restored adrenal weight as well as all histological parameters but didn’t restore adrenal and plasma contents of cortisol which showed an even more important reduction.

These results showed clearly an inhibitory effect of testosterone on the activity of the adrenal gland in this Saharan rodent. Testosterone could act either directly or by means of its endogenous regulators, such as pituitary ACTH. So, testosterone could be involved, at least in part, in the determinism of the annual variations of the adrenocortical activity and contribute to the adaptation of this species to its arid environment requiring important metabolic adjustments.