Yamina Zatra; Naouel Aknoun-Sail; Arezki Kheddache; Abdelouafi Benmouloud2; Asma Chakhma; Farida Khammar; Salima Charallah & Zaina Amirat

We previously reported that the free-living male Gerbillus tarabuli exhibits opposite seasonal variations of the pituitary adrenal axis activity to that of the pituitary gonadal axis, suggesting negative interrelationships between these endocrine functions. So, in this paper we investigate the role of testosterone on pituitary adrenal axis by removing testes during the sexually active period. Gerbils were captured in late winter and early spring in their natural Saharan biotope. The experiment involved three groups of eight adult males (sham-operated control, gonadectomized and testosterone-replaced gonadectomized gerbils). The right adrenal and pituitary glands were quickly taken out from euthanasia performed 30 days after gonadectomy or 7 days after testosterone replacement. Then, they were fixed either for beta-catenin (β-catenin) immunohistochemistry in the adrenal glands using specific β-catenin antibody or double-labelled indirect immunofluorescence for androgen receptors (AR) and ACTH cell detection in the pituitary sections using a rabbit polyclonal anti-AR antibody and a mouse monoclonal antibody against ACTH. In the intact gerbils, AR were found colocalized with ACTH in pituitary corticotroph cells. The adrenocortical immunolocalization of β-catenin was particularly capsular and slightly glomerular, whereas it was absent in the inner zona cortical. After orchiectomy, ACTH cells were less numerous with a weak expression of AR. In the adrenal cortex, castration induced a strong β-catenin immunoreactivity in the fasciculata and zona reticularis with a centripetally decreasing gradient; b-catenin immunoreactivity disappears completely in the adrenal capsule. Testosterone replacement therapy restores all parameters. These results suggest an inhibitory effect of testosterone on the pituitary-adrenal axis of Gerbillus tarabuli; this steroid could act via a central pathway and locally with an important position of canonical Wnt/β-catenin signaling in order to preserve adrenal cortex zonation and homeostasis throughout the year in this seasonally breeding Saharan rodent.

KEY WORDS: Saharan gerbil; Adrenal homeostasis; ACTH cells; β-catenin; Androgen dependency

ZATRA, Y; AKNOUN-SAIL, N.; KHEDDACHE, A.; BENMOULOUD, A.; CHAKHMA, A.; KHAMMAR, F.; CHARALLAH, S. & AMIRAT, Z. Androgen Dependency of the pituitary-adrenal axis in the gerbil Gerbillus tarabuli (Thomas, 1902) living in the Algerian Sahara desert. Int. J. Morphol., 43(4):1214-1222, 2025.