Human follicle- stimulating hormone modulation of adrenal gland activity in the Italian crested newt, Triturus carnifex (Amphibia, Urodela)

ABSTRACT The aim of the present study was to verify if human FSH influences the adrenal gland of the newt, Triturus carnifex. Newts were given intraperitoneal injections of human FSH throughout the periods of February–March, and December–January; periods in which newt FSH levels are normally very low. The effects of human FSH on adrenal gland activity were observed in the morphological features of the steroidogenic and chromaffin adrenal cells, and in the serum levels of aldosterone, corticosterone, norepinephrine and epinephrine. The effect of human FSH on the steroidogenic cells was significant during the February–March period; the quantity of cytoplasmic lipids decreased, and the corticosteroid serum levels increased. During the December–January period, the human FSH effects were negligible. The effect of human FSH on the chromaffin cells was significant during both the February–March, and the December–January periods. During February–March, the human FSH increased the numeric ratio of norepinephrine granules to epinephrine granules, and increased the epinephrine serum levels. During December–January, the human FSH decreased the numeric ratio of norepinephrine granules to epinephrine granules, and increased the norepinephrine serum levels. The results of the present study show that human follicle-stimulating hormone influences the activity of the newt adrenal gland, thus indicating a relationship between the annual sexual cycle and the annual adrenal cycle of the newt.