Adrenal function in Angora goats: A comparative study of adrenal steroidogenesis in Angora goats, Boer goats, and Merino sheep

South African Angora goats (Capra aegagrus) are susceptible to stress condi tions, possibly due to adrenal cortex malfunction. Selection for mohair pro duction may reduce adrenal function and decrease corf;isol production. Secr etion of cortisol by the adrenal cortex is essential for the induction of s everal gluconeogenic enzymes that enable animals to survive stressful condi tions, and adrenocortical insufficiency, therefore, precipitates a vulnerab ility to stress. In this study, Angora goats were compared with two breeds generally accepted as hardy, Beer goats (Capra hircus) and Merino sheep (Ov is aries). Adrenal steroidogenesis was studied using subcellular fractions prepared from the adrenal glands of freshly slaughtered animals. Adrenal mi crosomes and mitochondria were incubated with the relevant steroid substrat es, and products were analyzed and quantified with TLC, HPLC, or RIA. Subse quently, the activity of individual enzymes involved in this pathway were f urther investigated. The cytochrome P450 content in the preparations was al so compared. The results from these studies indicated that the activity of the cytochrome P450c17 enzyme in Angora goats differed (P < .01) from that of the other species investigated. This difference may contribute to the ca use of the observed hypoadrenocorticism in Angora goats.