Adrenalectomy of sheep: a novel technique

A rapid technique for adrenalectomy of sheep was developed. Bilateral adrenalectomy was performed in a single stage operation by inducing ischaemia with latex rings of the type used commonly for the castration of lambs and calves. The success of the technique was demonstrated by failure of exogenous ACTH to increase circulating cortisol concentrations. Adrenal steroid replacement was used to maintain the sheep during the post-operative period (cortisol 0.25 mg.kg-1, deoxycorticosterone acetate 0.05 mg.kg-1). Adrenalectomised sheep were maintained for up to 20 days without glucocorticoid, provided a lowered dose of mineralocorticoid was administered (0.04 mg.kg-1 x day-1). Adrenalectomised sheep had significantly (P < 0.007) lower packed cell volume (23.75%) than normal sheep (31.24%), across a broad range of cortisol concentrations (0 to 734 ng/mL), indicating that plasma cortisol may not reflect true blood concentrations when drawing comparisons between adrenalectomised and normal sheep.