Ultrasonographic examination of the adrenal gland and evaluation of the hypophyseal-adrenal axis in 20 cats

The adrenal glands of 20 healthy, non-sedated cats were examined ultrasonog raphically; visualisation and assessment was possible in all cases. In comp arison with the surrounding tissue, the adrenal glands were hypoechoic and two distinct zones could be differentiated in six of the cats. The length a nd width of the adrenal glands varied from 0.45 to 1.37 cm and 0.29 to 0.53 cm, respectively, and both dimensions could be reliably reproduced. The ad renal glands did not differ between male and female cats, and, in compariso n to dogs, those of cats are more easily visualised ultrasonographically. T he basal cortisol value ranged from 2.0 to 79 mu g/litre. Values 30 and 60 minutes after administration of ACTH (0.125 mg/cat intramuscularly) varied from 36 to 126 mu g/litre. The basal value of aldosterone ranged from 4 to 618 pg/ml. Values 30 and 60 minutes after administration of ACTH varied fro m 100 to 832 pg/ml, In all cats, suppression of the cortisol value below th e level of detection (<2.0 mu g/litre) occurred four and eight hours after the administration of dexamethasone (0.1 mg/kg intravenously).