Effect of mitotane therapy on adrenal gland size in dogs with pituitary dependent hyperadrenocorticism - an ultrasonographic study

The effect of mitotane therapy on adrenal gland size was evaluated in 13 do gs with pituitary dependent hyperadrenocorticism. Ultrasonographic measurem ents were obtained before and during mitotane therapy. During therapy both adrenal glands were shorter and thinner (median during therapy: left adrena l gland 19.4 mm long, 5.4 mm thick, right adrenal gland 18.1 mm long, 6.1 m m thick) than before mitotane therapy (median before therapy: left adrenal gland 23.6 mm long, 8.3 mm thick, right adrenal gland 21.6 mm long, 8.1 mm thick). Statistical evaluation showed a significant reduction in size. But ultrasonographic measurement of adrenal gland size is not useful in the eva luation of adrenal reserve during mitotane therapy. Inadequate adrenal rese rve was not identified and adrenal size measurement by ultrasonography was not helpful to differentiate adequate and inadequate control of adrenal cor tisol secretion during mitotane therapy.