One hypophysectomized-pancreatectomized dog showed no spontaneous glycosuria. Marked glycosuria was produced by the injection of extract of anterior lobe; less by whole gland extract; and none by obstetrical pitui-trin. The dog was sensitive to insulin. Seven normal dogs showed glycosuria when injected with anterior lobe extract; 4 others showed no effect. Six thyroidecto-mized dogs showed no glycosuria when injected with these extracts. Four normal dogs showed increased sensitivity to insulin after receiving amniotin, and 2 of these dogs, pancreatectomized while receiving amniotin, did not show severe glycosuria.