SOME ENDOCRINE INFLUENCES ON RENAL FUNCTION AND CARDIAC OUTPUT

Abstract

Thyroidectomy in dogs produces some fall in diodrast (D) clearance and the maximum tubular excretion of diodrast (D Tm), with little or no effect on inulin clearance; the effects are far less than those of hypophysectomy. Thyroid admn. to thyroidec-tomized dogs raises D clearances and D Tm. Anterior lobe admn. which gives large increases in these clearances and in D Tm in the normal or the hypophysectomized dog produces small and inconsistent rises in the thyroidectomized dog. Bilateral ovariectomy does not affect D or inulin clearances or D Tm. Very mild adrenal insufficiency, asymptomatic and with normal blood vol. and NPN, Na and K plasma levels, may cause large falls in D clearance and D Tm, with smaller fall in inulin clearance. Values were restored to normal by implantation of pellets of desoxycorticosterone acetate, which were more effective than was daily subcut. admn. of DCA and ACE. The asymptomatic adrenal deficient dog does not respond to ant. lobe admn. with increases in clearances and D Tm, as does the normal or the hypophysectomized dog. The falls in clearance and Tm values seen in hypophysectomy are not due to loss of thyrotrophic or of gonadotrophic hormone, nor to the reduction in O2 consumption per se. The question of whether the effects can be ascribed mainly to loss of adrenotrophic hormone or whether some other deficiencies are operative is left unanswered. The cardiac output is greatly and permanently reduced after hypophysectomy, and to about the same degree as are O2 consumption and renal blood flow.