RENAL FUNCTION FOLLOWING HYPOPHYSECTOMY IN MAN

Abstract

Glomerular filtration rate (GFR) and renal plasma flow (RPF), as measured by clearances of inulin and para-aminohippuric acid, were studied before and after hypophysectomy in 23 patients (9 cases of metastatic mammary carcinoma, 9 cases of diabetes mellitus with retinopathy, and 5 cases of acromegaly). In 12 of the patients, the maximal rate of tubular excretion of para-aminohippuric acid (TrnPAH) was also studied. All subjects developed evidence of depressed adrenocortical function after hypophysectomy and were on replacement therapy with cortisone (17,21-dihydroxy-pregn-4-ene-3,ll,20-trione) at the time of the postoperative studies. In 4 cases, postoperative hypothyroidism was not demonstrated. In all patients, GFR and RPF decreased after hypophysectomy and this reduction was present within 4 to 8 weeks after surgery, when the first postoperative study was usually performed. In additional studies, at different intervals after hypophysectomy there were, on the whole, only minor further changes in GFR and RPF. Thyroid therapy increased GFR and RPF in the hypophysectomized patients but did not raise the values to the preoperative level. Following hypophysectomy TmPAH decreased in 9 of the 12 patients studied. Thyroid therapy did not regularly increase the Tm values.