The excretion of metabolites of testosterone and of estradiol in male patients with chronic renal failure.

Intravenous infusions of 14C-testosterone (Te) either alone or in combination with 3H-estradiol (E2) were given to five normal male subjects, twelve male patients on haemodialysis (HD) treatment and to one patient with a very restricted renal function. The elimination of radioactivity was measured in urine, HD fluid and faeces. Urinary excretion diminished with renal function. It was negligible at a creatinine clearance of less than one ml per minute. A quarter of both isotopes was eliminated by six HD treatments within three weeks. No difference was found in this respect between nephrectomized patients and those who were still in possession of their kidneys. The main excretion occurred in the stools. E2 metabolites, and to a lesser extent Te metabolites, appeared in the faeces within 24 hours, which might be explained by biliary excretion only. More 3H (E2 metabolites) than 14C (Te metabolites) was found in the faeces; more 14C than 3H found in HD fluid.