The relationship of the splanchnic, hepatic and renal clearance rates to the metabolic clearance rate of cortisol in conscious sheep.

Abstract

SUMMARY The uptake of cortisol by organs in the splanchnic area of conscious, undisturbed sheep was estimated before and during the administration of adrenocorticotrophic hormone (ACTH) by measuring cortisol concentration differences in portal and hepatic venous plasma and estimating hepatic plasma flow rates. Metabolic clearance rates (MCR) of plasma cortisol were measured simultaneously. The total splanchnic clearance of cortisol was 61% of MCR in the animal, 48% being accounted for by the liver. When ACTH was given there were increases in MCR and these were accompanied by proportional increases in hepatic plasma flow rates. When ACTH was infused the total splanchnic clearance rate was 65% of MCR, 52–59% being accounted for by the liver. In other experiments the renal clearance rate of cortisol was studied. Under control conditions, and when ACTH was given, the renal clearance was 11% of MCR. The relationship of the sum of individual clearances to MCR is compared and discussed.