Hepatic Glucose Production and Splanchnic Glucose Exchange in Hyperthyroidism

Hepatic glucose production (HGP) and net splanchnic glucose balance (NSGB) were simultaneously determined in the basal state in 8 hyperthyroid patients and 10 normal subjects using ivinfusion of [3H]3-glucose and the hepatic venous catheter technique. Splanchnic glucoseuptake (SGU) was calculated as the difference between the HGP and NSGB. SGU was also measured by determining the splanchnic extraction ratio of [3H]3-glucose across the splanchnic bed. In 5 hyperthyroid patients and 5 normal subjects a renal vein was also catheterized in the basal state. The influence of increased endogenous insulin secretion [stimulated by a low rate iv infusion of glucose (2 mg⁄kg-min)] on splanchnic and hepatic glucose exchange was also examined. Basal HGP (measured with [3H]3-glucose) was increased by 20% in the hyperthyroid patients [14.2 ± 0.6 (SEM) μmol/;kgmin] as compared to normal subjects (11.9 ± 0.6, P < 0.02). In marked contrast, NSGB output was slightly but not significantly decreased in the hyperthyroid group....