Hepatic ketogenesis and gluconeogenesis in humans.
Splanchnic arterio-hepatic venous differences for a variety of substrates associated with carbohydrate and lipid metabolism were determined simultaneously with hepatic blood flow in five patients after 3 days of starvation. Despite the relative predominance of circulating beta-hydroxybutyrate, the splanchnic productions of both beta-hydroxybutyrate and acetoacetate were approximately equal, totaling 115 g/24 h. This rate of hepatic ketogenesis was as great as that noted previously after 5-6 wk of starvation. Since the degree of hyperketonemia was about threefold greater after 5-6 wk of starvation, it seems likely that the rate of ketone-body removal by peripheral tissues is as important in the development of the increased ketone-body concentrations observed after prolonged starvation as increased hepatic ketone-body production rate. Splanchnic glucose release in this study was 123 g/24 h, which was less than that noted previously after an overnight fast, but was considerably more than that noted during prolonged starvation. Hepatic gluconeogenesis was estimated to be 99 g/24 h, calculated as the sum of lactate, pyruvate, glycerol, and amino acid uptake. This was greater than that observed either after an overnight fast or after prolonged starvation. In addition, a direct relationship between the processes of hepatic ketogenesis and gluconeogenesis was observed.
D000090:Acetoacetates / Q000097:blood; D001786:Blood Glucose; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D002404:Catheterization; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005943:Gluconeogenesis; D006503:Hepatic Veins; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D007657:Ketone Bodies / Q000097:blood / Q000378:metabolism*; D007773:Lactates / Q000097:blood; D008099:Liver / Q000378:metabolism*; D008102:Liver Circulation; D010100:Oxygen / Q000097:blood; D013217:Starvation / Q000097:blood
D000090:Acetoacetates; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D006885:Hydroxybutyrates; D007657:Ketone Bodies; D007773:Lactates; D002245:Carbon Dioxide; D010100:Oxygen