Contributions of liver and kidneys to glycerol production and utilization in the dog
Previs, S.F.; Martin, S.K.; Hazey, J.W.; Soloviev, M.V.; Keating, A.P.; Lucas, D.; David, F.; Koshy, J.; Kirschenbaum, D.W.; Tserng, K.Y.; Brunengraber, H.
American Journal of Physiology 271(6 Pt 1): E1118-E1124
1996
ISSN/ISBN: 0002-9513 PMID: 8997233 Document Number: 465077
The classical concept holds that liver and kidneys are the main sinks of glycerol released by adipose tissue. However, rates of glycerol appearance (R-a) exceed the rate of glycerol delivery to liver and kidneys. We measured the hepatic and renal contributions to glycerol production and utilization in anesthetized dogs that were fasted either overnight or for 24 h after 3 days on a carbohydrate-free diet. Dogs were infused with (2H-5)glycerol, and the concentration and 2H enrichment of glycerol were measured across liver and kidney. After a baseline period, either norepinephrine or glucose plus insulin was infused to alter the rate of glycerol production. Our study shows that the production of glycerol by liver and kidneys amounted to 4-9% and 4-7% of the R-a of glycerol, respectively. Uptake of glycerol by liver and kidneys amounted to 26-30 and 10-19% of the R-a of glycerol, respectively. Thus, contrary to the classical concept, the bulk of glycerol utilization occurs in nonhepatic, nonrenal tissues that have very low glycerol kinase activity per gram.