title: Glycerol production and utilization in humans: sites and quantitation.
abstract: Liver is assumed to be the major site of glycerol uptake and fatty acid reesterification. [U-13C]glycerol was infused into ten 60 h-fasted healthy subjects. Measured were 1) blood glycerol concentrations and 13C enrichments in brachial and pulmonary arteries and in hepatic, renal, superficial, and deep forearm veins; 2) glycerol appearance rates in systemic circulation; and 3) splanchnic bed and kidney glycerol uptakes with use of balance and tracer methodology. Glycerol concentrations were one-fifth in hepatic, one-half in renal, 40% more in superficial, and the same in deep vein and pulmonary artery as in brachial artery blood. Glycerol enrichments were one-fifth in hepatic, two-thirds to three-quarters in renal and superficial veins, and the same in pulmonary as in brachial artery blood. Splanchnic glycerol uptake was 29% and kidney glycerol uptake was 17% of glycerol's rate of appearance, 5.11 mumol.min-1.kg-1. Splanchnic fatty acid uptake was 25% of calculated fatty acid release. Glycerol contributed 15% to glucose production. Most of the [13C]glycerol uptake by splanchnic bed and kidneys was incorporated into glucose. Thus, in 60 h-fasted individuals, most glycerol uptake does not occur in liver, and the extent of fatty acid reesterification in liver is in doubt.
authors.affiliation: Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Landau
authors.forename: J
authors.initials: J
authors.lastname: Wahren
authors.forename: S F
authors.initials: SF
authors.lastname: Previs
authors.forename: K
authors.initials: K
authors.lastname: Ekberg
authors.forename: V
authors.initials: V
authors.lastname: Chandramouli
authors.forename: H
authors.initials: H
authors.lastname: Brunengraber
mesh_terms: D000328:Adult; D001835:Body Weight; D005990:Glycerol / Q000378:metabolism*; D006801:Humans; D008297:Male; D009928:Organ Specificity; D012039:Regional Blood Flow
chemical_list: D005990:Glycerol