title: Glucose transport in human skeletal muscle. The in vivo response to insulin.
abstract: Transmembrane glucose transport plays a key role in determining insulin sensitivity. We have measured in vivo WBGU, FGU, and K(in) and K(out) of 3-O-methyl-D-glucose in forearm skeletal muscle by combining the euglycemic clamp technique, the forearm-balance technique, and a novel dual-tracer (1-[3H]-L-glucose and 3-O-[14C]-methyl-D-glucose) technique for measuring in vivo transmembrane transport. Twenty-seven healthy, lean subjects were studied. During saline infusion, insulin concentration, FGU (n = 6), K(in), and K(out) (n = 4) were similar to baseline. During SRIF-induced hypoinsulinemia (insulin < 15 pM, n = 4) WBGU was close to 0, and FGU, K(in), and K(out) were unchanged from basal (insulin = 48 pM) values. During insulin clamps at plasma insulin levels of approximately 180 (n = 4), approximately 420 (n = 5), approximately 3000 (n = 4), and approximately 9500 pM (n = 4), WBGU was 14.2 +/- 1.3, 34.2 +/- 4.1 (P < 0.05 vs. previous step), 55.8 +/- 1.8 (P < 0.05 vs. previous step), and 56.1 +/- 6.3 mumol.min-1.kg-1 of body weight (NS vs. previous step), respectively. Graded hyperinsulinemia concomitantly increased FGU from a basal value of 4.7 +/- 0.5 mumol.min-1.kg-1 up to 10.9 +/- 2.3 (P < 0.05 vs. basal value), 26.6 +/- 4.5 (P < 0.05 vs. previous step), 54.8 +/- 4.3 (P < 0.05 vs. previous step), and 61.1 +/- 10.8 mumol.min-1.kg-1 of forearm tissues (NS vs. previous step), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: C.N.R. Institute of Clinical Physiology, University of Pisa, Italy.
authors.forename: R C
authors.initials: RC
authors.lastname: Bonadonna
authors.forename: M P
authors.initials: MP
authors.lastname: Saccomani
authors.forename: L
authors.initials: L
authors.lastname: Seely
authors.forename: K S
authors.initials: KS
authors.lastname: Zych
authors.forename: E
authors.initials: E
authors.lastname: Ferrannini
authors.forename: C
authors.initials: C
authors.lastname: Cobelli
authors.forename: R A
authors.initials: RA
authors.lastname: DeFronzo
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001692:Biological Transport / Q000187:drug effects; D001786:Blood Glucose / Q000378:metabolism*; D005542:Forearm; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology* / Q000502:physiology*; D007700:Kinetics; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D012016:Reference Values; D013004:Somatostatin / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D007328:Insulin; D013004:Somatostatin; D005947:Glucose