Evidence for physiological coupling of insulin-mediated glucose metabolism and limb blood flow.
We hypothesized that the vasodilation observed during insulin stimulation is closely coupled to the rate of glucose metabolism. Lean (L, n = 13), obese nondiabetic (OB, n = 13), and obese type 2 diabetic subjects (Type 2 DM, n = 16) were studied. Leg blood flow (LBF) was examined under conditions of euglycemic hyperinsulinemia (EH) and hyperglycemic hyperinsulinemia (HH), which produced a steady-state whole body glucose disposal rate (GDR) of approximately 2,000 micromol. m(-2). min(-1). At this GDR, under both conditions, subjects across the range of insulin sensitivity exhibited equivalent LBF (l/min EH: L, 0.42 +/- 0.03; OB, 0.43 +/- 0. 03; Type 2 DM, 0.38 +/- 0.07; P = 0.72 by ANOVA. HH: L, 0.44 +/- 0. 04; OB, 0.39 +/- 0.05; Type 2 DM, 0.41 +/- 0.04; P = 0.71). The continuous relationship between LBF and GDR did not differ across subject groups [slope x 10(-5) l/(micromol. m(-2). min(-1)) by ANOVA. EH: L, 8.6; OB, 9.2; Type 2 DM, 7.9; P = 0.91. HH: L, 4.2; OB, 2.5; Type 2 DM, 4.1; P = 0.77], although this relationship did differ between the EH and HH conditions (P = 0.001). These findings support a physiological coupling of LBF and insulin-mediated glucose metabolism. The mechanism(s) linking substrate delivery and metabolism appears to be intact in insulin-resistant states.
Mather
K
K
Division of Endocrinology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. kmather@iupui.edu
Laakso
M
M
Edelman
S
S
Hook
G
G
Baron
A
A
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D005215:Fasting / Q000502:physiology; D015309:Glucose Clamp Technique; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D006946:Hyperinsulinism / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007328:Insulin / Q000008:administration & dosage*; D007333:Insulin Resistance / Q000502:physiology; D007866:Leg / Q000098:blood supply; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism; D009765:Obesity; D012039:Regional Blood Flow / Q000187:drug effects* / Q000502:physiology
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin