TY - JOUR
T1 - Microvascular recruitment is an early insulin effect that regulates skeletal muscle glucose uptake in vivo
AU - Vincent, Michelle A.
AU - Clerk, Lucy H.
AU - Lindner, Jonathan R.
AU - Klibanov, Alexander L.
AU - Clark, Michael G.
AU - Rattigan, Stephen
AU - Barrett, Eugene J.
PY - 2004/6
Y1 - 2004/6
N2 - Insulin increases glucose disposal into muscle. In addition, in vivo insulin elicits distinct nitric oxide synthase-dependent vascular responses to increase total skeletal muscle blood flow and to recruit muscle capillaries (by relaxing resistance and terminal arterioles, respectively). In the current study, we compared the temporal sequence of vascular and metabolic responses to a 30-min physiological infusion of insulin (3 mU · min-1 · kg-1, euglycemic clamp) or saline in rat skeletal muscle in vivo. We used contrast-enhanced ultrasound to continuously quantify microvascular volume. Insulin recruited microvasculature within 5-10 min (P < 0.05), and this preceded both activation of insulin-signaling pathways and increases in glucose disposal in muscle, as well as changes in total leg blood flow. Moreover, L-NAME (Nω-nitro-L-arginine-methyl ester), a specific inhibitor of nitric oxide synthase, blocked this early microvascular recruitment (P < 0.05) and at least partially inhibited early increases in muscle glucose uptake (P < 0.05). We conclude that insulin rapidly recruits skeletal muscle capillaries in vivo by a nitric oxide-dependent action, and the increase in capillary recruitment may contribute to the subsequent glucose uptake.
AB - Insulin increases glucose disposal into muscle. In addition, in vivo insulin elicits distinct nitric oxide synthase-dependent vascular responses to increase total skeletal muscle blood flow and to recruit muscle capillaries (by relaxing resistance and terminal arterioles, respectively). In the current study, we compared the temporal sequence of vascular and metabolic responses to a 30-min physiological infusion of insulin (3 mU · min-1 · kg-1, euglycemic clamp) or saline in rat skeletal muscle in vivo. We used contrast-enhanced ultrasound to continuously quantify microvascular volume. Insulin recruited microvasculature within 5-10 min (P < 0.05), and this preceded both activation of insulin-signaling pathways and increases in glucose disposal in muscle, as well as changes in total leg blood flow. Moreover, L-NAME (Nω-nitro-L-arginine-methyl ester), a specific inhibitor of nitric oxide synthase, blocked this early microvascular recruitment (P < 0.05) and at least partially inhibited early increases in muscle glucose uptake (P < 0.05). We conclude that insulin rapidly recruits skeletal muscle capillaries in vivo by a nitric oxide-dependent action, and the increase in capillary recruitment may contribute to the subsequent glucose uptake.
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U2 - 10.2337/diabetes.53.6.1418
DO - 10.2337/diabetes.53.6.1418
M3 - Article
C2 - 15161743
AN - SCOPUS:2542539954
SN - 0012-1797
VL - 53
SP - 1418
EP - 1423
JO - Diabetes
JF - Diabetes
IS - 6
ER -