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Insulin and contraction increase nutritive blood flow in rat muscle in vivo: determined by microdialysis of L-[14C]glucose

journal contribution
posted on 2023-05-16, 20:56 authored by Newman, JMB, Renee RossRenee Ross, Stephen RichardsStephen Richards, Michael ClarkMichael Clark, Stephen RattiganStephen Rattigan
In the present study, a mathematical model using the microdialysis outflow: inflow (O/I) ratio of the novel analogue L-[14 C]glucose has been developed which allows the calculation of the nutritive (and non-nutritive) flow in muscle as a proportion of total blood flow. Anaesthetized rats had microdialysis probes carrying L[14C]glucose inserted through a calf muscle group (tibialis/ plantaris/gastrocnemius). The nutritive fraction of total blood flow was determined under basal conditions and in response to contraction (electrical field stimulation), insulin (hyperinsulinaemic euglycaemic clamp with 10 mU min-1 kg-1 insulin) or saline control from limb blood flow and the microdialysis O/I ratio of L[14C]glucose. Both contraction and insulin infusion decreased the O/I ratio of L[14C]glucose and increased total limb blood flow. Calculations based on mathematical models using L[14C]glucose O/I and limb blood flow revealed that during basal conditions, the nutritive fraction of total flow was 0.38 ± 0.06, indicating that basal flow was predominantly non-nutritive. Contraction and insulin increased the nutritive fraction to 0.82 ± 0.24 (P < 0.05) and 0.52 ± 0.12 (P < 0.05). Thus the increase in limb blood flow from insulin was fully accommodated by nutritive flow, while contraction increased nutritive flow at the expense of non-nutritive flow. This novel method using microdialysis and the O/I ratio of L[14C]glucose allows the determination of the nutritive fraction of total flow in muscle as well as the proportion of total flow that may be redistributed in response to contraction and insulin. © 2007 The Authors. Journal compilation © 2007 The Physiological Society.

History

Publication title

Journal of Physiology

Volume

585

Pagination

217-229

ISSN

0022-3751

Department/School

Tasmanian School of Medicine

Publisher

Blackwell Publishing

Place of publication

Oxford

Repository Status

  • Restricted

Socio-economic Objectives

Clinical health not elsewhere classified

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