A comparison of the effects of IGF-I and insulin on glucose metabolism, fat metabolism and the cardiovascular system in normal human volunteers |
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Authors: | D. L. RUSSELL-JONES A. T. BATES A. M. UMPLEBY T. R. HENNESSY S. B. BOWES K. D. HOPKINS N. JACKSON J. KELLY F. SHOJAEE-MORADIE R. H. JONES P. H. SONKSEN |
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Affiliation: | Division of Medicine, United Medical and Dental School of Guy's and St Thomas' Hospitals, St Thomas' Hospital, London, UK |
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Abstract: | Abstract. The metabolic and cardiovascular effects of recombinant human IGF-I were compared to insulin in six normal subjects. Subjects were studied twice and intravenously received an infusion of [6,6-2H2]glucose (0–480 min) and in random order either IGF-I 20μg kg-1 h-1 (43.7 pmol kg-1 min-1) or insulin 0.5 mU kg-1 min-1 (3.4 pmol kg-1 min-1) with an euglycaemic clamp. One subject was withdrawn following a serious adverse event. During the IGF-I infusion glucose appearance rate (Ra) decreased from 1.79 ± 0.13 at baseline (150–180 min) to 0.35 ± 0.26 mg kg-1 min-1 ( P < 0.01) at 360min, and glucose utilization rate (Rd) increased from 1.79 ± 0.28 to 4.17 ± 0.84 mg kg-1 min-1 ( P < 0.01). There was no change in free fatty acids (FFA) and an increase (percentage change from pre-infusion mean) in cardiac output + 37.3%± 9% ( P < 0.01), heart rate + 13%± 2% ( P < 0.01) and stroke volume + 21%± 7% ( P < 0.05). During the insulin infusion glucose Ra decreased from 1.89 ± 0.13 to 0.34 ± 0.33 mg kg-1 min-1 ( P < 0.01) and FFA from 0.546 mmoll-1 to 0.198 mmoll-1 ( P < 0.01), glucose Rd increased from l.89 ± 0.18 to 5.41 ± l.47mg kg-1 min-1 ( P < 0.01) and there were no significant changes in the cardiovascular variables. |
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Keywords: | Cardiac output glucose metabolism heart rate IGF-I insulin stroke volume |
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