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Glycogen concentration in human skeletal muscle: effect of prolonged insulin and glucose infusion
Author(s) -
Hansen B. F.,
Asp S.,
Kim B.,
Richter E. A.
Publication year - 1999
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.1999.tb00235.x
Subject(s) - glycogen , medicine , endocrinology , insulin , ingestion , carbohydrate , skeletal muscle , chemistry
To study the upper limit of glycogen storage in human muscle, two healthy male subjects were infused with glucose and insulin for 8 h reaching plasma concentrations of about 21 mM glucose and approximately 2000 μU/ml insulin. Prior to the infusion subjects performed for 1 h one‐legged knee‐extensor exercise at 75% of their maximum one‐legged work capacity in order to lower muscle glycogen stores in one leg. During the 8‐h hyperglycemic clamp procedure, glycogen concentrations increased and levelled off at 2‐ and 5‐fold above the pre‐infusion levels in the resting and the working leg, respectively. However, the absolute glycogen levels reached in both legs were quite similar, close to 4 g per 100 g wet muscle (about 1000 μmol/g d.w.), independent of prior exercise. Previous studies have shown that glycogen levels, after a bout of glycogen‐depleting exercise and subsequent ingestion of a carbohydrate‐rich diet for 3 days, can be increased to values around 3–4 g per 100 g wet muscle. It appears that the maximal attainable glycogen concentration in human muscle seems to be close to 4 g per 100 g wet muscle. This glycogen level can thus be reached either by a prolonged infusion of supra‐physiological concentrations of glucose and insulin or by glycogen‐depleting exercise followed by ingestion of a carbohydrate‐rich diet.