Effects of Insulin on Glucose Transport in Chick Embryo Heart
Previous studies on glucose uptake by chick embryo hearts [1, 2] indicated that the permeability of the cardiac cell for glucose changes during ontogeny. In particular, it was suggested that in the early stages of embryological development, glucose enters the cell freely, and its uptake is limited by the rate of intracellular utilization. At this stage, the preparation is insensitive to insulin. Between the 6th and the 9th day of development, a glucose transport system develops and becomes the rate limiting factor of glucose uptake. This system appears to be sensitive to insulin and to other substances, such as 2,4-dinitrophenol and ouabain, which are known to alter membrane permeability [3, 4]. Accordingly, as the development of the heart proceeds, the preparation becomes progressively less permeable to sorbitol, a glucose analogue that does not penetrate the cardiac cell in the adult rat heart .
KeywordsGlucose Uptake Glucose Transport Cardiac Cell Embryological Development External Concentration
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