Studies on the carbohydrate metabolism of skin

Abstract

The respiration and glucose utilization of skin of the guinea pig ear in vitro are unaffected by the glucose concentration within the range 0.005-0.02 [image] The respiration and fructose utilization increase as the fructose concentration is increased. In glucose-fructose mixtures the utilization of fructose is reduced, the glucose utilization is unaffected and the total hexose utilization thus increases. This is not reflected in an increased respiration rate. In the absence of serum the glucose utilization is only about 1/2 of that occurring in the presence of serum, and the respiration is only slightly reduced; the sum of lactic acid produced and the calculated glucose oxidized equals the observed glucose utilized. Glucose, fructose, lactate and pyruvate stimulate respiration and maintain a relatively high respiration rate for 24 hours. Succinate, malate and acetate stimulate respiration but permit a gradual decline over 24 hours. Oxalacetate maintains respiration for 5 hours only, subsequently becoming toxic; fumarate also stimulates respiration initially but its effect declines between 5 and 24 hours. Citrate causes transitory stimulation in the first hour and [alpha]-ketoglutarate is without effect. Glucose 1-phosphate causes initial depression, but at 24 hours a slight increase over the control occurs. These findings are discussed in relation to the carbohydrate metabolism of skin.