Conversion of glycerol to glucose in the normal dog.

WINKLER, B., I. KATHGEB, R. STEELE, AND N. ALTSZULER. Conversion of glycerol to glucose in the normal dog. Am. J. Physiol. 219(2) : 497-502. 1970.-Rates of conversion of blood glycerol carbon to blood glucose carbon, a process carried out by the liver, were measured in unanesthetized dogs in the postabsorptive state. The calculation of the rates required knowledge of the separate rates of glucose and glycerol turnover; those were measured with glucose-6l*C and glycerol-U-l*C, infused intravenously in trace amounts. When both tagged compounds were used simultaneously, two separate derivatives of plasma glucose were prepared in order to differentiate between l*C arising from infused glucose-6J4C and l*C arising from the conversion of glycerol to glucose. Uptake of glycerol from the plasma at the mean concentration (postabsorptive state) of 0.12 mM was 7.6 mmoles/m2 body surface area per hr. Of the glycerol carbon taken up, 34y0 was returned promptly to the blood as glucose carbon; this accounted for 6.30/, of the total glucose carbon released to the blood. When bulk glycerol was infused to increase (up to fourfold) the normal glycerol uptake rate, the rate of glucose release did not increase; about the same fraction as before of the glycerol carbon taken up was converted to glucose carbon, but this now accounted for up to 30y0 of the total glucose carbon released.