The Effect of a Sucrose-Enriched Diet on the Metabolism of Intravenously Administered Fructose in Baboons

Abstract

There is a highly significant rise in the fasting serum glyceride concentrations of both male and female baboons in the first 3 weeks of consumption of a 75-ρercent by weight sucrose diet, reaching a peak between the 2nd and 4th weeks of the diet. Even at 10 weeks the mean values are higher than the pre-diet levels. There is no significant change in the fasting cholesterol or phospholipid concentrations. There is no detectable change in the overall rate of fructose metabolism when fructose is given intravenously at the end of the high sucrose diet as compared with before the diet. There is no significant change in the glyceride ¹⁴C-specific activity following intravenous injection of ¹⁴C-fructose at the end of the dietary period as compared with the beginning in either male or female baboons. This suggests that if there has been overall increase in the rate of glyceride synthesis this has not occurred solely as a result of a selective conversion of fructose to glyceride, but involves all glyceride precursor substances. The pattern of change in serum lipid and glucose concentrations following fructose injection is no different at the end of the dietary period compared with the beginning. There is a suggestion of increased glucose assimilation during the dietary period. It is concluded that the increase in incorporation into the serum glyceride of ¹⁴C-sucrose given orally at the end of a period of consuming 75% sucrose is primarily due to an increased rate of absorption of the products of sucrose hydrolysis rather than to any increase in the rate of metabolism of fructose.