Further studies on the entry rates of acetate and glucose in sheep, with special reference to endogenous production of acetate

Abstract

The rates of entry of glucose and acetate in fed and starved sheep were measured simultaneously by the constant infusion of labelled glucose and labelled acetate. The entry of acetate after feeding was sufficiently constant to allow measurement of entry rates only during the period when a maximum concentration of rumen acetate was attained, which presumably coincided with maximum production and absorption of acetate. The entry of endogenous acetate in sheep with emptied rumens was 40-50% of the value for the total entry of acetate obtained in the same animals after feeding. Under conditions of normal acetate absorption, the entry of endogenous acetate accounted for about 25% of the total entry. Raised concentrations of blood glucose or acetate reduced the entry of endogenous acetate in sheep with emptied rumens, or in starved sheep. These results were consistent with the hypothesis that the oxidation of free fatty acids contributes substantially to the entry of endogenous acetate in sheep.