Acetoacetate formation by liver slices from adult and infant rats

Abstract

Acetoacetate formation by liver slices from young (0-23-day-old) and adult (90-day-old) rats was studied. The rate of endogenous acetoacetate formation at birth is the same as in adult rats, i.e. 2.5 [mu]moles/g. wet wt./hr. It is raised to 10.2 [mu]moles/ g. wet wt./hr. within 24 hr. of birth and remains elevated beyond day 10. A 24 hr. period of starvation increases the rate of acetoacetate formation by 120% in 90-day-old rats and by only 20% in 10-day-old rats, yet acetoacetate formation is still twice as great in the infant rats. Palmitate or acetate raises the rate of acetoacetate formation in both 10-day-old and 90-day-old fed or starved rats. In all cases the rate of acetoacetate formation is higher in the infant rats. Succinate elevates the respiration rate and decreases the endogenous formation of acetoacetate in both age groups. The blood concentration of acetoacetate increases within 24 hr. of birth and remains elevated beyond day 10, after which it decreases again. The results are discussed in relation to the character of the diet of infant and adult rats.