Starvation-realimentation overshoot in glycerophosphate acyltransferase in adipose tissue and liver of rats is influenced by type of dietary fat

Abstract

The purpose of this study was to determine effects of dietary fat source on changes in glycerophosphate acyltransferase that occur with starvation-realimentation. Forty male Sprague-Dawley rats were randomly assigned to dietary treatments at 209 ± 3 g of body weight. Ten rats each were assigned to a 65 g/100 g sucrose diet that contained 5 g/100 g fat from the following sources: stearate (42% stearate, 41% oleate): oleate (high-oleate safflower oil); palm oil; or beef tallow. Five rats received free access to their diet for 4 days and five rats were starved for 2 days and then fed for 2 days. Rats were then killed and liver and epididymal adipose tissue dissected and homogenized for glycerophosphate acyltransferase assay. The starvation-realimentation regimen on the stearate diet stimulated adipose tissue glycerophosphate acyltransferase above non-starved controls. Realimentation on high-oleate and high-palmitate diets stimulated liver glycerophosphate acyltransferase most, as well as produced a starvation-realimentation overshoot in steady-state glycerolipid production. Results indicate that ad libitum consumption of diets containing high proportions of stearate after a period of starvation could overshoot liver glycerophosphate acyltransferase to a lesser extent than if the diet contained low proportions of this fatty acid. Diet fatty acid composition had less impact on adipose tissue than liver glycerophosphate acyltransferase activity in rats subjected to starvation-realimentation.