Effect of food deprivation on rat plasma estrone fatty acid esters

The present study was devised to determine whether the circulating levels o f estrone fatty esters are modified by 6-48 h starvation in the rat, in par allel to changes in fat reserves, as a test to check the plausibility of it s function as a ponderostat signal in the mammal. Food deprivation resulted in a decrease in glucose and triacylglycerols, rapid disappearance of live r glycogen and increases in fatty acids and, especially, 3-hydroxybutyrate. Insulin and leptin decreased, corticosterone and free estrone increased fr om 6 h onwards and total estrone levels were maintained. Starvation reduced the lipid content of the rat by 25.6%. Plasma esterified estrone levels de creased more slowly, by 13% in 48 h, but its circulating mass decreased in the same proportion as the total lipid content of the rat. The small change in circulating estrone fatty esters is consistent with the postulated role of oleoyl-estrone as a medium-term ponderostat signal.