Lipolytic activities of p-aminophenol and n-decylamine in endogenous lipid droplets from rat adipocytes

Lipolytic agents such as adrenaline (epinephrine), dibutyryl cyclic AMP (DBcAMP) and theophylline possess common structural characteristics, the existence of a positive charge and a hydrophobic area. p-Aminophenol, which has the same structural characteristics, was found to induce lipolysis in the endogenous lipid droplets from rat adipocytes. It was demonstrated that the positive group and the hydrophobic area of p-aminophenol are essential requirements for its lipolytic activity. Among various amine derivatives, only n-decylamine was found to induce lipolysis in the endogenous lipid droplets. Although the lipolytic action of n-decylamine is fairly low, it possesses remarkable inhibitory effects on both adrenaline- and DBcAMP-induced lipolytic activities. Furthermore, n-decylamine is found to inhibit competitively the DBcAMP-induced lipolysis.