Carbohydrate and lipid metabolism in cockroach (Periplaneta americana) fat body are both activated by low and similar concentrations of Peram-AKH II.

Injection of 0.1 pmol of the octapeptide Peram-AKH II (pGlu-Leu-Thr-Phe-Thr-Pro-Asn-TrpNH(2)) elicits a significant hypertrehalosemic response in the American cockroach, Periplaneta americana; a maximal effect is obtained with 1pmol. The latter amount also lowers the level of neutral lipid (NL) and phospholipid (PL) in the hemolymph. The evidence supports the idea that Peram-AKH II promotes the liberation of fatty acids from hemolymph phospholipid, and indirectly diacylglycerol in the same compartment. The fatty acids are then transported into the fat body where they are converted into triacylglycerol for storge. Because lipolysis and trehalose synthesis are initiated by a common concentration of Peram-AKH II it is reasonable to suggest that the physiological function of Peram-AKH II involves the participation of both metabolic pathways.