EFFECT OF INTRAVENOUS ADMINISTRATION OF APOLIPOPROTEIN A-IV ON PATTERNS OF FEEDING, DRINKING AND AMBULATORY ACTIVITY OF RATS

To characterize the anorectic effect of apolipoprotein A-IV (apo A-IV) , we examined the effect of apo A-IV on the patterns of feeding, drink ing and ambulation of rats fed ad libitum. A single dose of 200, 135 o r 60 mug was infused intravenously through a chronically indwelling ri ght atrial catheter just before the dark period. Apo A-IV suppressed f ood intake by decreasing meal size, but did not affect the interval be tween meals, the speed of eating, or the latency to eat the first meal after infusion. The anorectic effect of apo A-IV was dose-dependent a nd was effective for about 3 h after the infusion. The anorectic effec t of apo A-IV is specific because inactivation of apo A-IV abolishes i ts anorectic effect. The anorectic effect of apo A-IV is not shared by apo A-I. Apo A-IV had no effect on drinking behavior or ambulatory ac tivity. The results seem to indicate that apo A-IV specifically decrea ses the meal size, which supports our hypothesis that apo A-IV may act as a physiological signal for satiation after the ingestion of a lipi d meal.