i.c.v. palmitic acid (but not oleic acid) attenuates insulin-induced suppression of hepatic glucose production.
Rats (6–8/group) received a 3-day i.c.v. infusion of palmitic acid, oleic acid, or control (cont) (PBS), before a carotid-artery insulin infusion under euglycemic clamp conditions. Comparable glucose use rates (~100 mg/dl) were achieved in all groups, beginning 90 minutes after the start of the experiment. All groups had plasma insulin values of approximately 900 pmol/l (data not shown). Carotid insulin infusions reduced hepatic glucose production in control and oleic acid–infused rats but not in rats infused with palmitic acid (data are mean ± SEM; ***