Fat feeding decreases insulin responsiveness of adipose tissue lipoprotein lipase

The acute effect of fat feeding on the insulin-mediated stimulatory response of adipose tissue lipoprotein lipase (ATLPL) was examined in normal-weight subjects. After two days of isocaloric-formula feeding, subjects were divided into the following four groups: intravenous (IV) saline alone (sal) (n = 5), IV saline and 67 g of oral corn oil ingested at the outset of the infusion (sal/fat) (n = 5), IV insulin (40 mU/m2/min) and glucose to maintain euglycemia (ins/glu) (n = 9), and IV insulin and glucose and oral corn oil (ins/glu/fat) (n = 8). Triglycerides fell less in the ins/glu/fat group than in the ins/glu group (0 +/- 8% v 35 +/- 5%, means +/- SEM, at three hours, P less than 0.01; 15 +/- 8% v 43 +/- 6% at six hours, P less than 0.02). ATLPL in the sal and sal/fat groups did not change during the six-hour period. When the responsiveness of ATLPL was compared between ins/glu/fat subjects and ins/glu subjects, decreases were seen at both three and six hours (-0.3 +/- 3.0 v 15.1 +/- 5.4 nEq/g/min, P less than 0.05; 6.7 +/- 2.7 v 27.9 +/- 3.9 nEq/g/min, P less than 0.001). The glucose infusion rates needed to maintain euglycemia were also decreased by fat feeding, 229 +/- 18 v 287 +/- 20 mg/m2/min (P less than 0.05). Thus, fat feeding with insulin and glucose infusions diminishes the insulin responsiveness of ATLPL.(ABSTRACT TRUNCATED AT 250 WORDS)