Novel experimental protocol to increase specific plasma nonesterified fatty acids in humans.
This study reports a novel protocol to increase plasma monounsaturated, polyunsaturated, and saturated nonesterified fatty acids (NEFA) in eight healthy volunteers (age 29-54 yr, body mass index 23-26 kg/m(2)). This was achieved by feeding small boluses of fat at different time points (35 g at 0 min and 8 g at 30, 60, 90, 120, 150, 180, and 210 min) in combination with a continuous low-dose heparin infusion. Olive oil, safflower oil, or palm stearin were used to increase monounsaturated, polyunsaturated, or saturated NEFAs, respectively. Plasma NEFA concentrations were increased for 2 h, when fat and heparin were given (olive oil: 745 +/- 35 micromol/l; safflower oil: 609 +/- 37 micromol/l, and palm stearin: 773 +/- 38 micromol/l) compared with the control test (no fat and no heparin: 445 +/- 41 micromol/l). During the heparin infusion, 18:1 n-9 was the most abundant fatty acid for the olive oil test compared with 18:2 n-6 for the safflower oil test and 16:0 for the palm stearin test (P < 0.01). The method described here successfully increases several types of plasma NEFA concentrations and could be used to investigate differential effects of elevated individual NEFAs on metabolic processes.
Beysen
Carine
C
Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Infirmary, United Kingdom.
Belcher
Abigail K
AK
Karpe
Fredrik
F
Fielding
Barbara A
BA
Herrera
Emilio
E
Frayn
Keith N
KN
D000328:Adult; D004041:Dietary Fats / Q000008:administration & dosage*; D005229:Fatty Acids, Monounsaturated / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D006493:Heparin / Q000008:administration & dosage; D006801:Humans; D008066:Lipolysis; D008071:Lipoprotein Lipase / Q000097:blood; D008297:Male; D008875:Middle Aged; D000069463:Olive Oil; D000073878:Palm Oil; D010938:Plant Oils / Q000008:administration & dosage; D012450:Safflower Oil / Q000008:administration & dosage; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D004041:Dietary Fats; D005229:Fatty Acids, Monounsaturated; D005230:Fatty Acids, Nonesterified; D000069463:Olive Oil; D010938:Plant Oils; D014280:Triglycerides; D000073878:Palm Oil; D012450:Safflower Oil; D006493:Heparin; D008071:Lipoprotein Lipase