Regulation of lipid metabolism in adipose tissue during early starvation.
We studied changes in lipid metabolism in adipose tissue in 24 healthy adults during early starvation (14-20 h) by cannulating the venous drainage of the subcutaneous adipose tissue of the anterior abdominal wall. Net nonesterified fatty acid (NEFA) efflux from adipose tissue increased steadily from 1,790 +/- 300 to 2,360 +/- 290 nmol.100 g-1.min-1 (P = 0.03), due to increasing transcapillary efflux of NEFA (release from adipocytes; P < 0.01). The reesterification rate after an overnight fast was close to zero; thus, reduction in the rate of reesterification played no part in the increased transcapillary efflux of NEFA. One-quarter of the net efflux of NEFA after an overnight fast arose from the action of lipoprotein lipase (LPL), although this relative contribution decreased during the study (P < 0.02). The increased transcapillary efflux of NEFA reflected a significant increase in the rate of action of hormone-sensitive lipase (HSL; P = 0.03). There was a strong relationship between mean arterial NEFA concentration and net NEFA release from adipose tissue (P < 0.001), implying that the particular depot studied reflects the behavior of adipose tissue as a whole. Thus the increasing efflux of NEFA from adipose tissue observed during early starvation is due to an increased rate of action of HSL, which may in turn be regulated by a fall in the plasma insulin concentration.
Samra
J S
JS
Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford, United Kingdom.
Clark
M L
ML
Humphreys
S M
SM
Macdonald
I A
IA
Frayn
K N
KN
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D013217:Starvation
D005227:Fatty Acids; D008071:Lipoprotein Lipase