Regulation of lipid metabolism in adipose tissue during early
starvation.
Samra, Jaswinder S., Mo L. Clark, Sandy M. Humphreys, Ian A.
Macdonald, and Keith N. Frayn.
Oxford Lipid Metabolism Group, Nuffield Department of Clinical
Medicine, Radcliffe Infirmary, Oxford OX2 6HE, UK, Department of
Physiology and Pharmacology, Medical School, Queen's Medical Centre,
Nottingham NG7 2UH, UK
APStracts 3:0104E, 1996.
We studied changes in lipid metabolism in adipose tissue in 24 healthy
adults during early starvation (14-20 hours) by cannulating the
venous drainage of the subcutaneous adipose tissue of the anterior
abdominal wall. Net non-esterified fatty acid (NEFA) efflux from
adipose tissue increased steadily from 1790 +/- 300 nmol.100g-1.min-1
to 2360 +/- 290 nmol.100g-1.min-1 (P = 0.03), due to increasing
transcapillary efflux of NEFA (release from adipocytes) (P <
0.01). The re-esterification rate after an overnight fast was close
to zero; thus, reduction in the rate of re-esterification 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 behaviour 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.
Received 26 February 1996; accepted in final form 9 May 1996.
APS Manuscript Number E100-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 June 96