Cold-induced expression of the metallothionein-1 gene in brown
adipose tissue of rats.
Beattie, John H., Doreen J. Black, Anne M. Wood, and Paul Trayhurn.
Division of Biochemical Sciences, Rowett Research Institute,
Greenburn Road, Bucksburn, Aberdeen AB2 9SB, Scotland, UK
APStracts 2:0285R, 1995.
Heat production by brown adipose tissue (BAT) is important for
thermoregulation in a cold environment. During thermogenesis, oxygen
utilization increases, with an associated rise in free radical
generation. Our objective was to investigate the expression of
metallothionein (MT), which is thought to have an antioxidant role,
in BAT of rats transferred from 25 degrees C to 6 degrees C for 6 or
24 h or maintained at 25 degrees C throughout the study (control
group). For comparison, MT expression was also measured in white
adipose tissue (WAT), liver and kidney. MT-1 mRNA and 18S rRNA were
measured by Northern Blotting using specific digoxigenin labelled
antisense oligonucleotide probes with chemiluminescence detection,
and MT-1 protein was determined by radioimmunoassay. MT-1 mRNA in BAT
increased after 6 h and the mRNA level after 24 h was equivalent to
that in liver, 6 h after injection of rats with 10 mg Zn.kg-1. By 24
h, liver and kidney MT-1 protein had increased, relative to the
controls, by 3- and 1.4-fold, respectively, but in BAT, the relative
induction was 16-fold. Zn injection did not affect BAT MT-1. As with
MT-1 protein, Zn in BAT increased only after 24 h cold exposure. WAT
MT-1 was not affected by any treatment. It is concluded that cold
exposure induces MT-1 in BAT, but in contrast to other tissues
induction may be independent of Zn.
Received 19 June 1995; accepted in final form 18 October 1995.
APS Manuscript Number R370-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 14 November 95