Copper deficiency increases hepatic apolipoprotein b secretion and
mrna editing in rats.
Reaves, Scott K., Ron C. A. J. M. Hoogeveen, Yi Ran Wang, John Y. J.
Wu, and Kai Y. Lei.
Department of Nutritional Sciences, University of Arizona, Tucson,
AZ 85721
APStracts 3:0081C, 1996.
Male weanling Sprague-Dawley rats were assigned to copper-deficient
(9.0 [mu]mol Cu/kg diet) or copper-adequate (102 [mu]mol Cu/kg diet)
dietary treatments, for six weeks. Pulse-chase studies using freshly
isolated rat liver parenchymal cells demonstrated that apoB-48 and
apoB-100 synthesis was not altered but secretion was increased
twofold in hepatocytes derived from copper-deficient rats. Both
plasma apoB-48 and apoB-100 levels appeared to be increased by copper
deficiency but only the apoB-48 increase was found to be significant.
Hepatic apoB mRNA editing, expressed as a ratio of apoB-48 mRNA/apoB
-48 plus apoB-100 mRNA, was significantly increased from 60.8% in
copper-adequate to 70.2% in copper-deficient rats. Moreover, hepatic
apoB mRNA abundance was not significantly altered by copper
-deficiency. Thus, the increased amount of nascent apoB-48 secreted
into the medium as well as the enhanced apoB mRNA editing may have
contributed to the differential increase in plasma apoB-48 over apoB
-100 level in copper-deficient rats.
Received 31 October 1995; accepted in final form 26 February
1996.
APS Manuscript Number C657-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 20 March 96