Alterations in myocardial lipid metabolism during lactation in the rat. Wang, Xin, David G. Hole, Teresa H. M. Da Costa, Rhys D. Evans. Nuffield Department of Anaesthetics, University of Oxford, Radcliffe Infirmary, Woodstock Road, OXFORD, Oxfordshire OX2 6HE U.K., Metabolic Research Laboratory, Nuffield Department of Clinical Medicine, University of Oxford, Radcliffe Infirmary, Woodstock Road, OXFORD, Oxfordshire OX2 6HE U.K., Universidade de Brasilia, Departamento de Nutri__o, Campus Universit[beta]rio - Asa Norte, CEP 70919-970, BRASILIA-DF, Brazil
APStracts 5:0106E, 1998.
Metabolism of non-esterified fatty acid (palmitate, 1.1mM) and triacylglycerol (TAG; triolein, 0.4mM in the form of both rat chylomicrons and very-low density lipoproteins) was studied in isolated perfused working hearts from fed nulliparous, lactating and weaned rats. Hearts from virgin rats oxidised palmitate readily but optimal cardiac mechanical performance occurred during perfusion with chylomicrons. In hearts from lactating dams, there was a significant increase in palmitate oxidation, and a marked decrease in TAG oxidation from both chylomicrons and VLDL compared to hearts from nulliparous animals. There was a concomitant decrease in lipoprotein lipase activity in hearts from lactating animals and TAG in the absence of palmitate could not support optimal cardiac mechanical function. Following litter removal, the changes in fatty acid and triacylglycerol metabolism observed in lactation returned to nulliparous values within 96h. These results suggest that during lactation both exogenous and endogenous triacylglycerols are directed away from heart, and towards the lactating mammary gland; the heart therefore has to rely to a greater extent on non-esterified fatty acid for energy provision under these conditions. 

Received 13 January 1998; accepted in final form 29 April 1998.
APS Manuscript Number E6-8.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 8 May 1998