Article

The Journal of Membrane Biology

, Volume 131, Issue 1, pp 35-42

First online:

The calcium uptake of the rat heart sarcoplasmic reticulum is altered by dietary lipid

  • George E. TaffetAffiliated withSections of Cardiovascular Sciences, Geriatric Medicine and Atherosclerosis Research, Department of Medicine, Baylor College of Medicine, and The Methodist Hospital
  • , Thuy Thu PhamAffiliated withSections of Cardiovascular Sciences, Geriatric Medicine and Atherosclerosis Research, Department of Medicine, Baylor College of Medicine, and The Methodist Hospital
  • , Diane L. M. BickAffiliated withSections of Cardiovascular Sciences, Geriatric Medicine and Atherosclerosis Research, Department of Medicine, Baylor College of Medicine, and The Methodist Hospital
  • , Mark L. EntmanAffiliated withSections of Cardiovascular Sciences, Geriatric Medicine and Atherosclerosis Research, Department of Medicine, Baylor College of Medicine, and The Methodist Hospital
  • , Henry J. PownallAffiliated withSections of Cardiovascular Sciences, Geriatric Medicine and Atherosclerosis Research, Department of Medicine, Baylor College of Medicine, and The Methodist Hospital
  • , Roger J. BickAffiliated withSections of Cardiovascular Sciences, Geriatric Medicine and Atherosclerosis Research, Department of Medicine, Baylor College of Medicine, and The Methodist Hospital

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Summary

Small amounts of dietary n-3 fatty acids can have dramatic physiological effects, including the reduction of plasma triglycerides and an elevation of cellular eicosapentanoic (EPA) and docosahexanoic acids (DHA) at the expense of arachidonic acid (AA). We investigated the effects of alterations in the fatty acid compositions of cardiac sarcoplasmic reticulum (CSR) produced by dietary manipulation on the calcium pump protein that is required for energy dependent calcium transport. CSR was isolated from rats fed menhaden oil, which is rich in n-3 fatty acids, and from control animals that were given corn oil. Relative to control membranes, those isolated from rats fed menhaden oil, had a lower content of saturated phospholipids, an increased DHA/AA ratio, and an increased ratio of n-3 to n-6 fatty acids. These changes were associated with a 30% decrease in oxalate-facilitated, ATP-dependent calcium uptake and concomitant decreased Ca-ATPase activity in the membranes from the animals fed menhaden oil. In contrast, there was no alteration in active pump sites as measured by phosphoenzyme formation. Thus, the CSR Ca-ATPase function can be altered by dietary interventions that change the composition, and possibly structure, of the phospholipid membranes thereby affecting enzyme turnover.

Key words

sarcoplasmic reticulum diet fatty acids phospholipids calcium adenosine triphosphatase turnover