Degree Type

Dissertation

Date of Award

1981

Degree Name

Doctor of Philosophy

Department

Food and Nutrition

Abstract

The atherosclerotic plaques are characterized by the accumulation of cholesterol and its esters in the peripheral tissues. This stresses the importance of understanding how cholesterol synthesis and utilization are controlled in peripheral tissues in vivo. The usefulness of leucocytes for studying cholesterol synthesis in peripheral tissues has been shown. In the first part of this study the ability of leucocytes to catabolize cholesterol is demonstrated. Presence of cholesterol 7(alpha)-hydroxylase is shown in human leucocytes and peripheral tissues of rat. This suggests that leucocytes can be used for studying both cholesterol synthesis and utilization in peripheral tissues. The second part of the study uses the leucocyte model developed in the first part to study the effects of age and diet composition on cholesterol metabolism in peripheral tissues of men. The plasma leucocytes and lipoproteins of healthy men of three different age groups were analyzed. The results show that the cholesterol levels in the leucocyte, plasma, VLDL AND LDL of the 60-70 yr old men were significantly higher than those of younger groups. The cholesterol synthesis activity in the two older groups was significantly higher than in that of 19-25 yr old men. With increased age plasma and VLDL triglycerides also increased, whereas no significant changes in phospholipid and bile acid levels were seen. Most of the dietary variables had a negative (but not significant) effect on plasma lipids. The results suggest that the diet is not responsible for age associated increase in plasma leucocyte and lipoprotein cholesterol. The increase in plasma cholesterol may reflect a decreased number or function of peripheral cell receptors which are responsible for removal of cholesterol from plasma.

DOI

https://doi.org/10.31274/rtd-180813-6289

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Nina Kanwar Dodd

Language

en

Proquest ID

AAI8209114

File Format

application/pdf

File Size

143 pages

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