Sukenari Sasagawa

SESAME LIGNANS MODULATE CHOLESTEROL METABOLISM IN THE STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RAT

1. Effects of sesamin and episesamin (an epimer of sesamin) on lipid metabolism, in particular cholesterol metabolism, were examined in normocholesterolaemic and hypercholestero‐laemic stroke‐prone spontaneously hypertensive rats (SHRSP).

Effect of Cholesterol Feeding on the Compositions of Plasma Lipoproteins and Plasma Lipolytic Activities in Shrsp

By cholesterol feeding, atherogenic VLDL, beta-VLDL (IDL) and LDL increased more remarkably in SHRSP than in normotensive WKY, suggesting that hypertension may promote the productions of atherogenic lipoproteins. On the other hand, HDL significantly decreased in SHRSP, which was associated with the decrease in apoA-I and E in the HDL fraction. This indicates the decreases of two HDL subfractions, apoE HDL and apoA-I HDL, in SHRSP. These decreases of HDL subfractions in SHRSP may be closely related to the higher h-TGL activity in SHRSP than in WKY, and could be a trigger of the excess production of atherogenic lipoproteins.

Clonal lifespans cultured in chemically defined medium and conventional bacterized medium in Paramecium octoaurelia

The unicellular ciliate, paramecium, reproduces by binary fission, but can not continue to divide unlimitedly without sexual reproduction. We examined the clonal life span of Paramecium octaurelia stock 299 cultured in conventional bacterized medium (BM) and a chemically defined medium (DM). The cells that lived in BM divided 300 times. Although the cells in DM divided more slowly, some cells continued to divide more than 100 times. The mean life span of 90 cell lines cultured in BM was 151 +/- 49 fissions and that of 84 cell lines in DM was 68 +/- 28. When some older cells, which had been cultured in DM, were transferred to BM, most of them showed much longer life spans than those remaining in DM. The results showed that the life spans of cell clones were affected by the culture conditions.

Studies on Stroke-Prone Spontaneously Hypertensive Rats (SHRSP) Fed a High-Fat and High-Cholesterol Diet

Studies on serum lipo- and apo-proteins have rapidly progressed in recent years since epidemiologic studies demonstrated that there is a negative correlation between the concentration of high density lipoprotein-cholesterol (HDL-cholesterol) and the occurrence of coronary heart disease, and that HDL, especially HDL2, is an anti-atherogenic factor.On one hand, the stroke-prone spontaneously hypertensive rat (SHRSP) which was established in 1974, develops arterial fat deposition by high-fat and -cholesterol (HFC) feeding, and is suggested as a useful model for studies on atherosclerosis.In this report, we investigated 1) serum lipo- and apo-proteins in male SHRSP in comparison with those in age-matched male Kyo: Wistar rat (WKY), and 2) alterations of serum lipo- and apo-proteins in both strains by HFC feeding. In particular, alterations of HDL subfractions were examined by Heparin-Sepharose 4B affinity chromatography.First, various lipoproteins were fractionated from rat serum by density gradient ultracentrifugation, followed by characterization with various polyacrylamide gel electrophoreses. Next, HDL fraction was subfractionated into two distinct subclasses, HDL rich in apoprotein A-I (Apo A-I HDL) and HDL rich in apoprotein E (Apo E HDL), by Heparin-Sepharose 4B affinity chromatography.We noticed that the content of Apo E HDL including HDL1 in SHRSP was much lower than that in WKY, which was associated with lower content of Apo E in low density lipoprotein- (LDL-) and HDL-fractions of SHRSP. But, it remains to be determined whether the decreased content of Apo E HDL in SHRSP is due to genetic factors or the secondary effects of hypertension.In WKY on HFC diet, there was a decrease of Apo E HDL associated with a decrease of Apo E in HDL fraction and an increase of both Apo E and Apo B in LDL- and very low density lipoprotein-(VLDL-) fractions. In SHRSP on HFC diet, the changes were more drastic than those in WKY. Not only Apo E HDL but also Apo A-I HDL decreased, wchich was associated with a decrease of both Apo E and Apo A-I in HDL fraction and a small increase of Apo E and large increase of Apo B in LDL- and VLDL-fractions. These remarkable changes of lipo- and apo-proteins in SHRSP resulted in the decrease of total HDL and the rapid elevation of serum total cholesterol, which could induce the development of arterial fat deposition.