Effects of estrogen/progestin agents on plasma retinoids and chylomicron remnant metabolism

Gleeson, Jeremy M.; Dukes, Carol S.; Elstad, Nancy L.; Chan, Ing-Fong; Wilson, Dana E.

doi:10.1016/0010-7824(87)90052-7

“…Oestrogens may up-regulate hepatic LDL receptors [28] and result in the rapid clearance of intestinal lipoproteins [29,30], whereas progestin, in contrast with oestrogen, enhances hepatic lipase activity [31]. The present study showed no effect of hormone replacement therapy (oestrogen in the presence or absence of progestin), in agreement with a previous study [32].…”

Section: Discussionsupporting

confidence: 94%

Impaired postprandial clearance of squalene and apolipoprotein B-48 in post-menopausal women with coronary artery disease

Rajaratnam

¹

,

Gylling

²

,

Miettinen

³

1999

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It is not known in detail whether postprandial lipaemia is associated with coronary artery disease (CAD) in women. To investigate this, we administered an oral vitamin A/squalene/fat meal to 24 post-menopausal women with angiographically proven CAD who were not taking hormone replacement therapy, and to 30 healthy controls (18 without and 12 with hormone replacement therapy) to evaluate the effects of CAD on postprandial lipoprotein metabolism. This was done by assessing squalene, triacylglycerols, retinyl palmitate and apolipoprotein B-48 (apoB-48) during the subsequent 24 h. The subjects with CAD had significantly higher fasting concentrations of squalene and apoB-48 in triacylglycerol-rich lipoproteins (TGRL) compared with the controls. The postprandial areas under the incremental curve of TGRL apoB-48, chylomicrons, very-low-density lipoprotein (VLDL) and TGRL squalene, and of retinyl palmitate in VLDL only, were significantly higher in women with CAD than in controls. Adjustment for fasting values did not eliminate the differences in postprandial squalene and apoB-48 between CAD and controls. The postprandial responses of control subjects were not influenced by hormone replacement therapy. The peaks of squalene and retinyl palmitate of the controls, but not of the women with CAD, occurred significantly earlier (P<0.01 for both) in chylomicrons than in VLDL. The findings suggest that lipoproteins that accumulate postprandially are labelled by dietary squalene, and that these lipoproteins may be atherogenic in post-menopausal women.

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“…In addition, postprandial squalene in d 1.006 lipoprotein peaked earlier than retinyl palmitate, and had returned to normal at 24 h, in both groups. The present study showed no effect of hormone replacement therapy (oestrogen in the presence or absence of progestin), in agreement with a previous study [32]. Lipoprotein lipase hydrolyses triacylglycerols of large chylomicrons or VLDL particles, followed by hepatic catabolism of the resulting remnants.…”

Section: Discussionsupporting

confidence: 93%

Impaired postprandial clearance of squalene and apolipoprotein B-48 in post-menopausal women with coronary artery disease

Rajaratnam¹,

Gylling²,

Miettinen³

1999

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It is not known in detail whether postprandial lipaemia is associated with coronary artery disease (CAD) in women. To investigate this, we administered an oral vitamin A/squalene/fat meal to 24 post-menopausal women with angiographically proven CAD who were not taking hormone replacement therapy, and to 30 healthy controls (18 without and 12 with hormone replacement therapy) to evaluate the effects of CAD on postprandial lipoprotein metabolism. This was done by assessing squalene, triacylglycerols, retinyl palmitate and apolipoprotein B-48 (apoB-48) during the subsequent 24 h. The subjects with CAD had significantly higher fasting concentrations of squalene and apoB-48 in triacylglycerol-rich lipoproteins (TGRL) compared with the controls. The postprandial areas under the incremental curve of TGRL apoB-48, chylomicrons, very-low-density lipoprotein (VLDL) and TGRL squalene, and of retinyl palmitate in VLDL only, were significantly higher in women with CAD than in controls. Adjustment for fasting values did not eliminate the differences in postprandial squalene and apoB-48 between CAD and controls. The postprandial responses of control subjects were not influenced by hormone replacement therapy. The peaks of squalene and retinyl palmitate of the controls, but not of the women with CAD, occurred significantly earlier (P<0.01 for both) in chylomicrons than in VLDL. The findings suggest that lipoproteins that accumulate postprandially are labelled by dietary squalene, and that these lipoproteins may be atherogenic in post-menopausal women.

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“…It has been consistently reported that alcohol intake [33,35,43,44] and oral contraceptive use [45][46][47][48] increase vitamin A levels. Actually, in the present study both variables were selected as covariates for vitamin A concentrations in women and, hence, these concentrations were adjusted for such variables prior to the analysis.…”

Section: Resultsmentioning

confidence: 99%

“…It could be estimated that the apoE phenotype explained approximately 3% of the variability of women's vitamin A levels, which was of the same order as that estimated for oral contraceptive use and alcohol intake, two variables whose enhancing effects on vitamin A concentration are well recognized [33,35,[43][44][45][46][47][48]. However, the main predictor of vitamin A levels among the variables studied herein was triglyceride, which explained 18% of its variance, suggesting a link between this vitamin and triglyceride metabolism.…”

Section: Discussionmentioning

confidence: 99%

Influence of apolipoprotein E polymorphism on plasma vitamin A and vitamin E levels

Gómez-Coronado

¹

,

Entrala

²

,

Álvarez

³

et al. 2002

Eur J Clin Investigation

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Effects of estrogen/progestin agents on plasma retinoids and chylomicron remnant metabolism

Cited by 9 publications

References 23 publications

Impaired postprandial clearance of squalene and apolipoprotein B-48 in post-menopausal women with coronary artery disease

Impaired postprandial clearance of squalene and apolipoprotein B-48 in post-menopausal women with coronary artery disease

Impaired postprandial clearance of squalene and apolipoprotein B-48 in post-menopausal women with coronary artery disease

Influence of apolipoprotein E polymorphism on plasma vitamin A and vitamin E levels

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