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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of short-term (6 months) administration of conjugated equine estrogen (Premarin) on content and composition of the aortic sterols in male shite Carneau pigeons while they were on a cholesterol-free grain diet was investigated. Estrogen treatment resulted in a 38% increase (P less than 0.05) in free sterol concentration, with a 28.8% concomitant decrease (P less than 0.05) in the percent of cholesteryl esters. The total sterol concentration remained unchanged. This finding suggests that estrogens might influence the synthetic or hydrolytic (or both) processes that control the concentration of cholesteryl esters in the aorta. Fatty acid composition of steryl esters did not change significantly. The cholesterol content of plasma showed a mild reduction (14%) whereas the triglycerides increased significantly (30%).
Atherosclerosis 1977 May
PMID:Effect of estrogens on the concentration and composition of arterial sterols and steryl esters in male white carneau pigeons. 19 27

The effect of cholesterol feeding and estrogen administration on synthesis of fatty acids in liver mitochondria, microsomes and cytoplasm of male rabbits has been investigated. The synthesis was measured by the incorporation of [1(-14)C] acetyl CoA or [2(-14)C]malonyl CoA into long chain fatty acids under optimal conditions. It was found that atherogenesis markedly decreased the fatty acid synthesis in cytoplasm. The mitochondrial fatty acid synthesis was not affected by the disease. There was a small but measurable decrease in the synthesis of fatty acids in microsomes. Estrogen had no effect on the synthesis of fatty acids in mitochondria or microsomes. But if effectively counteracted, after a short lag period, the decreased synthesis of cytoplasmic fatty acids observed in atherosclerosis. It is possible that liver fatty acid synthetase is one of the enzyme systems through which estrogens exert their atherosclerosis-retarding effect. The decreased cytoplasmic fatty acid synthesis observed in atherosclerosis might account for the low levels of saturated fatty acids reported in liver and plasma lipids of atherosclerotic animals.
Atherosclerosis 1977 Aug
PMID:Effect of cholesterol feeding and estrogen treatment on synthesis of fatty acids in liver. 88 99

Lipoprotein lipase (LPL) activity was measured in adipose tissue, heart and diaphragm in Sprague--Dawley rats after estrogen therapy or orchiectomy. Enzyme activity was measured by incubation of tissue fragments with a triolein emulsion in the presence of serum and heparin. In confirmation of other work, depression of adipose tissue LPL followed estradiol treatment in pharmacologic or near-physiologic doses. Cardiac and diaphragmatic muscle LPL were increased. Estrogen-treated male animals showed growth retardation. However, they gained weight steadily and did not show significant differences in serum insulin, glucose of D-beta-hydroxybutyrate. The effects of estradiol in male animals were reversed by sequential fasting and re-feeding. At times during growth and aging in normal female rats, adipose tissue activity was decreased while cardiac and skeletal muscle activities were increased relative to males of the same age or body weight. Castration of male rats failed to reproduce the effect of estrogens on tissue lipoprotein lipase. These in vitro data suggest that exogenous estrogens may shift the flux of triglyceride fatty acids from storage in the adipose organ toward incorporation by muscle. These, and other data, raise the possibility that physiological estrogen secretion exerts a tonic influence over the synthesis and ultimate destination of triglyceride fatty acids.
Atherosclerosis 1976 Sep
PMID:Estrogen treatment and gonadal function in the regulation of lipoprotein lipase. 97 48

Estrogen replacement therapy may offer significant benefits to nearly all postmenopausal women, especially those for whom the menopause occurred at an early age. Women at high risk for atherosclerosis, or who already have cardiovascular disease, may particularly benefit from estrogen use. The increased risk for endometrial and breast cancer seen with estrogen replacement therapy is low in comparison with its protective effect against cardiovascular disease. For women who cannot or choose not to take estrogens, etidronate may be of value in preventing osteoporotic fractures. For women many years beyond menopause who consume low-calcium diets, calcium supplementation should be recommended.
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PMID:Menopause: advanced management strategies. 181 2

The metabolic effects of sex steroids pertinent to cardiovascular risk are described. These effects are discussed for estrogen inducible proteins, coagulation and fibrinolysis, blood pressure and hypertension, carbohydrate metabolism, lipids and lipoproteins, and vessel walls and local prostaglandins. Also described is the cardioprotection from estrogens and estrogen/progesterone treatment and cardiovascular risk. Oral contraceptive (OC) and cardiovascular risk are also discussed with the following effects identified: the influence on many of the multiple risk factors involved in the development of cardiovascular diseases (i.e., lipids, carbohydrate metabolism, and hemostasis), an association between OC use and thromboembolic accidents, a state of hypercoagulability counterbalanced by increased fibrinolytic activity, venous thrombosis, a relationship with the dosage of androgenic progestogens. no atherogenic origin, no age limit for prescribed, healthy, nonsmoking women, and an increased peripheral insulin resistance. It is concluded that it is rarely inadvisable to prescribe low dose natural estrogens in postmenopausal hormone replacement therapy. Factors contraindicating such use are undiagnosed genital bleeding, an active thrombolic or cardiovascular process, carcinoma of the breast or endometrium, and acute liver failure. Estrogen replacement therapy may exert some cardioprotective effect. When progestogens are added to prevent endometrial carcinoma development, the benefits might be reduced. Low estrogen and low progesterone OC use among healthy, nonsmoking women even in middle age poses no risk of death from cardiovascular disease. Premenopausal women may even be protected from coronary atherosclerosis with estrogen-containing OCs. However, it is advisable that OCs be used with the least possible impact on lipid and carbohydrate metabolism, as well as on hemostasis. For those with some prior cardiovascular risk, there are theoretical advantages at present for use of the new, less, or nonandrogenic progestins in OCs; however, caution is urged and informed consent must be obtained until epidemiological studies support this position.
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PMID:Sex hormones and cardiovascular risk. 192 64

The combined progestogen/estrogen oral contraceptive is the most common form of contraception in the US. They contain 1 of 5 synthetic progestogens (derived from 19-nortestosterone) and 1 of 2 estrogens. 3 new progestin compounds are in use in Europe and Asia. They are norgestimate, desogestrel, and gestodene. Estrogen seems to cause vascular complications. Progestin may cause atherosclerosis. Desogestrel and gestodene were studied for 6 months. They have little effect on glucose and lipid metabolism. Triphasal ethinyl estradiol/levonorgestrel and ethinyl estradiol/norethindrone (Ortho Novum 7/7/7) were compared in a 12-month prospective clinical trial. There seems to be no consensus of a pattern of increased breast cancer associated with oral contraceptive use. The UK National Case Control Study Group analyzed women younger than 36 years at the time breast cancer was diagnosed. 91% of their cohort had used pills. A significant trend was found when risk was analyzed with duration of taking pills. Women who had taken the pill for 4 years had no increased risk of breast cancer. However, there was an increased relative risk of 1.7 (P0.001) for women who took pills for more than 8 years. Among women using the pill for 8 years, the relative risk was 2.6 (p0.0001). AMong women using pills with 50 ug. of estrogen, the trend to increased risk was (P0.10). The 1988 National Survey of adolescent males showed that 60% of men never married were active sexually. Among 17- to 19-year-old-men who live in metropolitan areas, condom use has more than doubled, compared with 1979. In 1988, a "new" copper-containing IUD was approved for use in the US by the Food and Drug Administration, the Copper T 380 A. Pregnancy rates are less with this than with older devices. IUDs may cause pelvic inflammatory disease with resulting tubal infertility. However, the risk was overstated earlier. Women who have only 1 sexual partner in their lifetime had no significant risk of tubal infertility. "lost" IUDs continue to be a problem.
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PMID:Contraception. 210 26

In 17 prostatic cancer patients, changes in the plasma lipoprotein pattern, including high density lipoprotein (HDL) subfractions, and in glucose tolerance were compared after 6 months on parenteral polyestradiol phosphate (PEP; Estradurin, 80 or 160 mg/month) with the respective changes in orchiectomized patients. In the estrogen group there was no change in the total serum cholesterol level, whereas in the orchiectomy group an increase of 10% was observed. Estrogen therapy resulted in a significant increase of serum HDL (11%) and HDL2 cholesterol (26%) levels; in the orchiectomy group these fractions remained unchanged. Estrogen therapy induced a significant decrease in total serum triglycerides (24%) and in low density lipoprotein triglycerides (27%); in the orchiectomy group reverse changes were observed. PEP treatment caused changes in the serum lipoprotein pattern, which apparently decreases the risk of atherosclerosis.
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PMID:Effects of orchiectomy and polyestradiol phosphate therapy on serum lipoprotein lipids and glucose tolerance in prostatic cancer patients. 235 Nov 92

The inhibition of atherosclerosis by estrogen has been shown clinically and experimentally, but the mechanism by which this occurs is unknown. Previous studies have shown that estrogen enhances the uptake of low-density lipoprotein (LDL) by bovine aortic endothelial cells (BAEC) while not altering membrane binding at saturating levels of LDL. In this study the effect of estrogen on LDL binding kinetics has been investigated. Computer-assisted Scatchard analysis of binding data suggests a single-site binding model. Estrogen-treated BAEC showed a lower binding affinity (Ka = 2.47 +/- 0.74 E7 M-1) than control cells (1.95 +/- 0.21 E7 M-1) (p = 0.0012). Estrogen-treated cells, however, had a greater binding capacity (Bmax = 1.26 +/- 0.07 E-10M) than control cells (Bmax = 8.49 +/- 0.44 E-11M) (p = 0.0004). The latter was due primarily to a difference in LDL binding at higher concentrations of LDL (greater than 40 micrograms/ml). These findings are consistent with an estrogen-stimulated increase in low-affinity binding of LDL to BAEC, which may not be directly receptor mediated and which appears to enhance the uptake of LDL at higher lipoprotein concentrations. Such alterations in LDL uptake by endothelial cells could influence the formation of atherosclerotic plaque.
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PMID:The effect of estrogen on low-density lipoprotein binding kinetics in aortic endothelial cells. 254 95

The means by which estrogen retards atherosclerosis cannot be explained solely by changes in circulating lipoprotein levels. We studied the effects of 17 beta-estradiol on the binding, incorporation, and degradation of low density lipoprotein (LDL) by cultured bovine aortic endothelial cells (BAEC). Estrogen receptors in the cytoplasm and nucleus of BAEC could be demonstrated by immunofluorescent staining. Estradiol was found not to affect surface binding of LDL to BAEC. However, at physiologic concentrations (50 pg/ml), estradiol did enhance LDL uptake by the BAEC (P less than 0.005). This enhancement was present but somewhat reduced at higher concentrations of estrogen (P less than 0.05). Only approximately 10% of incorporated LDL was trichloroacetic acid soluble, indicating a low rate of LDL degradation. The relative rate of LDL breakdown within the BAEC was not altered by estrogen. These results, showing estrogen stimulation of LDL uptake by the BAEC, do not clarify the protective effect of this hormone. It is speculated that estrogen may augment the cellular clearance of LDL.
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PMID:Effect of estradiol on low density lipoprotein uptake by bovine aortic endothelial cells. 265 94

It has been well documented that low-density lipoproteins and intermediate-density lipoproteins play a role in the development of atherosclerosis. Data also indicate that high-density lipoproteins (HDLs), have potentially antiatherogenic effects. The individual estrogen and progestogen components of oral contraceptives (OCs) have been shown to affect plasma lipoproteins in both cross-sectional and longitudinal studies. This effect depends on both the type of steroid used and the dose of each of the OC components. Estrogen and progestogen have opposing effects on lipoprotein physiology. Estrogens raise the level of HDL cholesterol, while progestogens tend to lower HDL levels. Thus, in OC formulations, as the ratio of estrogen to progestogen increases in favor of estrogen, there is a greater increase in HDL cholesterol--a potentially beneficial effect. Although there is no direct evidence that favorable lipoprotein changes produced by OCs are cardioprotective, the physician prescribing an OC should minimize adverse lipoprotein effects by prescribing a balanced low-dose, low-impact formulation.
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PMID:The effects of oral contraceptives on plasma lipids and lipoproteins. 290 39


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