Impairment of glucose tolerance: mechanism of action and impact on the cardiovascular system
Article Abstract:
The hormones in birth control pills are thought to alter the metabolism of sugar in the body, as well as to cause high blood pressure, alter lipoproteins, cause weight gain, and increase the risk for coronary heart disease. It is unclear whether all these adverse effects are linked to one common cause. Altered glucose tolerance can be a consequence of either a decrease in insulin secretion or an increased resistance to insulin on the cellular level (decreased insulin action). Since the hormone insulin is essential for glucose metabolism, a decrease in insulin affects the ability of glucose to enter cells. To help understand the relationship between coronary heart disease and impaired glucose tolerance, the factors involved in insulin resistance are examined. In most people, insulin resistance is compensated for by an increase in the secretion of insulin. If the pancreas is incapable of increasing the secretion of insulin, diabetes mellitus results. People who suffer from insulin resistance often suffer from high blood pressure, are obese, have high levels of very low-density lipoproteins and low levels of high-density lipoproteins. All these factors work together in bringing about atherosclerosis and coronary heart disease. This cluster of risk factors, collectively termed syndrome X, is thought to be an inherited defect causing insulin resistance in skeletal muscles. People with syndrome X are thought to have a defect in a key enzyme, glycogen synthetase, decreasing their ability to promote glucose metabolism. The hormones contained in the oral contraceptive pills may produce adverse effects similar to syndrome X, leading to insulin resistance and cardiovascular disease. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1990
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Some aspects of the relationship between oral contraceptives, lipid abnormalities, and cardiovascular disease
Article Abstract:
Altered fat and lipoprotein metabolism has been linked to cardiovascular disease. Cardiovascular disease can occur by an abnormality in the cascade of physiological events that result in clotting. Blood clots can dislodge, travel and block arteries supplying the heart muscle. Cardiovascular disease can also occur when arteries supplying the heart become narrowed and blocked by atherosclerotic plaques. High blood levels of triglycerides and low density lipoproteins (LDL) and low levels of high density lipoproteins (HDL) can combine to increase the risk for cardiovascular disease. It is known that during menopause, when women stop producing estrogen, lipoprotein metabolism changes and their risk of cardiovascular disease goes up. There is some evidence that the hormones in oral contraceptive formulas alter lipoprotein metabolism to increase the risk of cardiovascular disease. The hormone estrogen tends to increase very low density lipoproteins (VLDL) and HDL, while progestins tend to do the opposite. However, pharmacologic estrogen is different than the natural estrogens produced by the body. Evidence is mounting in favor of the theory that oral contraceptives increase the risk of cardiovascular disease by altering the clotting mechanism rather than by causing atherosclerosis. The risk for cardiovascular disease is much lower since the newer low-dose oral contraceptive formulas are given to women having no other cardiovascular risk factors. In women with cardiovascular risk factors, routine lipid profiles should be performed repeatedly. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1990
User Contributions:
Comment about this article or add new information about this topic:
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