[Oral contraceptives and metabolic changes]. / Anticonceptivos orales y alteraciones metabólicas.

PIP: Sufficient evidence has accumulated to relate oral contraceptives (OCs) to various cardiovascular diseases in which metabolic alterations play a role. Although epidemiological studies have shown OC users to be at greater risk of venous thrombosis than nonusers, blood coagulation studies of OC users have yielded conflicting results due to variations in the methodologies used, the factors studied, the different formulations and doses of OCs, and the duration of use. Moreover, no satisfactory method exists of measuring coagulability in its totality, which is the sum of the effects of individual variations in coagulation factors, fibrinolysis, and platelet function. Numerous studies have shown that OC users have increased levels of several coagulation factors, which are believed to indicate hypercoagulability and increased risk of thrombosis, but the pathogenesis of venous thrombosis is complex. Accompanying changes in the fibrinolytic system can be interpreted as attempts to equilibrate the hypercoagulability induced by OCs. Further, there is no proof that in vitro changes are related to thrombosis in vivo. The alterations appear to be dose-related, produced primarily by estrogens, unrelated to duration of use, and to disappear a few months after termination of OC use. OC users have been shown repeatedly to have elevated levels of glucose and insulin, which are especially pronounced in glucose tolerance tests. The changes vary in intensity according to the dose and progestational components and the existence of other risk factors for diabetes. Deterioration of glucose tolerance appears related to duration of OC use, but serum insulin levels maintain the same initial elevations. The estrogens have been shown to have few effects on carbohydrate metabolism in the lower doses currently used. Norgestrel has the most marked effects on glucose and insulin levels, ethynodiol diacetate has moderate effects, and norethindrone has the least effect. The combination of .15 mg levonorgestrel and 30 mcg ethinyl estradiol has no effect on oral glucose tolerance and little effect on insulin secretion. It is hypothesized that OCs affect carbohydrate metabolism by decreasing the number and affinity of insulin receptors in target tissues. The mechanisms by which OCs produce undesirable effects on the cardiovascular system are not completely understood, but are believed to be related to alterations in lipid metabolism. The majority of laboratory studies have shown that OC users had elevated levels of cholesterol, triglycerides, and the (LDL) fractions, and a diminution of the high density lipoprotein (HDL) fraction, which has antiatherogenic properties. The changes are atherogenic in nature and produce a lipid profile similar to that of men and postmenopausal women, who are at greater risk of thrombotic cardiovascular disease that premenopausal women who are protected by estrogens. .^ieng

[Study of various metabolic effects of a contraceptive used for a prolonged period]. / Estudio de algunos efectos metabólicos de un gestágeno usado en forma prolongada.

PIP: The use of oral contraceptive appears to be associated with alterations in glucose tolerance and slight increases of plasma free fatty acids and triglycerides. In this study, the glucose disappearance constant and the plasma levels of nonesterified fatty acids were studied in 63 women, carefully selected with respect to age (20-30 years), parity (less than 4), normal body weight for height and age, absence of obstetric or family precedents suggesting diabetes mellitus, and absence of other pathological conditions. The oral contraceptive (Norlestrin, Parke Davis) was administered during 1 year, starting between the 7th and 9th week of puerperium. Clinical and laboratory tests were performed before the administration of the drug, and after 3, 6, and 12 months. The number of patients was reduced to 36 at the 1st control, 30 at the 2nd, and 24 at the 3rd. A progressive deterioration of the glucose disappearance constant was observed, with significant differences (p less than .001) between the values before and 12 months after treatment. Diabetic-level values were absent. The plasma nonesterified fatty acids showed a progressive and significant increase, interrupted only during the glucose tolerance tests. There was an average increase in body weight of 4 kg at the 1st control, followed by normalization at the 12th month of treatment. The study discusses the possible causes of such alterations, emphasizing the role of many functi ons that maintain metabolic homeostasis.^ieng

[Changes in carbohydrate metabolism during the administration of progestational hormones]. / Modificaciones del metabolismo de los hidratos de carbono durante la administración de progestágenos.

PIP: Changes in the levels of plasma glucose and serum insulin and growth hormone after oral and iv administration of glucose and infusion of arginine in a group of 35 carefully selected normal women were studied. The tests were performed before and during the administration of progestins of the sequential and combination type (Oracon and Ovulen, respectively), during the 2nd or 3rd cycle of treatment. The results showed that both types of treatment produced a significant increase in the serum insulin and growth hormone levels, while the plasma glucose level remained unaltered in the various tests. It would appear that these drugs produce an increase in peripheral resistance to insulin, since the insulin-glucose index rose in the growth hormone level, may also be due to an antiinsulin action and/or to changes in the production of insulin directly caused by the drugs.^ieng