The effect of estrogens on carbohydrate metabolism: glucose, insulin, and growth hormone studies on one hundred and seventy-one women ingesting Premarin, mestranol, and ethinyl estradiol for six months

The Prevalence and Associated Risk Factors of Impaired Glucose Regulation in Chinese Adults: A Population-Based Cross-Sectional Study

The goal of this study was to determine the prevalence and associated risk factors of impaired glucose regulation (IGR) in the population of Tongzhou, China, and to provide scientific basis for preventive interventions. In the study, the overall age-standardized prevalence of IGR (16.0%) in Tongzhou residents was higher than that in the national population (15.0%). There was no significant geographic difference in prevalence of IGR between urban and rural males. Older age, elevated blood pressure, high serum lipids, overweight, and central obesity were significantly associated with increased risk of IGR.

Effect of oral estrogen on substrate utilization in postmenopausal women

We tested the hypothesis that a 2-month intervention with unopposed oral conjugated equine estrogens (0.625 mg/d) would decrease lipid oxidation, as assessed by 24-hour, whole-room, indirect calorimetry in 14 postmenopausal women. Estrogen (E) treatment was associated with declines in both 24-hour and postprandial lipid oxidation and an increase in fat mass (mean [+/-SD] 2-month difference 1.1 +/- 1.0 kg; mean 6-month difference 1.8 +/- 2.2 kg), suggesting that, on an acute basis, oral E may increase adiposity by limiting lipid oxidation.

Effect of oestrogen plus progestin on the incidence of diabetes in postmenopausal women: results from the Women's Health Initiative Hormone Trial

AIMS/HYPOTHESIS

Studies examining the effect of postmenopausal hormone therapy on concentrations of glucose, insulin and diabetes incidence have been inconclusive, in part because many of the studies were too small. We examined the effect of oestrogen plus progestin on diabetes incidence and insulin resistance.

METHODS

The study was a randomised, double-blind trial comparing the effect of daily 0.625 mg conjugated equine oestrogens plus 2.5 mg medroxyprogesterone acetate with that of placebo during 5.6 years of follow-up. The participants were 15,641 postmenopausal women enrolled in the Women's Health Initiative Hormone Trial. These women were aged 50 to 79 and all had an intact uterus. Diabetes incidence was ascertained by self-report of treatment with insulin or oral hypoglycaemic medication. Fasting glucose, insulin, and lipoproteins were measured in a random sample at baseline and at 1 and 3 years.

RESULTS

The cumulative incidence of treated diabetes was 3.5% in the hormone therapy group and 4.2% in the placebo group (hazard ratio 0.79, 95% CI 0.67-0.93, p=0.004). There was little change in the hazard ratio after adjustment for changes in BMI and waist circumference. During the first year of follow-up, changes in fasting glucose and insulin indicated a significant fall in insulin resistance in actively treated women compared to the control subjects (Year 1 to baseline between-group difference -0.22+/-0.10, p=0.03). INTERPRETATIONS/CONCLUSION: These data suggest that combined therapy with oestrogen and progestin reduces the incidence of diabetes, possibly mediated by a decrease in insulin resistance unrelated to body size. Future studies of alternative postmenopausal hormone therapy regimens and selective oestrogen agonists and/or antagonists should consider the effects of these regimens on insulin resistance and diabetes.

Androgenicity and obesity are independently associated with insulin sensitivity in postmenopausal women

An increase in androgenicity may contribute to the development of insulin resistance in postmenopausal women. Increased androgenicity in women has been found to be associated with the development of type 2 diabetes. In addition, obesity and central obesity are associated with greater androgenicity. Insulin sensitivity, androgenicity, and body composition were characterized in 34 nondiabetic postmenopausal women age 72 +/- 1 years (mean +/- SEM) to test the hypothesis that androgenicity is a predictor of insulin sensitivity independent of measures of obesity. Androgenicity was measured using levels of sex hormone-binding globulin (SHBG), total and free testosterone, dehydroepiandrosterone sulfate (DHEA-S), androstenedione, and free androgen index (FAI). Insulin sensitivity (S(I)) was determined from a frequently sampled intravenous glucose tolerance test. Body composition measures included body mass index (BMI) and dual energy x-ray absorptiometry measurements of total and central fat mass. S(I) was found to be associated with total fat mass (r = -.51, P =.002), central fat mass (r = -.62, P =.0001), BMI (r = -.55, P =.0008), SHBG levels (r =.65, P =.0001), and FAI (r = -.41, P =.01). SHBG levels were inversely correlated with central fat mass (r = -.59, P =.0002). Using multiple regression, SHBG and central fat mass were the only significant independent predictors of S(I), accounting for 50% of its variance (r =.71, P =.0001); total fat mass, BMI, total and free testosterone, DHEA-S, androstenedione, and FAI did not enter the model. We conclude that there is a significant association between insulin sensitivity and androgenicity in postmenopausal women that is independent of obesity. Interventions to decrease androgenicity may therefore be useful in improving insulin sensitivity in postmenopausal women.

Differential effects of raloxifene and estrogen on insulin sensitivity in postmenopausal women

OBJECTIVES

To test the hypothesis that both raloxifene and estrogen would improve insulin sensitivity in postmenopausal women and that the magnitude of the effect would be similar for both drugs.

DESIGN

Placebo-controlled, double-blind, randomized study.

SETTING

The General Clinical Research Center of the University of Michigan Medical Center, a university hospital.

PARTICIPANTS

Forty-four healthy postmenopausal women 73 +/- 7 years old (mean age +/- standard deviation) who were not receiving hormone replacement therapy.

INTERVENTION

Eight weeks of drug therapy with randomization to raloxifene (n = 16), estrogen (n = 14), or placebo (n = 14).

MEASUREMENTS

These subjects underwent a frequently sampled intravenous glucose tolerance test to determine insulin sensitivity (SI) and total and regional (central) body composition measurements by dual-energy x-ray absorptiometry at baseline and after 8 weeks of drug therapy.

RESULTS

There were no statistically significant differences in age, body mass index, total or central fat mass, or SI between the three groups at baseline. The major outcome variable was SI. After 8 weeks of drug therapy, there was no significant change in SI in the placebo group or in the estrogen group and a significant decrease in SI in the raloxifene group, P =.003.

CONCLUSION

In contrast to estrogen's ability to maintain insulin sensitivity, raloxifene decreases insulin sensitivity in healthy nondiabetic postmenopausal women. The clinical significance of this effect of raloxifene to impair insulin sensitivity in postmenopausal women warrants further evaluation in future studies.

HRT does not improve urinary albumin excretion in postmenopausal diabetic women

The effect of 6 months combined, continuous hormone replacement therapy (HRT) with conjugated equine oestrogen (0.625 mg) and medroxyprogesterone acetate (2.5 mg) on albumin/creatinine ratio (ACR) was determined in postmenopausal diabetic women in a randomised, controlled study. Mean (interquartile range) change in plasma ACR was not (P=0.96) different in women receiving HRT [2 (-11, 21) mg/g, n=20] compared with those randomised to placebo [2 (-1, 14) mg/g, n=27]. Also, the proportion of women with microalbuminuria did not change (P=0.75) during HRT (baseline, 0.45; end of study, 0.53). Furthermore, several risk factors for microalbuminuria including systolic blood pressure (SBP), fasting blood glucose, glycated haemoglobin (HbA1c) and adiposity did not vary significantly during HRT. These data suggest that 6 months HRT does not reverse microalbuminuria caused by prolonged hyperglycaemia and other risk factors that underlie leakage of albumin into the urine in postmenopausal women with type 2 diabetes.

Effects of oral contraceptives on glucose flux and substrate oxidation rates during rest and exercise

We examined the effects of oral contraceptives (OC) on glucose flux and whole body substrate oxidation rates during rest (90 min) and two exercise intensities [60-min leg ergometer cycling at 45 and 65% peak O(2) uptake (Vo(2 peak))]. Eight healthy, eumenorrheic women were studied during the follicular and luteal phases before OC and the inactive and high-dose phases after 4 mo of a low-dose, triphasic OC. Subjects were studied in the morning 3 h after a standardized (308 kcal) breakfast. There were significant reductions in glucose rates of appearance and disappearance during exercise of both intensities with OC but not rest. There were no phase effects on substrate oxidation during rest or exercise. These results are interpreted to mean that, in women fed several hours before study, 1) OC decreases glucose flux, but not overall carbohydrate and lipid oxidation rates during moderate-intensity exercise; and 2) synthetic ovarian hormone analogs in the doses contained in OC have greater metabolic effects on glucose metabolism during exercise than do endogenous ovarian hormones.

The use of hormone replacement therapy in postmenopausal women with type 2 diabetes

In healthy postmenopausal women, estrogen or hormone replacement therapy (ERT or HRT) can alleviate menopausal symptoms and prevent osteoporosis and may also protect against cardiovascular disease (CVD). In addition to improving lipid metabolism, there are reports that estrogen also improves parameters regulating carbohydrate metabolism, including insulin resistance, in healthy women. Therefore, it is likely that ERT or HRT would also benefit women with type 2 diabetes, not only in relieving menopausal symptoms but also in improving the metabolic abnormalities associated with diabetes and in preventing cardiovascular disease.

The effects of sequential combined oral 17beta-estradiol norethisterone acetate on insulin sensitivity and body composition in healthy postmenopausal women: a randomized single blind placebo-controlled study

OBJECTIVE

The androgenic effect of progestogen, necessary in early postmenopausal hormone replacement therapy (HRT), may adversely affect insulin sensitivity as well as body fat distribution and thereby increase the cardiovascular risk profile. The impact of HRT with sequential combined oral 17beta-estradiol and norethisterone acetate on insulin sensitivity and body composition in early menopause has not been studied.

DESIGN

A randomized single blind placebo-controlled 6-month study of sequential combined 17beta-estradiol norethisterone acetate on insulin sensitivity and body composition was carried out. Thirty fit healthy postmenopausal women were enrolled and completed this 6-month study. Body composition was measured by dual-energy x-ray absorptiometry scanning, and insulin sensitivity was measured using the euglycemic hyperinsulinemic clamp. Studies were undertaken at baseline and after 6 months of therapy. The studies were performed during the estrogen-only phase of therapy.

RESULTS

All women demonstrated a degree of decreased insulin sensitivity that was not modified by 6 months of hormone replacement therapy. Body composition remained unchanged over 6 months. There was no alteration in total body fat or the distribution of body fat. The percentage of central abdominal fat (android) was not altered.

CONCLUSION

Six months of HRT with sequential combined oral 17beta-estradiol norethisterone acetate does not have an adverse effect on insulin sensitivity and does not promote an increase in weight or the more android distribution of body fat, which could contribute to the increased cardiovascular risk profile that is evident in postmenopausal women.

Various actions of oestrogens on the vascular system

Epidemiological studies show a reduction in cardiovascular disease with postmenopausal oestrogen use. Oestrogens have been shown to have both metabolic effects and direct effects on the vasculature, both of which may improve arterial function and reduce or reverse atheroma formation. The metabolic effects include changes in lipids and lipoproteins, glucose and insulin metabolism, coagulation and fibrinolysis. The direct arterial effects include changes in endothelium-dependent processes, ion channels, renin-angiotensin system and remodelling processes. The various actions of oestrogens on the vascular system are reviewed. It is clearly important to understand the biological basis of these effects of oestrogen on the cardiovascular system in order to optimize current and future hormone-replacement therapy in women after natural or surgical menopause.

A randomized cross-over study comparing pharmacodynamic and metabolic variables of a new combiphasic and a well-established triphasic oral contraceptive

In an open-label, randomized, cross-over study in 20 subjects, the short-term effects were investigated of Gracial (DSG/EE 7 x 25/40 micrograms/day + 15 x 125/30 micrograms/day) and Trigynon (LNG/EE 6 x 50/30 micrograms/day + 5 x 75/40 micrograms/day + 10 x 125/30 micrograms/day) on plasma concentrations of 17 beta-estradiol and progesterone as well as on carrier proteins (SHBG, CBG, ceruloplasmin), AT-III, carbohydrate metabolism (insulin, glucose, glycosylated proteins) and lipid metabolism (total cholesterol, triglycerides, phospholipids, HDL-C, LDL-C, HDL2-C, HDL3-C, HDL2-C/HDL3-C ratio, Apo A1, Apo B, Apo A1/Apo B ratio). Both preparations adequately and similarly inhibited ovulation in all subjects. Serum levels of carrier proteins were significantly higher with DSG/EE than with LNG/EE, whereas no between-group differences were observed with respect to fasting glucose and insulin, glycosylated proteins (mainly glycosylated albumin) and AT-III activity. DSG/EE showed significantly higher plasma levels than LNG/EE of estrogen-dependent lipid parameters such as triglycerides, HDL-C, HDL2-C, Apo A1, HDL2-C/HDL3-C ratio and Apo A1/Apo B ratio, whereas the levels of LDL-C and Apo B were significantly lower. Both oral contraceptive preparations were equally effective in suppression of follicular development, but combiphasic DSG/EE induced higher plasma levels of carrier proteins and higher plasma levels of potentially anti-atherogenic lipid parameters than did triphasic LNG/EE.

The effect of postmenopausal estrogen therapy on the risk of non-insulin-dependent diabetes mellitus

OBJECTIVES

This study examined the effect of postmenopausal estrogen replacement therapy on the incidence of non-insulin-dependent diabetes in women.

METHODS

Postmenopausal women aged 50 through 70 years (n=848) without diagnosed diabetes at baseline were followed for 10 to 15 years for incident diabestes.

RESULTS

Over the average 11.5 year follow-ip, there were 105 new cases of diabetes. The age-adjusted relative-risk for development of diabetes was nonsignificantly lower for women with continuous estrogen replacement therapy use than for never users. After adjustment for major covariates, a nonsignificant linear trend with increasing duration of estrogen replacement therapy was reversed.

CONCLUSIONS

This study suggests that previous results showing a reduced risk of diabetes in women using estrogen may have been due to selection bias regarding who is prescribed estrogen, confounding factors, or differential diagnostic efforts.

Metabolic effects of the menopause and oestrogen replacement

There is little doubt that the metabolic disturbances seen following the loss of ovarian function are most important in the development of cardiovascular disease in women. The loss of hormones at the menopause appears to reduce both insulin secretion and elimination, but increasing insulin resistance thereafter brings about an increase in circulating insulin concentrations. Changes in lipids and lipoproteins are in an adverse direction, as are changes in body fat distribution, and changes in haemostatic factors would tend to favour coagulation rather than fibrinolysis. HRT with oestrogen appears to improve most of the metabolic abnormalities related to the menopause, but this is in part dependent on the type of oestrogen used and the route of administration. The addition of progestogen may influence the metabolic changes induced by oestrogens, and this will vary according to the type of the progestogen. Overall, the metabolic effects of any of the current HRT regimens would seem likely to be beneficial for CHD. Nevertheless, future HRT regimens should ideally be tailored to produce the most favourable changes in CHD metabolic risk factors, particularly in the case of the regimens which attempt to avoid cyclical bleeding.

New progestogens in oral contraception

The major developments in combined oral contraceptives (COCs) have been a reduction in the total dose of both the oestrogen and progestogen administered per cycle and the introduction of new progestogens which are claimed to be more 'selective' than the older ones. This review examines in detail the clinical efficacy of the new COCs, where possible in comparison with those containing levonorgestrel or norethisterone, and their pharmacological effect on carbohydrate and lipid metabolism, haematological factors, pituitary-ovarian function and serum protein and androgen concentrations. Based mainly on the pharmacological evidence, the newer COCs are an improvement over the older low-dose formulations and are clearly preferable to the high-dose ones. However, the older low-dose COCs, despite many years of use, have not resulted in a high incidence of adverse effects. The increasing use of the new COCs, as evidenced by their increasing market share throughout Europe, does indicate that they have been well accepted in clinical practice.

Long-term hormone replacement treatment in menopause: new choices, old apprehensions, recent findings

In recent years there has been an increase in the use of parenteral oestradiol as an alternative to the conventional oral preparations used in hormone replacement treatment (HRT) in menopause, such as conjugated equine oestrogens (CEE). The latter have been subject in the past to apprehensions, partly due to misunderstanding and oversimplification but also in relation to problems that have arisen during the history of HRT, for example the increase in endometrial cancer risk deriving from the use of non-progestogen-opposed treatment. However, confidence in long-term HRT comes from the epidemiological findings, which refer mainly to the use of oral CEE unopposed by progestogen: a reduced risk of osteoporotic fractures and of cardiovascular disease, and a very limited risk of breast cancer. Oral oestrogens produce marked hepatocellular effects. These effects are, on the whole, favourable from the point of view of cardiovascular risk. In addition, it cannot be excluded that some hepatocellular effects of oral oestrogen, for example increased sex hormone binding globulin levels and reduced circulating insulin-like growth factor I activity, offer protection to the breast. As progestogen supplementation is needed in non-hysterectomized women, priority should be given to preparations, such as progesterone or dydrogesterone, that feature good endometrial activity without opposing oestrogen hepatocellular effects.

Insulin sensitivity is decreased in normal women by doses of ethinyl estradiol used in oral contraceptives

OBJECTIVE

We determined the independent effects of various doses of ethinyl estradiol used in oral contraceptives or norethindrone acetate, as well as their combination, on insulin sensitivity in normal women.

STUDY DESIGN

Thirty-three normal ovulatory female volunteers were recruited for this study. Insulin tolerance tests were performed after carbohydrate loading to determine the kinetic disappearance of glucose and insulin. After initial testing the women were randomized into four groups: ethinyl estradiol 20 micrograms, 35 micrograms, and 50 micrograms and norethindrone 1 mg. Insulin tolerance tests were repeated after 1 month of treatment and again after a second month, when all ethinyl estradiol groups received the addition of norethindrone 1 mg to their doses of ethinyl estradiol. Plasma glucose and insulin were measured, and insulin sensitivity (K(itt) glucose) and the disappearance of insulin (K(itt) insulin) were calculated.

RESULTS

All groups were comparable at baseline, and no significant changes in fasting glucose and insulin were evident with treatment. After ingestion of 50 micrograms ethinyl estradiol the K(itt) glucose value decreased significantly (p < 0.03) and ingestion of 20 micrograms and 35 micrograms showed individual changes, but as groups the changes were not statistically significant. All ethinyl estradiol groups combined had a significant decrease in K(itt) glucose (p < 0.01). Norethindrone 1 mg alone did not change K(itt) glucose values, and after the addition of norethindrone to ethinyl estradiol, K(itt) glucose values normalized. K(itt) insulin values were also lower with treatment but were lower with ethinyl estradiol plus norethindrone compared with ethinyl estradiol alone (p < 0.04), suggesting an attenuation of insulin clearance with the progestin.

CONCLUSION

Ethinyl estradiol alone decreases insulin sensitivity, and this may occur at lower doses, but norethindrone 1 mg does not appear to do so. However, progestins may alter insulin clearance.

Differential effects of oral conjugated estrogens and transdermal estradiol on insulin-like growth factor 1, growth hormone and sex hormone binding globulin serum levels

In postmenopausal women oral ethinylestradiol causes a reduction in circulating insulin-like growth factor 1 (IGF-1) and an increase in serum growth hormone levels. There are no data on the effect of conjugated estrogens, the preparation most often used in estrogen replacement treatment (ERT), on these parameters. We evaluated serum IGF-1 and growth hormone levels, together with the levels of sex hormone binding globulin (SHBG), an indicator of estrogen hepatocellular action, before and after 6 months of ERT in two comparable groups of postmenopausal women. Sixteen women were treated with oral conjugated estrogens, 0.625 mg/day, and 14 with transdermal estradiol, 0.05 mg/day. In the women treated with oral conjugated estrogens, an increase in SHBG (p < 0.001), a decrease in IGF-1 (p < 0.001) and an increase in growth hormone (p < 0.05) serum levels were observed. No such effects were seen with the use of transdermal estradiol, devoid of hepatocellular effects. Undoubtedly, oral conjugated estrogens, 0.625 mg/day, through a hepatocellular effect, cause marked modifications in the IGF-1/growth hormone axis, which may have clinical relevance. For instance, the decreased IGF-1 level, together with the increased level of SHBG, might provide some explanation of the favorable epidemiological data on breast cancer risk in women receiving oral conjugated estrogens.

Insulin resistance, secretion, and elimination in postmenopausal women receiving oral or transdermal hormone replacement therapy

Estrogen/progestin steroid combinations adversely affect glucose tolerance and insulin resistance, but their effects in combined hormone replacement therapy (HRT) have rarely been evaluated. We studied 61 untreated symptomatic postmenopausal women randomized to receive oral (conjugated equine estrogens, 0.625 mg/d continuous + levonorgestrel, 0.075 mg/d for 12 days of each 28-day cycle) or transdermal therapy (estradiol 17 beta, 0.05 mg/d continuous + norethindrone acetate, 0.25 mg/d for 14 days of each 28-day cycle). An untreated control group of 30 postmenopausal women not seeking HRT was also studied. Intravenous glucose tolerance tests (IVGTT) were performed at baseline and 3, 6, and 18 months later. Mathematical modeling analysis of plasma glucose, insulin, and C-peptide concentration profiles provided measures of insulin resistance, secretion, and elimination. There were no changes in glucose or insulin concentrations with transdermal therapy. Oral therapy caused a deterioration of glucose tolerance and an increased overall plasma insulin response, apparently due to a reduction in the immediate plasma insulin response to glucose. This may have resulted from increased hepatic insulin uptake, uncompensated for by an increase in first-phase pancreatic insulin secretion. Neither treatment caused significant insulin resistance compared with baseline, but with the oral treatment insulin resistance was greater during the combined phase compared with the estrogen-only phase. Thus the oral regimen affected both insulin delivery and insulin resistance. The transdermal regimen had relatively few effects on insulin metabolism.

Progesterone receptor immunoreactivity in pancreatic endocrine tumors. An immunocytochemical study of 156 neuroendocrine tumors of the pancreas, gastrointestinal and respiratory tracts, and skin

BACKGROUND

The immunoreactivity for progesterone receptors (PR) of the majority of endocrine cells of the human pancreas has prompted the authors to investigate if PR expression is maintained in pancreatic endocrine tumors and is correlated with the main clinicopathologic features of these neoplasms. Furthermore, the study has been extended to other neuroendocrine cells and tumors to determine whether PR immunoreactivity is a common feature of neuroendocrine cells and tumors other than those of the pancreas.

METHODS

One hundred fifty six neuroendocrine tumors of the pancreas, gastrointestinal and respiratory tracts, and skin were immunostained for PR with three different monoclonal antibodies and for estrogen receptors (ER). Additional immunostainings for general neuroendocrine markers and for pancreatic hormones were performed in selected cases.

RESULTS

Nuclear immunoreactivity for PR has been documented in the neoplastic cells of 56 (58.33%) of 96 pancreatic endocrine tumors. PR immunoreactivity was not influenced by the sex and age of the patients or the occurrence of a clinical syndrome related to inappropriate hormone secretion. Tumors synthesizing pancreatic polypeptide, glucagon, and insulin expressed PR in higher percentages (80%, 75%, and 66%, respectively) than those producing other pancreatic hormones or those that were not functioning. Irrespective of the functionally different tumor types, PR immunoreactivity showed a significant correlation (P = 0.0003) with the absence of metastases and the lack of tumor invasion of neighboring organs or of large vessels. As opposed to normal and neoplastic islet cells, the neuroendocrine cells and tumors of the gastrointestinal tract, respiratory tract, and skin did not show any PR immunoreactivity, with the single exception of a typical carcinoid tumor of the lung. ER were not identified in any pancreatic or extrapancreatic neuroendocrine cells or tumors.

CONCLUSIONS

Nuclear PR are immunocytochemically detectable in most pancreatic endocrine tumors and are correlated significantly to the absence of pathologic evidence for malignancy. Conversely, PR expression has not been found in normal and neoplastic endocrine cells and tumors investigated.

Lipid and biochemical changes after low-dose oral contraception

A randomized double-blind study of the metabolic effects of 2 low-dose combined oral contraceptives was carried out in Singaporean women. The subjects comprised 58 women randomly allocated to two treatment groups (29 each): norethisterone 1 mg/ethinyl estradiol 35 micrograms (NET/EE) or levonorgestrel 150 micrograms/ethinyl estradiol 30 micrograms (LNG/EE) and a control group of 23 women using intra-uterine devices (IUD). Blood samples were taken on admission and at 3 and 12 months after pills or insertion of IUDs. Fasting glucose levels were decreased while 2h glucose and triglyceride were increased throughout the treatment period in NET/EE group [corrected]. LNG/EE group only showed significant increase of 2h glucose at 12 months and decrease of LDL cholesterol at 3 months while total cholesterol was significantly suppressed at 3 and 12 months [corrected]. The atherogenic index, LDL/HDL cholesterol was significantly reduced by 12 months. Both groups had no change in hemoglobin, hematocrit and total protein levels but alkaline phosphatase, bilirubin and aspartate transaminase (SGOT) were suppressed. While NET/EE suppressed albumin significantly, this was not observed with LNG/EE group. However, these differences observed with use of each pill preparations, were not so obvious between treatment groups and control. Changes in total, HDL and LDL cholesterol and SGOT were not significantly different than the IUD group. Furthermore, except for 2h glucose, there was no increase in the number of abnormal parameters after treatment. On the contrary, there was a reduction of abnormal values in most liver function parameters. Thus, except for glucose intolerance, the observed changes in metabolic parameters may not constitute any clinical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucose tolerance in women: the effects of age, body composition, and sex hormones

OBJECTIVE

To determine the separate and interactive effects of age, phase of the menstrual cycle, menopausal hormone status, body fat mass, and regional fat distribution on glucose tolerance in healthy women.

DESIGN

Retrospective study.

SETTING

The Baltimore Longitudinal Study of Aging.

PATIENTS

Two hundred sixty healthy women aged 22-89 years.

MEASUREMENTS

Plasma levels of estradiol and progesterone, body mass index (BMI), waist-to-hip ratio (WHR), and plasma glucose values in the fasting state (FPG) as well as 120 minutes after 40 gm/m2 of oral glucose (G120) were measured for each participant.

RESULTS

We found a progressive decline in oral glucose tolerance of 0.4 mM (6.7 mg/dL)/decade at G120) in women from early to late adult years, with no relationship to phase of the menstrual cycle and no abrupt change associated with the menopause. Multiple regression analysis revealed significant, independent effects of BMI and WHR on FPG and G120. The influence of age (P less than 0.01) on G120 was stronger than that of the BMI or WHR (P less than 0.05). There was no significant relationship between the levels of endogenous sex hormones and glucose tolerance after adjustments for age, BMI, and WHR. However, women taking oral contraceptives, but not those receiving postmenopausal replacement therapy, did exhibit mildly elevated G120 values.

CONCLUSIONS

Age per se, and to a lesser extent BMI and WHR, but not levels of endogenous sex steroids, contribute to the physiological decline in glucose tolerance in older women.

The effect of continuous subdermal levonorgestrel (Norplant) on carbohydrate metabolism

Blood glucose and plasma insulin levels during an oral glucose tolerance test were measured in 20 women using continuous subdermal levonorgestrel (Norplant) for contraception over a 12-month period. Changes in carbohydrate metabolism occurred as early as 1 month but were most marked after 6 months. After 1 month the area under the glucose and insulin curves increased by 12.3% and 37.7%, respectively. This increase was more marked by 6 months, but by 12 months it was significantly less marked. Although changes in the blood glucose and plasma insulin levels at different times during the oral glucose tolerance test occurred, they were all within normal limits for normal women. The peak blood glucose and insulin levels after insertion of the implant occurred 60 minutes after the glucose load, as opposed to 30 minutes before insertion. Apart from this, there was a significant delay in the return of these levels to fasting values. We conclude that this product, like any other progesterone-containing contraceptive, alters carbohydrate metabolism, but these alterations are not clinically significant in normal women. It is, however, possible that in potential cases of diabetes it may predispose to frank diabetes.

Contraception for women with diabetes: an update

Today several effective contraceptive methods are available for women with IDDM. Contraceptive guidance as part of the pre-pregnancy counselling needs to be more widely implemented by general practitioners and in non-specialized obstetrical and gynaecological departments. Women with diabetes are generally well motivated, and thus the barrier methods may prove both acceptable and reliable contraceptive agents for some of these women. When, however, a high risk of user failure can be predicted, the IUD or hormonal contraception may be the only reversible alternative. According to our findings, IUDs can be recommended without reservation to women with IDDM. In women with previous GDM it seems that low dose oral contraceptive compounds may be administered without running the risk of inducing glucose intolerance, but long-term results are still unavailable. Natural oestrogens may be administered in combination with a progestogen for a limited period as an efficient and acceptable mode of contraception in women with IDDM without any concomitant adverse effects on diabetic control. From our investigations it also appears that short-term administration of combined low dose OCs containing the traditional progestogens (e.g. norethisterone or levonorgestrel) or the new gonane progestogens (e.g. gestodene) does not alter glycaemic control in women with IDDM. Similarly, these compounds do not cause any significant changes in lipid/lipoprotein levels during short-term treatment, although the intake of monophasic ethinyloestradiol/norethisterone preparations may result in higher triglyceride levels and tends to increase lipid levels more than triphasic ethinyloestradiol/levonorgestrel compounds. The results from our clinic have shown that OCs can be safely recommended at pre-conception counselling so that women with diabetes can obtain both optimal glycaemic control and efficient spacing of their pregnancies.

An open prospective study on the effects on carbohydrate metabolism of an oral monophasic contraceptive containing gestodene (WL-70)

The effects of a monophasic oral contraceptive (gestodene 75mcg + ethinylestradiol 30 mcg) on plasma glucose (PG) and insulin (IRI) responses to an oral glucose load (OGTT) and on glycosylated haemoglobin Alc (HbAlc), fructosamine (Fr), total cortisol (FT) and transcortin (CBG) were studied in 30 healthy women. Blood samples were taken before treatment and after 6 and 12 cycles. After 6 and 12 months, OGTT-PG and IRI levels showed substantially unchanged values; for HbAlc and Fr the same behaviour was seen with the exception of the latter between 6 and 12 months; FT and CBG showed significant rises. All recorded values were in the normal range. The basal and dynamic PG and IRI behaviour failed to show any significant variations between pre-treatment values and those after 6 and 12 months of OC administration. Other data showed a substantial neutrality for this oral contraceptive containing gestodene.

Prodrugs: advantage or disadvantage?

Our knowledge of the peculiarities of prohormones is rather limited, both pharmacologically and clinically. Generalizations cannot be made except that the lapse of time until peak blood values of the active drug have been reached are always greater after intake of the prodrug than after intake of the drug. This finding is presumably of no clinical importance. If pharmacokinetic differences are limited to the phase of distribution, bioequivalence may be assumed. If, on the other hand, the area under the curve during the elimination phase is smaller for the prodrug than for the drug, the potency of the former should be decreased. A shift in the spectrum of endocrine actions as a result of the biotransformation of the prodrug into the active drug is rather the exception than the rule, and so is a change in side effects. If there are major differences in this respect, metabolic pathways in addition to those leading to the respective active drug must also be taken into consideration.

Effect of low-dose oral contraceptives on carbohydrate and lipid metabolism in women with recent gestational diabetes: results of a controlled, randomized, prospective study

Women with recent gestational diabetes mellitus were randomly assigned to one of two low-dose oral contraceptives to evaluate the effect of low-dose oral contraceptives on carbohydrate and lipid metabolism. A cohort of similar women requesting a non-oral-contraceptive method served as controls. The two oral contraceptives studied were ethinyl estradiol (0.035 mg)-norethindrone (0.40 mg) and ethinyl estradiol (0.030 to 0.040 mg)-levonorgestrel (0.050 to 0.125 mg). A 75 gm, 2-hour oral glucose tolerance test and a fasting lipid profile (total cholesterol, triglyceride, high- and low-density lipoprotein cholesterols) were performed at entry, after 3 months, and after 6 to 13 months of treatment. The prevalence of diabetes at 6 to 13 months (27/156 patients) was not significantly different between groups (non-oral-contraceptive group, 17%; ethinyl estradiol-norethindrone, 15%; ethinyl estradiol-levonorgestrel, 20%). When examined by prior gestational diabetes mellitus class, diabetes mellitus was present in 7% of prior class A1 and 29% of women with prior class A2 disease (p less than 0.001). Mean cholesterol and low-density lipoprotein cholesterol levels were significantly improved in all three groups at 3 months and at 6 to 13 months, whereas triglycerides remained unchanged. There were no differences in cholesterol, low-density lipoprotein cholesterol, or triglycerides levels between the groups. After 6 to 13 months, there was a significant increase in high-density lipoprotein cholesterol in the ethinyl estradiol-norethindrone group compared with the ethinyl estradiol-levonorgestrel and non-oral-contraceptive groups.

Hormonal changes in cerebral infarction in the young and elderly

Fifty-one patients with CCT verified cerebral infarction were submitted to serum and CSF radioimmunoassay of FSH, LH, estradiol (E2), progesterone, testosterone, cortisol and T4. The results were compared to those of 82 matched controls. Our findings suggest that (1) high serum E2 is a risk factor of stroke in males; (2) low serum T4 is a risk factor in males; (3) serum testosterone is reduced in acute stroke in males confirming that it is stress sensitive; (4) serum LH was higher in hypertensive thrombotic males when compared to normotensive ones, and (5) FSH, LH, E2 and T4 are undetectable in CSF of patients and controls.

Clinical aspects of the relationship between oral contraceptives, abnormalities in carbohydrate metabolism, and the development of cardiovascular disease

Although large epidemiologic studies indicated no difference in the frequency of diabetes mellitus in nonusers and everusers of high-dose combination oral contraceptives, other studies had shown an increased risk of impaired glucose tolerance in current users, which is estimated to be roughly twice as frequent as that in nonusers. Women at risk of developing impaired glucose tolerance while receiving high-dose oral contraceptives either had previous gestational diabetes mellitus or were older, obese, or had a positive family history of diabetes mellitus. The tendency to decreased glucose tolerance seems essentially related to the dosage and chemical structure of the progestogen used in oral contraceptives, namely, estrane and particularly gonane progestins. However, increased frequency of impaired glucose tolerance and potentially diabetes mellitus are obviously not linked to the use of the more potent gonane progestins. The use of low-dose oral contraceptives, particularly with reduced progestogen content (such as in the triphasic formulations and last-generation monophasic preparations), is accompanied by a low risk of impaired glucose tolerance, even in previous gestational diabetes mellitus. The mechanism of decreased glucose tolerance in oral contraceptive users is unknown but seems related partially to increased peripheral resistance that is potentially caused by a postreceptor defect in insulin action. Changes in insulin production or metabolic clearance rate are not excluded by recent, sophisticated investigations of carbohydrate metabolism in oral contraceptive users. Impaired glucose tolerance and diabetes mellitus, chronic hyperglycemia, and hyperinsulinemia are believed to increase atherogenic risk either by their direct action or their effects on lipid metabolism. Newer epidemiologic studies now indicate that the incidence of cardiovascular disease in low-dose, low-risk, current oral contraceptive users has been substantially decreased. The use of low-dose oral contraceptives with reduced dosages of better adapted progestogens seems effective in decreasing alterations in carbohydrate metabolism and may thereby contribute to decrease further atherogenic risk in oral contraceptive users.

Mechanism of action of oral contraceptives on carbohydrate metabolism at the cellular level

Although the available scientific data on the undesired metabolic effects of sex steroids have accumulated rapidly, most are of a descriptive nature, and only a few studies elucidate the impact at the cellular level and the possible interrelationship between different metabolic systems. This review summarizes the influence of different contraceptive steroid combinations on glucose metabolism and points to the possible mechanisms behind a disturbance of the euglycemic homeostasis with a concomitant change in lipid metabolism. Today the general concept is that the influence of combined sex steroid products on glucose metabolism is mainly caused by the progestogen components, although artificial estrogens may act synergistically. The diabetogenic effects of the progestogens make it important to consider the development during the last decade of the new more selective progestogens of the gonane type. From recent studies it seems, however, that intake of contraceptive combinations of ethinyl estradiol in combination with these types of gonanes, such as desogestrel and gestodene, may also be accompanied by increased insulin resistance, specifically, a hyperinsulinemic response to a glucose challenge despite unchanged glucose values compared with a baseline test. This is similar to observations made with combinations of ethinyl estradiol and other more traditional types of progestogens of the gonane and estrane type. It is conceivable that the diabetogenic effects of the progestogens are caused by a change in insulin receptor binding or a postreceptor defect in the cellular insulin action. The clinical implications of the diabetogenic effects of the sex steroids are hard to interpret, but more long-term exposure of arterial tissue to elevated concentrations of glucose and insulin results in inhibition of lipolysis and synthesis of cholesterol and triglycerides, which result in the development of lipid-filled lesions--fatty streaks--similar to those of early atherosclerosis.

Carbohydrate metabolism during hormonal substitution therapy

Oestrogens and progestogens are known to influence glucose tolerance. Impairment of glucose tolerance is seen in particular among users of progestogens with androgenic properties. Dydrogesterone is frequently used as the progestogen adjunct during oestrogen substitution therapy for the management of climacteric complaints in post-menopausal women. However, no detailed data have been published concerning its effects on carbohydrate metabolism. In this study, 20 healthy post-menopausal women received equine oestrogens at a dose of 0.625 mg/day for 2 mth, following which dydrogesterone was added cyclically (20 mg/day for 12 days/mth) over a period of 6 mth. Oral glucose tolerance tests were performed before and after each treatment regimen. In relation to the concentrations observed after oestrogen was given alone, dydrogesterone induced only a small increase in blood insulin values which was not statistically significant. The effect was similar to that produced by endogenous progesterone, which is known to be of no clinical significance.

Alterations in carbohydrate metabolism as they apply to reproductive endocrinology

This review has characterized the current state of knowledge of four clinical situations in which an interrelationship of gynecology, endocrinology and carbohydrate metabolism is recognized. The literature contains conflicting descriptions of changes in glucose homeostasis during the menstrual cycle and while using birth control pills. Physiologic changes in receptor number have been demonstrated in each of these situations, so failure to observe differences using glucose tolerance testing may reflect an in vivo homeostatic response to changes in these hormone levels. Thus, in vivo identification of alterations in carbohydrate metabolism induced by endogenous or exogenous steroids may require utilization of models that prevent these homeostatic mechanisms. The association between hyperandrogenism and hyperinsulinism has been better characterized, but the relationship is complicated by the frequent coexistence of obesity. The association may be due to insulin-stimulated ovarian androgen production, and insulin insensitivity may reflect a postreceptor defect. Insulin and its metabolic effects have also been implicated in ovulatory dysfunction in women with diabetes mellitus and identified as a factor affecting all levels of the hypothalamic-pituitary-ovarian axis. A clearer understanding of these relationships and their application to clinical management await further study.

Metabolic effects of oral contraceptives

Combination oral contraceptives (OCs) are probably not an independent risk factor for cardiovascular disease but through their metabolic actions, may partly amplify the effects of known risk factors for cardiovascular disease. This review of the literature and our own data indicate that use of high-dose, progestogen-dominant OCs induces a potentially atherogenic lipoprotein profile (high low-density lipoprotein-cholesterol:high-density lipoprotein-cholesterol ratio), mostly attributable to the antiestrogenic action of the progestogen content of these OCs. In contrast, lower-dose combination OCs with reduced amounts of progestogens and slight estrogen dominance, either monophasic or multiphasic, produce strikingly fewer adverse effects on lipoproteins. Moreover, use of low-dose, as opposed to high-dose, OCs results in almost unchanged glucose tolerance, marginally increased or unchanged insulin and glucagon responses to glucose, and probably unchanged levels and activity of peripheral insulin receptors. Further in-depth studies of low-dose OC formulations are mandatory to ascertain reduced metabolic risk of these OCs.

Effect of seven low-dose combined oral contraceptive preparations on carbohydrate metabolism

The effect of seven low-dose oral contraceptive preparations on carbohydrate metabolism was investigated in groups of 10 healthy volunteers. All preparations contained a similar amount of ethinyl estradiol but differed in the content and type of progestogen. The following progestogens were used: levonorgestrel (monophasic and triphasic), norethisterone (monophasic), cyproterone acetate (monophasic), desogestrel (monophasic and biphasic) and gestodene (triphasic). An oral glucose tolerance test was performed before and after 6 months of treatment; glucose disappearance and insulin response curve were determined. Long-term glucose homeostasis was assessed by the estimation of the extent of glycosylation of plasma proteins and hemoglobin A1. The area under the curve for insulin and glucose did not change during treatment with any of the preparations. In addition the representative variables for long-term glucose control did not increase for any of the preparations during treatment. We conclude from these results that the low-dose pills investigated in this study do not have any adverse effects on glucose metabolism after treatment for 6 months.

Glucose and lipid metabolism with triphasic oral contraceptives in women with history of gestational diabetes

The glucose and lipid metabolism in a group of women with previous history of gestational diabetes were evaluated before and after 6 months treatment with a low-dose triphasic oral contraceptives pill (TP). This group was compared with a control group of women, also with history of gestational diabetes, using intrauterine devices (IUD). In the TP group, 26.7% of the women developed impaired glucose tolerance which reverted to normal in all but one after cessation of the TP. The IUD group showed no change in glucose tolerance. The integrated insulin response to a 75g OGTT in the TP group increased by 48.3% at 6 months compared with an increase of 23.4% for the same period in the IUD group. In the TP group there was a significant decrease in serum total cholesterol without changes in HDL-cholesterol and triglycerides level. We conclude that even low-dose triphasic oral contraceptive pills can cause glucose intolerance in women with previous gestational diabetes mellitus.

Effects of natural oestrogen/progestogen substitution therapy on carbohydrate and lipid metabolism in post-menopausal women

Oral glucose tolerance tests were performed in 30 post-menopausal women before and after 1 mth and 6 mth of cyclic 17 beta-oestradiol/norethisterone acetate substitution therapy. Before undergoing treatment the patients were divided into three groups comprising subjects with normal glucose tolerance, subjects with impaired glucose tolerance and diabetic subjects receiving oral diabetic treatment respectively. Carbohydrate metabolism was evaluated during a 2-h oral glucose tolerance test following a 100 g glucose load. Both blood glucose and plasma insulin values were measured. The fasting serum cholesterol and triglyceride levels were also determined. Hormone substitution therapy had no effect on fasting blood glucose values in any of the three groups. At the end of the 6 mth substitution therapy, however, it was found that the blood glucose values in the subjects with impaired glucose tolerance were significantly lowered by the end of the 2-h test period. The glucose areas under the curve during oral glucose tolerance tests following the hormone treatment were also reduced in this same group. In the case of insulin, the areas under the curve remained unchanged in all three groups. Fasting serum cholesterol levels tended to fall, while the triglyceride levels remained unaltered, during the hormone treatment periods. However, a slight increase in triglyceride levels was observed in the subjects with impaired glucose tolerance.

Carbohydrate metabolism in women who used oral contraceptives containing levonorgestrel or desogestrel: a 6-month prospective study

Blood glucose and pyruvate, plasma insulin, and glucagon levels as well as erythrocyte insulin receptors were measured during an oral glucose tolerance test in 38 normal women before and after 6 months' use of one of three new oral contraceptives containing low doses of 19 nortestosterone-derived progestogens, levonorgestrel, and desogestrel. A slight deterioration of glucose tolerance was observed, with the area under the glucose curve increasing by only 7%, 9%, and 12% after Ovidol (Aaciphar SA, Brussels, Belgium), Marvelon (Organon, SA, Brussels, Belgium), and Trigynon (Schering SA, Brussels, Belgium) administration, respectively. We did not find any argument in favor of the development of a state of insulin resistance in women using these compounds, because erythrocyte receptor binding was not modified and plasma insulin responses to glucose were decreased. The glucose-induced suppression of plasma glucagon levels seemed less effective for treatment with the desogestrel-containing preparations than with the levonorgestrel-containing oral contraceptives.

A randomized cross-over comparison of two low-dose oral contraceptives upon hormonal and metabolic serum parameters: II. Effects upon thyroid function, gastrin, STH, and glucose tolerance

The effect of a low-dose triphasic oral contraceptive (OC) containing ethinyl estradiol and levonorgestrel (EE/NG) upon thyroid function and some other biochemical serum parameters was compared to that of a preparation containing EE and desogestrel (EE/DG). Blood samples were taken on Day 6, 11, 21, and 28 of a control cycle and of the third cycle of treatment with either the EE/NG or EE/DG preparation (11 volunteers each). After a washout period of 3 months, the contraceptives were changed in a cross-over fashion. Blood samples were again taken on Day 6, 11, 21, and 28 of the third washout cycle and the third treatment cycle. There was a significant increase (13%) in basal glucose level during treatment with both OC, but no change in glucose tolerance. Both the EE/NG and FE/DG preparation elevated serum T4 (40%), FT4 (15-22%), T3 (17-28%), and TBG (20%) significant, whereby the effect was more pronounced during the second treatment period after washing-out. The effective thyroxine ratio (ETR) was slightly (4%) but significantly increased. Contrary to this, the levels of FT3, reverse T3 (rT3), TSH, and gastrin were not altered. STH showed great individual fluctuations, but was significantly elevated by 50% during treatment with both OC. There was no effect of endogenous estradiol upon thyroid or other parameter, even though it was raised considerably in some women under OC. Although the increase in T4 and T3 is probably due to a rise in estrogen-induced TBG production, the data seem to indicate that there is a slight but effective stimulation of thyroid function during treatment with low-dose OC.

Oral glucose tolerance and the potency of contraceptive progestins

Two-hour oral glucose tolerance test results from the Walnut Creek Contraceptive Drug Study, a 10-year prospective follow-up study on the metabolic and medical effects of the "pill," were analyzed to determine the contribution of six progestins and synthetic estrogen to an observed decrease in glucose tolerance. Glucose tolerance data and specific oral contraceptive formulation data were obtained for 354 oral contraceptive users and 1732 nonusers. Multiple linear regression analyses, using age, body mass index, and specific progestin and estrogen dosages as independent variables, were undertaken to define dose-response relationships between the contraceptive steroids and fasting, 1-hr and 2-hr glucose values. The results of these analyses were consistent with the observation that the mean 1- and 2-hr values were higher in users of the "pill." The 16% prevalence of impaired glucose tolerance in pill users was substantially higher than that of 8% in the nonusers. Examination of the regression coefficients suggested that one progestin (norgestrel) was more metabolically "potent" than the others. The remaining progestins appeared to have either a modest or no metabolic effect, in terms of 1- and 2-hr glucose values. Synthetic estrogens were shown not to be related to measures of glucose tolerance.

Effect of oral contraceptives on plasma glucose, insulin, and glucagon levels

Effects of oral contraceptive agents (mestranol and norethindrone) on carbohydrate metabolism were evaluated in a group of 18 healthy young women. Plasma glucose, insulin, and glucagon responses were evaluated after a glucose load (oral and intravenous) and an amino acid challenge (oral and intravenous). The oral glucose tolerance was normal and was unaltered by the use of oral contraceptive agents. However, following intravenous administration of glucose, plasma glucose levels were slightly but significantly elevated when subjects were using oral contraceptives. Plasma insulin concentrations were slightly but significantly higher than control values in response to oral and intravenous administration of glucose while subjects were using oral contraceptives. Plasma glucagon concentrations in response to oral and intravenous glucose were similar whether the subjects were using oral contraceptive agents or not. No significant differences from control values were observed after oral and intravenous amino acid challenges when subjects were using oral contraceptive agents. Mild elevations of glucose and insulin without any significant change in glucagon concentrations suggest that glucagon levels do not play a major role in the development of insulin resistance seen in some patients using oral contraceptive agents.