Effects of oral contraceptives on free fatty acid metabolism in women

These studies examined whether women using oral contraceptives have abnormalities in free fatty acid (FFA) metabolism compared with women not using oral contraceptives. Plasma palmitate kinetics ([3H]palmitate) were measured at rest, following glucose ingestion, and during epinephrine infusion in 13 oral contraceptive users and 13 matched women not using oral contraceptives. Oral contraceptive users had significantly greater plasma triglyceride concentrations and glucose responses to oral glucose tolerance testing. No differences in basal (2.1 +/- 0.1 v 1.8 +/- 0.2 micromol x kg fat-free mass x FFM(-1) x min[-1]), glucose-suppressed (0.6 +/- 0.1 v 0.5 +/- 0.1 micromol x kg FFM(-1) x min[-1]), or epinephrine-stimulated (3.3 +/- 0.1 v 3.6 +/- 0.2 micromol x kg FFM(-1) x min[-1]) palmitate flux were detected between women using and not using oral contraceptives. The respiratory quotient (RQ) also was not different between groups. We conclude that the increase in plasma triglycerides and the mild glucose intolerance seen with oral contraceptive use is not associated with significant abnormalities of FFA metabolism.

The effect of oral contraceptive agents on the basal metabolic rate of young women

The use of oral contraceptive agents by women may be a factor that contributes to the observed inter-individual variability in the BMR. We, therefore, measured the BMR, body build and composition in two groups of young women and also assessed their self-reported level of physical activity. One group had been using oral contraceptive agents for a period of 6 months or more (OCA, n 24), while the other group had never used oral contraceptives (NOCA, n 22). There were no significant differences in age, body build or composition. The absolute BMR in the groups were not significantly different when compared using an unpaired t test (OCA: 5841 (SD 471) v. NOCA: 5633 (SD 615) kJ/d). However, using an analysis of covariance, with either body weight or a combination of fat and fat free mass as covariates, the OCA group had a BMR almost 5% higher than that of the NOCA group (OCA: 5871 v. NOCA: 5601 kJ/d; P = 0.002). When those subjects with high self-reported levels of physical activity were excluded, the difference in BMR between the two groups persisted (P = 0.001). An ANOVA of oral contraceptives use and phase of menstrual cycle showed significant differences in BMR with use of oral contraceptives (P = 0.004) but no difference in BMR between phases of the menstrual cycle. In conclusion, the use of oral contraceptive agents deserves consideration when conducting and analysing data from studies on energy metabolism in young women, as it results in a significantly higher BMR.

Oral contraceptive effects on methylprednisolone pharmacokinetics and pharmacodynamics

OBJECTIVE

Oral contraceptive (OC) steroids alter the disposition of numerous drugs, including corticosteroids. We investigated the pharmacokinetics and pharmacodynamics of methylprednisolone.

METHODS

Twelve women (six women used OC steroids and six women did not) received intravenous methylprednisolone (0.6 mg/kg ideal body weight). Methylprednisolone disposition was assessed from plasma concentrations. Pharmacodynamic parameters measured were plasma cortisol, whole blood histamine (reflecting basophils), and blood helper T lymphocytes.

RESULTS

Methylprednisolone clearance was significantly decreased in the women who used OC steroids (0.298 versus 0.447 L/hr/kg), resulting in a longer elimination half-life (2.20 versus 1.72 hours). With use of indirect response models, significant differences were observed with the cortisol and basophil responses. A larger value for the concentration that inhibits the zero-order production rate by 50% (0.37 versus 0.11 ng/ml) was observed in the women who used OC steroids for suppression of cortisol secretion, indicating less sensitivity to the suppressive effects of methylprednisolone. Greater net suppression of basophils was observed in the users of OC steroids (area under the response curve, 694 versus 401 ng x hr/ml). No differences were observed for helper T-cell responses.

CONCLUSION

OC steroids appear to inhibit methylprednisolone metabolism. However, mixed changes in several responses occur, indicating that women can probably receive similar doses of methylprednisolone irrespective of OC steroid use.

Designer contraceptive pills

The present world population of 5.6 billion is projected to reach 9 billion by the year 2025. Overpopulation remains one of the overwhelming issues of the 21st century, but only limited effort and resources have been allocated to designing new contraceptives, as evidenced by the diminished interest of the pharmaceutical industry and funding agencies. Major advances have been made recently in our understanding of the genetic basis of an individual's risk to various reproductive cancers and sex steroid-related diseases. It has also become apparent that agonistic and antagonistic analogues of sex steroids with tissue-specific actions can be formulated. These new insights provide the opportunity to develop the next generation of 'designer' contraceptive pills with disease-prevention benefits.

Effect of two oral contraceptives containing ethinylestradiol and gestodene or norgestimate upon androgen parameters and serum binding proteins

The effect of a triphasic oral contraceptive containing ethinylestradiol and gestodene (EE/GSD) on various serum hormonal parameters was compared with that of a monophasic formulation containing 35 micrograms ethinylestradiol and 250 micrograms norgestimate (EE/NGM). Blood samples were collected from 46 women on days 2, 11, and 21 of the preceding control cycle and of the third, sixth and twelfth treatment cycle. There was no significant difference in the influence on any hormonal parameter between both formulations. Both EE/GSD and EE/NGM caused a time-dependent suppression of serum dehydroepiandrosterone sulphate (DHEA-S) by 20-30% (p < 0.01) and a reduction of 5 alpha-androstane-3 alpha, 17 beta-diol glucuronide by 50-60% (p < 0.01) during each treatment cycle, while androstenedione levels were reduced by 25% (p < 0.01). There was also a significant decrease in the levels of total testosterone by 30-35% (p < 0.01) and free testosterone by 60% (p < 0.01), while sex hormone-binding globulin (SHBG) was increased by 200-240% on days 11 and 21 (p < 0.01). During the pill-free interval the SHBG levels were reduced to a certain degree but remained elevated by 100% as compared to the pretreatment values. The serum levels of corticosteroid-binding globulin (CBG) which is known to be influenced only by the estrogenic component of combination pills, increased significantly by 170% (p < 0.01) during each treatment cycle. During the pill-free interval of 7 days, the CBG levels decreased but were still elevated by 90-100% as compared to the control cycle. Similarly, the serum levels of cortisol were significantly elevated by 110-140% (p < 0.01) during treatment with both preparations. The results demonstrate a profound suppression of androgen levels and peripheral androgen metabolism.

Effects of sex steroids on women's health: implications for practitioners

Androgen excess in women is manifested typically by clinical features that may include hirsutism, acne, central obesity, male-pattern baldness, upper torso widening, increased waist-to-hip ratio, clitoral hypertrophy, and deepening of the voice. The differential diagnosis includes androgen-producing ovarian and adrenal neoplasms, Cushing's syndrome, polycystic ovary syndrome, and the intake of exogenous androgens. Physicians treating patients for one symptom of androgen excess must be alert for other symptoms and signs. The cosmetic manifestations of androgen excess belie the serious health risks associated with this condition, including cardiovascular disease, intravascular thrombosis, and insulin resistance. Prompt clinical recognition of androgen excess, understanding of the androgen-related biochemical abnormalities underlying the risks associated with this condition, and implementation of risk modification can reduce the incidence of associated morbidity and mortality. An interdisciplinary approach to management is strongly recommended. Risk reduction strategies include correction of dyslipidemias, low-dose aspirin for primary prevention of myocardial infarction, maintenance of ideal weight, smoking cessation, exercise, use of oral contraceptives containing a low-androgenic progestin, and postmenopausal estrogen replacement. Combination oral contraceptives containing low-androgenic progestins are effective not only in reducing signs of androgen excess but also in potentially retarding the progression of long-term sequelae such as cardiovascular disease.

Update on the metabolic effects of steroidal contraceptives and their relationship to cardiovascular disease risk

Evaluation of metabolic disturbances has had an important role in the modification of oral contraceptive formulations toward estrogen-progestin combinations with reduced adverse metabolic impact. An increasing number of interrelationships between metabolic risk factors for cardiovascular disease are being recognized, and a metabolic syndrome of disturbances has been identified with insulin resistance as a potential underlying factor. The insulin resistance syndrome includes hyperinsulinemia and impaired glucose tolerance, hypertriglyceridemia, reduced high-density lipoprotein concentrations, and hypertension. Increased concentration of a small, dense, low-density lipoprotein subtype may also be important. Depending on steroid type and dose, combined oral contraceptives may induce all the features of the insulin resistance syndrome. Reduction in estrogen dose and modification of progestin content have resulted in formulations with no adverse effect on high-density lipoprotein and blood pressure, but insulin resistance and hypertriglyceridemia remain. These are caused primarily by the estrogen component. Therefore modification of the estrogen content of oral contraceptives might result in "metabolically transparent" formulations that could conceivably afford a degree of cardiovascular protection.

Administration of RU 486 for 8 days in normal volunteers: antiglucocorticoid effect with no evidence of peripheral cortisol deprivation

New therapeutic indications based on the antiprogesterone action of RU 486 (Mifepristone) are emerging which require long term administration and raise the question of its safety because of the antiglucocorticoid action of the drug. A trial was designed to assess the antiglucocorticoid effect of RU 486, possible manifestations of peripheral cortisol deprivation, and the adrenocortical and corticotroph reserves. Ten normal male volunteers (aged 21-29 yr) were given RU 486 (200 mg/day) or placebo between 0800-0900 h for 8 consecutive days in a randomized, double blind, cross-over design, with a 1-month interval between the two periods. RU 486 induced overactivation of the pituitary-adrenal axis; baseline values (mean +/- SEM) before and at end of treatment were, respectively: 0800 h plasma cortisol, 147.3 +/- 15.5 and 257.6 +/- 8.8 ng/mL; 0800 h salivary cortisol, 5.8 +/- 1.2 and 15.2 +/- 0.8 ng/mL; nocturnal (2200-0800 h) urinary cortisol, 8.4 +/- 1.5 and 33.7 +/- 11.1 micrograms; and 0800 h plasma ACTH, 29.2 +/- 3.7 and 60.2 +/- 8.4 pg/mL. All of these variations were significantly different from those during placebo treatment (0.0001 < P < 0.03) and disappeared within 4 days after the end of treatment. A daily record of subjective clinical symptoms, body weight and temperature, blood pressure, and heart rate showed neither side-effects nor any significant variation during treatment. Blood electrolyte and eosinophil counts were unchanged; fasting blood glucose was slightly higher at the end of treatment (5.0 +/- 0.2 vs. 4.7 +/- 0.1 mmol/L; P = 0.04). The adrenocortical response to Cortrosyn (0.25 mg, im) was exaggerated during RU 486 treatment (P < 0.006): peak values before and at the end of treatment were, respectively: plasma cortisol, 272.5 +/- 15.2 and 347.1 +/- 20.6 ng/mL; and salivary cortisol, 17.0 +/- 2.2 and 31.1 +/- 3.1 ng/mL. Direct pituitary stimulation (100 micrograms ovine CRH, followed by 1 IU lysine vasopressin over 15 min) also induced exaggerated corticotroph and adrenocortical responses (P < 0.005); peak values before and at the end of treatment were, respectively: plasma ACTH, 147.7 +/- 24.6 and 254.0 +/- 41.3 pg/mL; and plasma cortisol, 231.6 +/- 7.3 and 319.2 +/- 12.3 ng/mL. These data show that 8-day treatment with 200 mg RU 486 daily induces a hormonally detectable antiglucocorticoid effect without clinical symptoms. This state results from reversible cortisol overproduction with preservation of adrenocortical and pituitary reserves.

FDA requirements for nonclinical testing of contraceptive steroids

Written guidelines for the preclinical testing of contraceptive steroids have not been revised since 1968 despite the fact that many important changes have been implemented by the FDA's Division of Metabolism and Endocrine Drug Products. This paper describes the new preclinical testing requirements and the rationale for their implementation.

Interrelationship of serum levonorgestrel and sex hormone-binding globulin levels following vaginal and oral administration of combined steroid contraceptive tablets

Ten women were treated daily with a standard dose contraceptive tablet containing 0.25 mg levonorgestrel (LNG) in combination with 0.05 mg ethinylestradiol. Five women used the tablet vaginally, while the other five used it orally. Blood samples were taken at frequent intervals on the first day of treatment and after 1 and 2 hours on treatment days 7 and 14. Serum LNG levels were measured by radioimmunoassay, and sex hormone-binding globulin (SHBG) was quantitated by charcoal assay. On day 1, peak concentrations of LNG (5.1 ng/ml) occurred within 2 hours in the oral group, whereas in the vaginal group a peak of 2.2 ng/ml was reached after 4 hours. After 24 hours, mean serum concentrations of LNG were 1.1 and 0.69 ng/ml in the oral and vaginal groups, respectively. In both groups, mean LNG concentrations increased dramatically on days 7 and 14 compared to day 1. There was no significant difference between the two groups in LNG concentrations, except after 2 hours on day 1. SHBG levels were increased after one day of treatment. By day 14 of treatment, there was a 3.5- to 4.5-fold rise in SHBG levels from pretreatment values in both groups. However, there was no significant difference in SHBG levels between the two groups throughout the study. A high correlation was found between serum levels of SHBG and LNG in both the vaginal and oral groups. The results suggest that the increase in serum LNG levels in women receiving combined contraceptive tablets either vaginally or orally is due to increased levels of SHBG. Also, the measured concentrations of LNG in the vaginal group are consistent with the previously reported clinical contraceptive efficacy of combined contraceptive tablets administered vaginally.

Effects of nomegestrol acetate (5 mg/d) on hormonal, metabolic and hemostatic parameters in premenopausal women

The effects of nomegestrol acetate on circulating hormone levels, metabolic and hemostatic parameters and blood pressure were studied in 36 premenopausal women. The progestogen was administered from day 7 to 25 of the cycle during six cycles at a dosage (5 mg/d) known to inhibit ovulation. Analysis were performed before and in the third and sixth cycles. Estradiol and progesterone levels decreased significantly (p less than 0.001) during treatment. Body weight, fasting blood glucose and insulin, total HDL and LDL cholesterol, apolipoprotein B, fibrinogen and plasminogen did not change significantly. Triglycerides in the third cycle (p less than 0.05) and apolipoprotein A1 levels (p less than 0.01) in both periods of sampling decreased significantly. There was a significant increase in antithrombin III (p less than 0.01). These results indicate that nomegestrol acetate has no deleterious effect on blood glucose and lipids. The decrease in apolipoprotein A1 and increase in antithrombin III may be related either to the decrease in estradiol levels induced by the treatment or to the effect of the progestogen itself.

Hirsutism: metabolic effects of two commonly used oral contraceptives and spironolactone

Fifty-one hirsute women were randomly treated for nine months with ethinyl estradiol 35 ug plus norethindrone 0.4 mg or 30 ug ethinyl estradiol plus 1.5 mg norethindrone acetate if they needed contraception or spironolactone 200 mg daily if they did not. Metabolic evaluations in response to therapy demonstrated triglyceride elevations with the two oral contraceptives but not with spironolactone. While systolic blood pressure was lower with spironolactone, fasting insulin levels were higher as opposed to either low-dose oral contraceptive preparation. Ethinyl estradiol 30 ug plus 1.5 mg norethindrone acetate lowered 3-alpha-diol glucuronide levels, yet ethinyl estradiol 35 ug plus norethindrone 0.4 mg and spironolactone were more effective in lowering Ferriman-Gallwey Scores. Treatment strategies for hirsute women need to consider metabolic consequences as well as efficacy.

The pharmacokinetics of ethynylestradiol in the presence and absence of gestodene and desogestrel

Single doses of ethynylestradiol (30 micrograms) were given alone and in combination with either gestodene (75 micrograms) or desogestrel (150 micrograms) to 10 healthy female volunteers. The doses of steroids were given both orally and by i.v. infusion over 5-7 minutes. Blood samples were taken at regular intervals over 24 hours. The area under the plasma concentration versus time curve (AUC) for oral EE2 alone was 867 +/- 338 pg/ml x h, for oral EE2 in the presence of gestodene it was 795 +/- 206 pg/ml x h and for oral EE2 in the presence of desogestrel it was 614 +/- 132 pg/ml x h. With either gestodene or desogestrel present, the AUC of EE2 was not significantly different from that found when EE2 was given alone. In addition, there was no significant difference between EE2 + gestodene and EE2 + desogestrel. Comparing the relative oral and iv doses, the bioavailability of EE2 (alone) was 59.0 +/- 13% (n = 6), for EE2 plus gestodene it was 62.1 +/- 10% and for EE2 in the presence of desogestrel it was 62.1 +/- 4.4%. The clearance of EE2 (alone) was 19.9 +/- 5.5 l/h and in the presence of gestodene it was 19.4 +/- 9.6 l/h. The clearance of EE2 in the presence of desogestrel appeared slightly greater at 27.7 +/- 8.9 l/h but none of these clearance values were significantly different from each other. The urinary excretion of 6-beta-hydroxy cortisol was similar after all 6 doses of EE2. These data strongly suggest that following single dose administration, neither gestodene nor desogestrel have any inhibitory effect on the metabolism of EE2 or alter its kinetics to any clinically significant extent.

A neutrophilic reaction of Sweet's syndrome type associated with the oral contraceptive

A case is presented of a Sweet's syndrome-like eruption in association with the oral contraceptive. A 46 year old caucasian woman developed recurrent episodes of erythematous tender plaques on her trunk six weeks after commencement of the oral contraceptive (OC). Her condition clinically and histologically resembled Sweet's dermatosis. On cessation of the OC there was complete resolution of her lesions and she remains well 12 months later. This is the first report, to our knowledge, of a neutrophilic reaction to the oral contraceptive, and we believe that drugs may be implicated in the aetiology of atypical neutrophilic reactions simulating Sweet's syndrome in patients who are otherwise well.

Oral contraceptives and coronary heart disease

In industrialized countries, coronary heart disease (CHD) is a major public health problem for both men and women. Preventive strategies for reducing the excessive mortality and morbidity associated with CHD involve the identification and modification of metabolic factors believed to be involved in the disease process. Three major areas of concern are lipid metabolism, carbohydrate metabolism and the hemostatic system. The steroid hormones contained in oral contraceptives (OCs) have been shown to interfere in all three areas. In many instances OCs have been shown to alter metabolic markers for CHD in directions associated with increased risk. Although evidence is lacking that such changes induce CHD in users of modern, low-dose OCs, it would be prudent to develop formulations with a minimal impact on metabolic risk markers. There is increasing evidence that many of the metabolic disturbances seen in CHD patients share a common origin, and the development of risk-free OCs is likely to require investigation into complex interrelationships.

Effect of the progestogens, gestodene, 3-keto desogestrel, levonorgestrel, norethisterone and norgestimate on the oxidation of ethinyloestradiol and other substrates by human liver microsomes

A number of different progestogens, levonorgestrel (LNG), norethisterone (NET), gestodene (GSD), desogestrel (DG) and norgestimate (NORG) are used in combination with the oestrogen ethinyloestradiol (EE2) in oral contraceptive steroid preparations. All the progestogens are acetylenic steroids and previous studies have indicated the potential of acetylenic steroids to cause mechanism-based or "suicide" inactivation of cytochrome P-450. We have compared the effects of the different progestogens on EE2 2-hydroxylation (a reaction catalyzed by enzymes from the P-450IIC, P-450IIIA and P-450IIE gene families) and also the oxidative metabolism of other drug substrates (cyclosporin, diazepam, tolbutamide) by human liver microsomes. On coincubation with EE2 as substrate, GSD, 3-keto desogestrel (3-KD, the active metabolite of desogestrel) and LNG produced some concentration-dependent inhibition of EE2 2-hydroxylation (maximum 32% inhibition at 100 microM 3-keto desogestrel). Ki values determined for GSD and 3-KD were 98.5 +/- 12.3 and 93.2 +/- 10.3 microM (mean +/- SD; n = 4), respectively. Preincubation of progestogens in a small volume (50 microliters) incubation for 30 min in the presence of an NADPH-generating system enhanced the inhibitory potential of all the steroids (at 100 microM, inhibition was for GSD 39%, 3-KD 46%, LNG 46%, NET 51% and NORG 43%). Inhibitory effects were therefore comparable and also similar to the macrolide antibiotic troleandomycin. The most marked inhibition seen was of diazepam N-demethylation and hydroxylation by GSD (71 and 57%, respectively) and 3-KD (62 and 50%, respectively). In preincubation studies involving cyclosporin as the substrate, the order of inhibitory potency was GSD greater than 3-KD greater than NET greater than LNG for production of both metabolite M17 and M21. The results of the study indicate that all the progestogens in common use have the propensity to inhibit a number of oxidative pathways but there is little evidence for one progestogen being more markedly inhibitory than others.

Interactions with oral contraceptives

The interaction of a range of different factors with the pharmacologic activity of oral contraceptives is reviewed. Pharmacokinetic interactions with oral contraceptives may occur (1) during absorption and extrahepatic circulation, (2) by interfering with protein binding, and (3) during hepatic metabolism. The hepatic mixed function oxidase system, which is mainly responsible for the metabolism of oral contraceptives, is affected by several different factors and is easily induced. Nutrition affects the activity of many drugs, but information regarding oral contraceptives is meager. Both pharmacokinetic and pharmacodynamic interactions, which may be synergistic or antagonistic, between the estrogen and gestagen components of oral contraceptives, are important, but there is no correlation between the rate of metabolism of the two components. Evidence suggests that some anticonvulsant, antibiotic, and antibacterial drugs may reduce the efficacy of oral contraceptives. Instances of interactions of other therapeutic agents are reported infrequently. The incidence of serious interactions is low and does not appear to have been reduced with low-dose oral contraceptives, probably because of large intersubject variability in the pharmacokinetics of oral contraceptives.

Gastrointestinal disease and oral contraception

Oral contraceptive steroids play a major role in modern family planning. With the present tendency to decrease the doses of both estrogens and progestogens, any factor that reduces the bioavailability of the lower-dose preparations may have an impact on contraceptive protection. Although ethinyl estradiol, the most commonly used oral estrogen, is liable to an enterohepatic circulation as unchanged drug, the commonly used progestogens are not. At present, no convincing evidence exists in the human subject that disruption of the enterohepatic circulation by antibiotics or antacids does reduce contraceptive efficacy of the pill. Oral contraceptive steroids are mainly absorbed from the small bowel, and contraceptive efficacy depends on its absorptive capacity. Enhanced passage of gastrointestinal contents or impaired absorption may thus contribute to contraceptive failures in patients who have chronic inflammatory disease, diarrhea, ileostomy, or jejunoileal bypass.

Gastrointestinal metabolism of contraceptive steroids

A number of oral contraceptive steroids undergo first-pass metabolism in the gastrointestinal mucosa. Ethinyl estradiol (mean systemic bioavailability 40% to 50%) is extensively metabolized, principally to a sulfate conjugate. In vivo studies that use portal vein catheterization and the administration of radiolabeled ethinyl estradiol have shown that the fraction of steroid metabolized in the gut wall is 0.44. In vitro studies with jejunal biopsy samples or larger pieces of jejunum or terminal ileum mounted in Ussing chambers have indicated that more than 30% of added ethinyl estradiol is sulfated. The progestogen desogestrel is a prodrug that is converted to the active metabolite 3-ketodesogestrel. Substantial first-pass metabolism of desogestrel occurs in the gut mucosa, with evidence from Ussing chamber studies for the formation of the active metabolite. Another progestogen, norgestimate, is also metabolized by the gut wall in vitro of which the principal metabolite is the deacetylated product, norgestrel oxime. It seems very likely that this will also occur in vivo. Drug interactions occurring in the gut wall have been reported with ascorbic acid (vitamin C) and paracetamol.

A pharmacodynamic and pharmacokinetic study of the Chinese No. 1 pill

A pharmacodynamic and pharmacokinetic study of the Chinese No. 1 pill, a combined oral contraceptive containing 35 micrograms ethynyloestradiol (EE) and 600 micrograms norethisterone (NET), was performed in 29 women over a period of six months. Blood samples for analysis were taken during a pretreatment cycle, the first and 6th treatment cycles and post-treatment. Minor changes in carbohydrate metabolism occurred and these were particularly noticeable when the incremental areas under the serum concentration-time curves for both glucose and insulin in response to a glucose tolerance test were calculated. No changes occurred in the serum glycosylated haemoglobin levels. The serum concentrations of all the lipids measured (total cholesterol, triglycerides, LDL-C, HDL-C and apolipoproteins AI, AII and B) were significantly increased on treatment as were levels of Factor X, SHBG and caeruloplasmin whereas antithrombin III decreased. In 38 of the 40 treatment cycles, ovulation was suppressed. In one cycle serum oestradiol and progesterone levels showed a typical ovulatory pattern and in another there was evidence of follicular activity without ovulation. Serum EE concentrations showed a similar pattern in both treatment cycles showing that co-administration of NET did not affect EE metabolism. Serum NET levels were higher in the 6th than in the first treatment cycles. On comparing pharmacodynamic and pharmacokinetic parameters, the only statistically significant correlations were between the percentage change in triglycerides and SHBG and serum NET, but not EE concentrations, and between apolipoproteins AI and serum EE.

Intra- and interindividual variations in contraceptive steroid levels during 12 treatment cycles: no relation to irregular bleedings

During one year of treatment with oral contraceptives containing 30 micrograms ethinylestradiol and 150 micrograms desogestrel (EE/DG) or 30 micrograms EE and 75 micrograms gestodene (EE/GSD), the serum concentrations of EE, 3-keto-desogestrel (KDG) and GSD were determined on day 1, 10 and 21 of the 1st, 3rd, 6th and 12th cycle. The areas under the time-versus-concentration curves were calculated from the levels before and 0.5, 1, 1.5, 2, 3, 4 and 24 hours after intake of a tablet. There were large intra- and interindividual variations both revealing coefficients of variation (C.V.) between 25% and 80% (EE),, 30% and 50% (KDG) and 30% and 65% (GSD). During each cycle, the EE levels increased significantly between day 1 and 10 by 70% on average reaching a steady-state, while the progestogen concentrations rose by 100% (KDG) and 150% (GSD) up to a steady-state between day 10 and 21. After reaching the steady-state, the C.V. were generally lower. The ratios between the levels of EE and the progestogens showed still higher variations indicating different influences on the estrogen and progestogen component. There was no correlation between the steroid levels and weight, height or age. In spite of the large intraindividual variations, most of the women showed a distinct pattern of the levels of EE and the progestogens throughout the year of treatment indicating a genetic or acquired predisposition. The difference in the average AUC of EE, KDG and GSD between the women was 300% at most. During the first cycle of treatment with EE/DG and EE/GSD, about half of the women recorded intermenstrual bleedings which decreased thereafter. There was no relation between the occurrence of irregular bleedings and the average serum levels of EE and the progestogens of the individual women, neither during the first cycle nor during the whole treatment period of 12 cycles. It is concluded that spottings or breakthrough bleedings during treatment with oral contraceptives are not dependent on a distinct pattern of the serum levels of EE and the progestogen.

Pharmacokinetics of oestrogens and progestogens

There are large inter- and intra-individual variations in the serum concentrations of natural and synthetic sex steroids irrespective of the route of administration. Oral ingestion of steroids has a stronger effect on hepatic metabolism than parenteral administration, as the local concentration in liver sinusoids are 4-5 times higher during the first liver passage. Oestradiol and oestrone are interconvertible, dependent on the local concentrations in liver and target organs, and oestrone sulphate serves as a large reservoir. The oestrone/oestradiol ratio has no physiological significance, as oestrone is only a weak oestrogen. Oestrone is both a precursor and a metabolite of oestradiol. Oestriol is extensively conjugated after oral administration. Therefore, the oestriol serum levels are similar after oral intake of 10 mg and after vaginal application of 0.5 mg oestriol resulting in similar systemic effectiveness. Conjugated oestrogens can easily enter the hepatocytes but are hormonally active only after hydrolyzation into the parent steroids. Ethinylestradiol which exerts strong effects on hepatic metabolism and inhibits metabolizing enzymes, should not be used for hormone replacement therapy. Among the progestogens, the progesterone derivatives have less effects on liver metabolism than the norethisterone derivatives (13-methyl-gonanes and 13-ethyl-gonanes). The highly potent 13-ethyl-gonanes are effective at very low doses, because of a slow inactivation and elimination rate due to the ethinyl group.

Metabolism of the contraceptive steroid desogestrel by human liver in vitro

The metabolism of the progestogen oral contraceptive desogestrel (Dg) has been studied in vitro using human liver microsomes. Metabolites have been separated using radiometric high performance liquid chromatography and identified by co-chromatography with authentic standards and by mass spectrometry. All the livers examined (n = 6) were able to form 3-keto desogestrel as the main identifiable metabolite and also the presumed intermediates 3 alpha-hydroxydesogestrel (3 alpha-OHDg) and 3 beta-hydroxydesogestrel (3 beta-OHDg). In addition, a large polar heterogenous peak was evident on the radiochromatograms which did not co-chromatograph with any known metabolites of desogestrel. Inter-individual variability in metabolite formation was seen. A number of drugs were examined for their propensity to inhibit desogestrel metabolism. Primaquine was the most potent tested having an IC50 value (inhibitory concentration reducing overall metabolite production by 50%) of 30 microM. Cimetidine, trilostane and levonorgestrel failed to inhibit at 250 microM. With 3 alpha-OHDg as substrate, 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSDH) activity was 1.0 +/- 0.3 nmol min-1 mg-1 protein which was five times greater than the activity of the 3 beta-HSDH towards 3 beta-OHDg. Miconazole was the most potent inhibitor tested having IC50 values of 14 and 95 microM for 3 alpha- and 3 beta-HSDH respectively. Surprisingly, trilostane was without inhibitory effect on either enzyme, which contrasts with other data involving 3 beta-HSDH in steroidogenic tissue. Our observations with trilostane may reflect tissue differences in the enzyme and/or differences in endogenous vs exogenous steroids (i.e. in the conversion of 3 beta-OHDg to 3-ketodesogestrel there is no requirement for isomerization). Kinetic parameters of 3 alpha-HSDH were also determined.

Metabolic effects of low-dose fluconazole in healthy female users and non-users of oral contraceptives

1. Azole antifungal agents such as ketoconazole act by inhibiting cytochrome P-450 mediated sterol synthesis in the fungal cell membrane and thus have the potential to interfere with mammalian steroidogenesis. Fluconazole is a novel orally-effective antifungal triazole which has been reported to have more specific effects on the cytochrome P-450 enzymes involved in fungal sterol synthesis. 2. Due to the potential value of systemic antifungal agents in the treatment of infections commonly occurring in women, we assessed the effect of oral fluconazole on the metabolic profile of 18 healthy premenopausal women, 10 of whom were taking combined oral contraceptives (OC). Each woman acted as her own control, being studied both before and 21-28 days after fluconazole therapy (50 mg daily), in the luteal phase of consecutive menstrual cycles. 3. The endocrinological profile included measurement of serum oestradiol, progesterone, testosterone and sex hormone binding globulin (SHBG) concentrations, short tetracosactrin adrenal stimulation test and thyroid function tests. Carbohydrate metabolism was investigated by means of an oral glucose tolerance test with measurement of plasma glucose, insulin and C-peptide concentrations. Serum lipids, lipoproteins and apolipoproteins were analysed on samples taken after an overnight fast. 4. Minor biochemical changes associated with fluconazole treatment included increases in serum thyroxine and testosterone concentrations (but not in women taking OC as well as fluconazole) and in insulin and apolipoprotein B levels (but only in women taking OC as well as fluconazole). In general, these changes were small and of no clinical significance with the values remaining within the laboratory normal range. There were no adverse side-effects.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of steroids on the fine structure of the endometrium

This brief review illustrates the lack of ultrastructural studies on human endometrium, particularly on well-dated material from normal, fertile women. The glandular epithelium, with its triad of unusual organelles in the early luteal phase, poses fascinating problems in cell biology and, probably for this reason, has attracted the most work. Many problems in reproductive biology, in uterine pathology and in the study of unexplained infertility are crying out for detailed study of the luminal epithelium, the stroma and the blood vessels. If this review, by highlighting the gaps in our knowledge, stimulates research into these areas, it will have been successful.

Metabolism of the contraceptive steroid desogestrel by the intestinal mucosa

1. The intestinal mucosal metabolism of the progestogen oral contraceptive desogestrel (Dg) has been studied in vitro using the Ussing chamber technique. Histologically normal ileum or colon was obtained from eight patients undergoing various resections. The mucosal sheets were mounted between two perspex chambers. 2. Two hours after addition of [3H]-Dg (0.2 microCi; 100 ng) to the mucosal chamber, more than 90% of the steroid was present in that chamber. In studies with colon, metabolite analysis showed that 55.4 +/- 11.7% (mean +/- s.d.; n = 6) of drug present was Dg, 28.9 +/- 11.4% as unconjugated Phase I metabolites, 13.3 +/- 2.6% as sulphate conjugates and 2.5 +/- 1.5% as glucuronide conjugates. 3. By co-chromatography with authentic metabolites and mass spectrometry, it was shown that 3-keto desogestrel is formed in the mucosa. This is the active metabolite of desogestrel. A large peak of radioactivity did not co-chromatograph with any known metabolites and has been tentatively identified as ring hydroxylated products of 3-keto desogestrel. 4. The effect of the synthetic oestrogen ethinyloestradiol (EE2) on the metabolite profile of Dg was studied. In the presence of increasing concentrations of EE2 (100 ng, 1 and 10 micrograms), there was competition for sulphation such that the sulphate fraction decreased by 32, 49 and 48% respectively. 5. The results of this study indicate substantial first pass metabolism of desogestrel by the gut mucosa with evidence for the formation of the active metabolite. The extent of phase I metabolism is unusual.

Some metabolic and hormonal changes in women using long acting injectable contraceptives

Some metabolic and hormonal changes in women using longacting injectables as a contraceptive method were examined. The 2 main injectables utilized were depomedroxyprogesterone acetate (DMPA), given every 90 +or- 5 days, and norethisterone enanthate (NET/EN) injected every 60 +or- 5 days. None of the studied cases became pregnant during injectable use, indicating the high contraceptive efficacy of the method. No statistically significant changes were observed in hemoglobin, hematocrit, all protein fractions including albumin, alpha1, alpha2 beta, gamma immunoglobulins IgG, IgA, and IgM after 6 and 12 months in both groups of injectable users as compared with the preinjection values. Statistically significant suppression of the estimated hormones, Follitropin, Luteotropin, and Estradiol-17beta were detected in both groups of NET/EN and DMPA users, after 6 and 12 months, as compared with the preinjection values.

Effects of age, gender and oral contraceptives on intramuscular midazolam pharmacokinetics

The effects of age, gender and low-dose (50 mcg or less) oral contraceptive steroids (OCS) on the pharmacokinetics of midazolam were evaluated following a single 7.5 mg intramuscular dose to five groups (8/group) of healthy volunteers consisting of young males, young females, elderly males, elderly females, and young female users of oral contraceptives. Blood samples were collected at specified times over a 24-hour period, and plasma concentrations of midazolam and its 1-hydroxymethyl metabolite were determined by a GC-EC assay. Midazolam was rapidly absorbed following intramuscular administration to the different groups. Comparison of young men vs elderly men, young women vs elderly women, young men vs young women, elderly men vs elderly women, and young women OCS-users vs young women non-OCS users indicated no substantial differences in the pharmacokinetic profile of midazolam between groups except for the comparison between the young and elderly men groups. The rate of elimination of midazolam was significantly slower in the elderly males compared to the young men. The pharmacokinetic profile of 1-hydroxymethyl midazolam paralleled that of the parent compound. This is to be expected since this metabolite exhibits formation rate-limited kinetics. Except for one subject who reported hives and itching, considered to be remotely related to test drug, no other adverse experiences or laboratory abnormalities were reported.

Dynamics of estradiol and testosterone and seminal fluid indexes in smokers and nonsmokers

The serum levels of estradiol (E2) and testosterone (T), the metabolic clearance rates of estradiol (MCRE2) and testosterone (MCRT), and the production rates of estradiol and testosterone (PRE2) and (PRT) were examined in 22 male smokers and 21 male nonsmokers. Seminal fluid indexes (sperm count, % motility, grade of motility, and % of sperm with abnormal morphology) were also assessed. The mean E2 level and the mean PRE2 were significantly greater in smokers than in nonsmokers (P less than 0.001 and P less than 0.01, respectively); however, the means of MCRE2, MCRT, PRT, and T did not differ significantly in smokers compared to nonsmokers. No significant product-moment correlations were found between the various hormonal measures and the seminal fluid indexes in the overall sample. However, the smokers with sperm counts below the median sperm count of the sample had significantly higher mean levels of E2 and PRE2 than did the smokers with sperm counts above that median. Mechanisms that might mediate the greater PRE2 of smokers and a negative relationship between estradiol and sperm count are discussed.

The evaluation of the data collection process for a multicenter, population-based, case-control design

This report details the methods the authors used to conduct the Cancer and Steroid Hormone Study, a multicenter, population-based, case-control study of oral contraceptive use in relation to breast, endometrial, and ovarian cancer diagnosed during 1980-1982. The authors have documented their methods and rationale, and the results of their data collection efforts as a practical guide for the planning and conduct of large case-control studies. They observed the following: 1) the Surveillance, Epidemiology, and End Results program is a useful epidemiologic resource for identifying cases from which to evaluate risk factors for cancer in the United States; 2) random digit dialing is an effective and efficient method for screening for eligible controls for a population-based study; 3) with the cooperation of community pathologists, histologic specimen slides can be retrieved and reviewed for diagnostic confirmation and histologic subclassification of cancer for greater than 95% of the cases interviewed; and 4) data reported during personal interviews of study participants can be validated by reviewing medical records for more than 75% of study participants who reported medical events that occurred during the 10 years before the beginning of the study.

The antiglucocorticoid and antiprogestin steroid RU 486 suppresses the adrenocorticotropin response to ovine corticotropin releasing hormone in man

The glucocorticoid and progesterone antagonist RU 486 normalizes the clinical and biochemical features of hypercortisolism in patients with nonpituitary Cushing's syndrome, presumably by antagonizing the action(s) of cortisol. Since RU 486 has progesterone agonist activity in addition to its progesterone antagonist action, the possibility that it might have some glucocorticoid agonist action did not seem unreasonable. To test this hypothesis we examined the effects of RU 486 on pituitary ACTH secretion in 10 patients with primary adrenal insufficiency in whom glucocorticoid replacement was withheld for 36 h. Each patient received, in randomized sequence 3-7 days apart, an oral dose of placebo, RU 486 (20 mg/kg), cortisol (0.1 mg/kg), or a combination of RU 486 and cortisol at 1800 h. Two hours later, an iv bolus dose of ovine CRH (1 microgram/kg) was administered, and plasma ACTH levels were measured serially for 3 h. RU 486 suppressed ovine CRH-stimulated ACTH secretion, albeit less than cortisol. Its glucocorticoid agonist effect was calculated to be approximately 1/250th that of cortisol on a weight basis. Additionally, RU 486 partially antagonized cortisol-induced suppression of ACTH secretion. These findings suggest that RU 486 is a partial glucocorticoid agonist and offer some insight as to its action in patients with Cushing's syndrome. Whether this degree of glucocorticoid agonist activity is adequate to support life, however, is not known.

Effect of administration and withdrawal of oral contraceptive pills on serum lipids and lipoproteins

We studied the effects of oral contraceptive pills (OCP) supplied by the Govt of India in its Family Welfare Campaign, on serum lipid levels of women. The OCP, containing 30 micrograms ethinyl estradiol and 1 mg of norethisterone acetate were administered to the women for six months continuously and serum lipid levels were estimated after three and six months of the treatment. There were no significant changes in serum cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), serum triglycerides and very low density lipoprotein (VLDL). In a simultaneous study we also measured serum lipid levels at 3 and 6 months after withdrawal of the pills in women who had been receiving OCP containing 50 micrograms of ethinyl estradiol and 0.5 mg of one of the progesterones for the past 1 1/2 to 2 years continuously. Only serum LDL level fell significantly (P less than 0.01) on 3 months withdrawal period. It is concluded that 6 months of usage of the OCP marketed by the Govt. of India does not affect the serum lipid profile.

The interaction of alcohol consumption and oral contraceptive use on lipids and lipoproteins

Oral contraceptive (OC) use and alcohol consumption have been shown to alter the levels of lipids and lipoproteins in the blood. The effect of alcohol consumption on levels of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, LDL-B, Apo-A1, the ratio of HDL cholesterol/total cholesterol, HDL cholesterol/LDL cholesterol, and the ratio of LDL cholesterol/LDL-B among normal healthy young women before initiation of oral contraceptives and after six months of oral contraceptive use are both described. Of primary interest is the mediating effect of alcohol consumption on the association between steroid usage and blood lipid values. At baseline, ethanol consumption was found to be positively associated with triglycerides, HDL-C, and Apo-A1 and negatively associated with LDL-C/LDL-B. After adjustment for several covariables, alcohol consumption was found to be positively associated with the increases in triglycerides and in Apo-A1 observed at 3 and 6 months after initiation of OCs. Since these two parameters are believed to have opposite relationships to cardiovascular disease, the effect of alcohol consumption remains uncertain.

Oral contraceptive-induced changes in plasma lipids: do they have any clinical relevance?

The plethora of published studies investigating oral contraceptive pill (OC)-induced changes of various plasma lipids and their ratios together with repeated reviews of these studies in the literature, are all based on the assumption that OC-induced favourable or unfavourable lipid profiles decrease or increase a pill-associated cardiovascular risk. Some authorities have been led to recommend choice of pill formulations based on such changes of plasma lipids. In a combined review of relevant cardiovascular and OC epidemiological studies no evidence is found for these assumptions and recommendations. There is no evidence of OC-induced atherosclerotic disease, and pill-induced changes of plasma lipids within normal limits are therefore probably without any clinical relevance. Profound changes towards a so-called favourable plasma lipid profile may, on the contrary, be detrimental in terms of pill-associated cardiovascular events.

Paracetamol interaction with oral contraceptive steroids: increased plasma concentrations of ethinyloestradiol

The effect of a single dose of paracetamol (1 g) on plasma concentrations of the oral contraceptive steroids ethinyloestradiol (EE2) and levonorgestrel (LNG) has been studied in six healthy female volunteers. The area under the plasma concentration-time curve (AUC0-24) of EE2 was significantly increased following paracetamol administration by 22% (control 2221 +/- 291; following paracetamol, 2702 +/- 452 pg ml-1 h; mean +/- s.d.; P less than or equal to 0.05). The greatest effect was evident in the time period 0-3 h. There was a significant decrease in the AUC of EE2-sulphate after paracetamol (7736 +/- 3791 pg ml-1 h) compared with control (13161 +/- 4535 pg ml-1 h; P less than or equal to 0.05). Plasma concentrations of LNG were unaltered by concurrent paracetamol administration. We conclude that the administration of a single 1 g dose of paracetamol causes an increase in plasma concentrations of EE2 as a result of a reduction in the sulphation of the steroid. This interaction may be of clinical significance in women on oral contraceptive steroids who regularly take paracetamol.

The characterization of sulphated metabolites of norethindrone in human milk after oral administration of contraceptive steroids

The excretion of ethynyl steroids in milk from a lactating woman taking a daily dose of an oral contraceptive (Conlumin) containing 1 mg of norethindrone and 50 micrograms of mestranol has been studied. Milk was diluted with aq. triethylamine sulphate and steroids were extracted on a Sep-Pak C18 cartridge at 60-64 degrees C. Groups of unconjugated steroids, glucuronides, mono- and disulphates were separated on triethylaminohydroxypropyl Sephadex LH-20. Following hydrolysis and further purification, steroids possessing an ethynyl-substituent were isolated by chromatography on sulphohydroxypropyl Sephadex LH-20 in silver form. Gas chromatographic-mass spectrometric analysis of the O-methyloxime-trimethylsilyl ether derivatives of these steroids, showed the presence of norethindrone and mestranol in the free fraction and of tetrahydro metabolites of norethindrone with 3 alpha,5 alpha, 3 alpha,5 beta and 3 beta,5 alpha configurations in the mono- and disulphate fractions. The disulphate of the 3 alpha,5 alpha isomer was the most abundant ethynyl steroid in milk after 13 days of administration. The site of conjugation of the monosulphates was established by acetylation prior to solvolysis and analysis by gas chromatography-mass spectrometry. This showed that the 3 alpha,5 alpha isomer was conjugated mainly in the 17 beta-position while the 3 alpha,5 beta isomer was conjugated at C-3.

Serum ovarian steroids, prolactin and prostaglandin metabolites in women using the inert intrauterine device

Serum levels of 17 beta estradiol, progesterone, prolactin and metabolites of prostaglandins E2 and F2a were investigated in 18 healthy women before and after the insertion of a Saf-T-Coil intrauterine device. The results suggest that the presence of an intrauterine device may cause hormonal changes affecting the luteal phase of the menstrual cycle.

The relative bioavailability of levonorgestrel and ethinyl estradiol administered as a low-dose combination oral contraceptive

The relative bioavailability of levonorgestrel (LNG) and ethinyl estradiol (EE) administered concomitantly both as an oral tablet and as a solution was assessed in a randomized two-period crossover study in 24 healthy women. Serum concentrations were monitored for 96 h after each administration. The relative bioavailability (Fr) of LNG in the tablet with respect to the solution was 107%; thus the two formulations were bioequivalent with respect to LNG. The relative bioavailability of EE, however, was significantly lower for the tablet (Fr 83%) compared to the solution. This difference may have been due to either decreased absorption or enhanced presystemic elimination of EE from the tablet formulation.

Selection of steroid combinations for oral contraceptives of maximum benefit

Low-dose oral contraceptives differ in the specific progestin component. Our review of available animal and human data revealed differences between the progestins as to their potencies for estrogenic, anti-estrogenic, androgenic and progesterone effects. Ideally, oral contraceptive formulations should have the minimal effective dose, sufficient to prevent pregnancy but with the fewest metabolic changes. The risk of cardiovascular disease may be predicted by changes in the composition and amount of circulating lipoproteins. Progestins with significant androgenic potency can lower high-density lipoprotein2; that is a possible adverse effect. Randomized, blind, comparative trials of the new multiphasic preparations are needed to determine which ones truly cause the fewest metabolic changes that might be of clinical significance.

Influence of gender and oral contraceptive steroids on the metabolism of salicylic acid and acetylsalicylic acid

Salicylic acid and acetylsalicylic acid (aspirin) disposition after an oral dose of aspirin, 900 mg (equivalent to 689.7 mg of salicylic acid) was studied in eight males, eight females and eight females receiving oral contraceptive steroids (OCS). Salicylic acid clearance was 61% higher in males compared to the control female group, an effect due largely to enhanced activity of the glycine conjugation pathway (salicyluric acid formation) in males. Salicylic acid clearance was 41% higher in OCS-users compared to the control female group due to increases in both the glycine and glucuronic acid conjugation pathways in the pill users. There was no difference in any salicylic acid disposition parameter between males and OCS-users. Area under the plasma concentration-time curve (AUC) and elimination half-life of aspirin was significantly greater and aspirin plasma hydrolysis rate was significantly lower in both female groups compared to males. There was no difference between OCS-users and the control female group in any of these parameters. Aspirin AUC and elimination half-life were significantly correlated with aspirin plasma hydrolysis rate. These data confirm the importance of hormonal factors in the regulation of drug conjugation reactions in humans and suggest that sex-related differences in salicylic acid and aspirin disposition may be of clinical importance.

Serum levels of progesterone and some of its metabolites including deoxycorticosterone after oral and parenteral administration

Single 100-mg doses of progesterone were given orally and as intramuscular injections to four women during the follicular phase of the menstrual cycle. After oral administration serum levels of progesterone increased rapidly to reach luteal phase values (mean maximum level 55.6 nM) within 1-4 h and were still elevated after 12 h. The serum concentrations of 20 alpha-hydroxy-4-pregnen-3-one showed a similar pattern while there were only minor transient changes in 17 alpha-hydroxyprogesterone concentrations. The serum levels of cortisol and 4-androstene-3,17-dione were unaffected. In comparison, after intramuscular administration values two to three times higher than by the oral route were achieved. A significant increase in serum deoxycorticosterone was recorded in all women. The mean ratio between the change in deoxycorticosterone and progesterone was increased after oral administration. Oral treatment with natural progesterone may develop into an attractive alternative to synthetic progestogens but the conversion of progesterone into a potent mineralocorticoid may be a potential disadvantage.

The new steroid analog RU 486 inhibits glucocorticoid action in man

RU 486 [17 beta-hydroxy-11 beta-(4- dimethylaminophenyl )-17 alpha-(prop-1- ynyl )-estra-4,9-dien-3-one] is a new steroid analog which antagonizes glucocorticoid action at the receptor level in animals. To assess its potential antiglucocorticoid activity in man we studied the pituitary-adrenal response to RU 486 in normal men. The compound was administered at 0200 h and plasma cortisol and lipotropins (LPH) were measured hourly for 10 h. After 400 mg RU 486 significant and sustained elevation of both hormones occurred during the 0700-1200 h period: mean (+/- SE) plasma levels after placebo or RU 486 during this interval were, respectively, for cortisol (ng/ml), 63.4 +/- 8.2 and 112.7 +/- 2.9 (P less than 0.02); and for LPH (pg/ml), 34.8 +/- 11.3 and 71.6 +/- 15.4 (P less than 0.01). The 200- and 100-mg doses induced only transient cortisol and LPH increases. Administration of RU 486 (400 mg) at 1400 h induced no increase in plasma cortisol compared to placebo in the corresponding 2000 to 2400 h period. When RU 486 was administered concomitantly with dexamethasone (1 mg) at 2400 h, dose-dependent blockade of the dexamethasone-induced cortisol suppression at 0900 h was found (r = 0.62, P less than 0.01); this blockade was partial after the 100-mg dose, but complete after the 400-mg dose. Plasma LPH and ACTH showed parallel variations. We conclude that RU 486 antagonizes the negative pituitary feedback of both the nocturnal endogenous cortisol rise and exogenously administered dexamethasone. These actions are consistent with an antiglucocorticoid activity of this compound in man.

Danazol binding to steroid receptors in human uterine endometrium

To understand the mechanism of action of danazol, the binding of danazol to multiple classes of intracellular steroid binding proteins was studied in the human uterine endometrium. Danazol bound to endometrial receptors for estrogen, progesterone, and androgen and seemed to bind to endometrial intracellular corticosteroid-binding globulin and sex-hormone-binding globulin. Danazol occupies almost all binding sites of steroids in the steroid target cells in spite of the presence of endogenous steroids. It is speculated that the binding behavior of danazol may be related to its therapeutic effect on endometriosis.