Dietary calcium intake and rates of bone loss in women.

We measured bone mineral density (BMD) at the midradius and lumbar spine in 106 normal women, ages 23-84 yr (61 were postmenopausal). Three to nine measurements (median, four) were made over 2.6 to 6.6 yr (mean, 4.1 yr). The correlation between calcium intake (range, 260-2,035 mg/d) and rate of change in BMD was not significant at the midradius (r = 0.06) or lumbar spine (r = 0.08), even after adjusting for age, menopausal status, and serum estrogen levels by multiple regression analysis. Women in the lower (mean, 501 mg/d) and in the upper (mean, 1,397 mg/d) quartiles of dietary intake had similar rates of change in BMD (%/yr [mean +/- SE], at midradius, -0.78 +/- 0.24 and -0.91 +/- 0.17 for lower and upper quartiles, respectively; at lumbar spine, -1.06 +/- 0.24 and 0.98 +/- 0.24). These data do not support the hypothesis that insufficient dietary calcium is a major cause of bone loss in women.

Characterization of the inappropriate gonadotropin secretion in polycystic ovary syndrome.

To evaluate gonadotropin release in polycystic ovary syndrome (PCO), one or more of the following hypothalamic-pituitary function tests were performed on 24 patients with the syndrome. These tests included (a) the pulsatile pattern and day-to-day fluctuation of gonadotropin release; (b) effects of exogenous estrogen and antiestrogen (clomiphene) administration on gonadotropin release; and (c) pituitary responsiveness to maximal (150 mug) and submaximal (10 mug) luteinizing hormone-releasing factor (LRF) injections. In 10 of the 14 patients sampled frequently (15 min) for 6 h, luteinizing hormone (LH) levels were elevated above the concentration seen in normal cycling women (except the LH surge). These high LH concentrations appeared to be maintained by and temporally related to the presence of exaggerated pulsatile LH release, either in the form of enhanced amplitude or increased frequency. In all subjects, levels of follicle-stimulating hormone (FSH) were low or low normal, and a pulsatile pattern was not discernible. In four patients, daily sampling revealed marked day-to-day fluctuation of LH but not FSH. That the elevated LH levels were not related to a defect in the negative-feedback effect of estrogen was suggested by the appropriate fall of LH in four patients given an acute intravenous infusion of 17beta-estradiol. This infusion had no effect on FSH levels. In addition, clomiphene elicited rises of both LH and FSH that were comparable to the ones observed in normal women given the same treatment. The clomiphene study also suggested that the positive-feed-back mechanism of estrogen on LH release was intact when the preovulatory rises of 17beta-estradiol induced appropriate LH surges. The elevated LH levels appeared to be related to a heightened pituitary responsiveness to the LRF. This was found in the 11 and 2 patients given maximal (150 mug) and submaximal (10 mug) doses of LRF, respectively. The augmented pituitary sensitivity for LH release correlated with the basal levels of both estrone (P less than 0.025) and 17beta-estradiol (P less than 0.02). The net increase in FSH was significantly greater (P less than 0.001) in the PCO patients than the normal women with maximal doses of LRF. With the smaller dose study none of the injections had a discernible effect on FSH concentrations in either subject. The disparity between LH and FSH secretion could be explained by the preferential inhibitory action of estrogen on FSH release, coupled with a relative insensitivity of FSH release. These data indicate that in these PCO patients the abnormalities of the hypothalamic-pituitary regulation of gonadotropin secretion was not an inherent defect but represented a functional derangement consequent to inappropriate estrogen feedback, which led to a vicious cycle of chronic anovulation and inappropriate gonadotropin secretion.

Rates of bone loss in the appendicular and axial skeletons of women. Evidence of substantial vertebral bone loss before menopause.

We made longitudinal measurements of bone mineral density (BMD) in 139 normal women (ages 20-88 yr) at midradius (99% cortical bone) and lumbar spine (approximately 70% trabecular bone) by single- and dual-photon absorptiometry. BMD was measured 2-6 (median, 3) times over an interval of 0.8-3.4 yr (median, 2.1 yr). For midradius, BMD did not change (+0.48%/yr, NS) before menopause but decreased (-1.01%/yr, P less than 0.001) after menopause. For lumbar spine, there was significant bone loss both before (-1.32%/yr, P less than 0.001) and after (-0.97%/yr, P = 0.006) menopause; these rates did not differ significantly from each other. Our data show that before menopause little, if any, bone is lost from the appendicular skeleton but substantial amounts are lost from the axial skeleton. Thus, factors in addition to estrogen deficiency must contribute to pathogenesis of involutional osteoporosis in women because about half of overall vertebral bone loss occurs premenopausally.

Higher maternal levels of free estradiol in first compared to second pregnancy: early gestational differences.

Serum samples drawn from 34 women in the early part of both their first and their second pregnancies were assayed for estradiol (E2), percentage of free E2, and sex hormone-binding globulin-binding capacity (SHBG-bc). Subjects were participants in the Collaborative Perinatal Study conducted by the National Institute of Neurological and Communicative Disorders and Stroke (Bethesda, MD) to evaluate factors related to adverse pregnancy outcome. All pregnancies were full term, and no offspring had a congenital malformation. After adjustment for week of pregnancy, the percentage of free E2 was 9% higher (two-sided P = .007) and the amount of free E2 was 17% higher (two-sided P = .03) in first-pregnancy sera. Total E2 was also 7% higher in first-pregnancy sera after adjustment for week of pregnancy; SHBG-bc was 7% lower after adjustment for week of pregnancy and 9% lower after simultaneous adjustment for week of pregnancy and weight at the start of pregnancy; but these differences were not statistically significant. These findings confirm our previously published hypothesis that the early part of a woman's first pregnancy differs endocrinologically from her second and may provide further insight into pregnancy-related risk factors for testis cancer and cryptorchidism and into the protection afforded by first full-term pregnancy against breast cancer.

Estrogen and sex hormone-binding globulin levels in nulliparous and parous women.

The hormone profiles of nulliparous and parous women on day 11 of their menstrual cycle have been studied in an attempt to seek evidence for the hormonal basis of the protective effect of first birth on breast cancer risk. A previous publication reported that there were significantly lower (26%) early morning prolactin levels in parous women as compared to those levels in nulliparous women but that there were no differences in plasma and urinary estrogen levels. The present study shows, however, that parous women had significantly shorter cycle lengths than nulliparous women of the same age, and the data were reevaluated with this difference being taken into account. After adjustment for cycle length (within the range of 24-32 days) and age, estrogen levels were significantly lower (22%) in parous women compared to those in nulliparous women. Two further aspects of estrogen metabolism were measured in the plasma samples of these women: the binding capacity of sex hormone-binding globulin (SHBG) and the percentage of free estradiol (E2). SHBG levels were 12% higher in parous women, but there was no difference in percentage of free E2. In the previous publication it was suggested that the protective effect of first birth on breast cancer risk was mediated in part by permanently lowering prolactin levels. The current findings suggest that changes in estrogen metabolism also are a factor.

Prediagnostic serum hormones and the risk of prostate cancer.

Serum samples were obtained from 6860 men during their study examination from 1971 to 1975. After a surveillance period of about 14 years, 98 incident cases of prostate cancer were identified. Their stored sera and that of 98 matched controls from the study population were tested for the following: testosterone, dihydrotestosterone, estrone, estradiol, and sex hormone globulin. There was a suggestion that serum dihydrotestosterone levels were lower and the testosterone/dihydrotestosterone ratios were higher in the prostate cancer cases compared with their controls. However, none of these associations or that of the other hormones was strongly significant. Further work is needed to clarify the relationship between sex hormones and prostate cancer risk.

In vivo effects of delta 1-testololactone on peripheral aromatization.

To evaluate the in vivo effect of delta 1-testololactone on peripheral aromatization, studies were performed on seven postmenopausal women with metastatic breast cancer. Analysis of variance indicated that there were significant increases of circulating androstenedione (p less than 0.05) and estradiol (p less than 0.001) during administration of different doses of testololactone. Androstenedione levels were increased with all doses of testololactone tested (50, 100, 250, and 500 mg every 6 hr for 14 days each), while estradiol rose with only the 250- and 500-mg dosages. With administration, there was a significant decrease of estrone (p less than 0.001) with the mean level falling from 26 +/- 3 (S.E.) to 11 +/- 2 pg/ml. The addition of adrenal suppression (dexamethasone, 1 mg nightly at 11 p.m.) significantly lowered androstenedione (p less than 0.05) but had no effect on estrone or estradiol levels. Long-term therapy (up to 6 months) with the 250-mg dosage showed continual suppression of estrone with no escape being observed. Studies to determine the reason for the increase of estradiol with testololactone suggested cross-reactivity of the antibody with in vivo metabolites of the drug. However, these possible metabolites did not bind to uterine cytosol estrogen receptors. The decrease in estrone with testololactone administration presumably explains its antitumor properties.

Effect of postmenopausal hormones on inflammation-sensitive proteins: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Study.

BACKGROUND: Observational studies in healthy women suggest postmenopausal hormone therapy reduces risk of coronary events. In contrast, in a recent clinical trial of women with coronary disease, a subgroup analysis demonstrated increased risk during the early months of therapy. Because higher levels of inflammation factors predict vascular disease outcomes, the effect of hormones on these factors is of interest. METHODS AND RESULTS: Four inflammation-sensitive factors, C-reactive protein, soluble E-selectin, von Willebrand factor antigen, and coagulation factor VIIIc were measured at baseline, 12, and 36 months in 365 participants of the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial, a randomized, placebo-controlled trial of the effects of 4 hormone preparations on cardiovascular disease risk factors. Compared with placebo, all 4 active preparations resulted in a large sustained increase in the concentration of C-reactive protein and a decrease in soluble E-selectin (P=0.0001). There were no effects of treatment on concentrations of von Willebrand factor or factor VIIIc. There were no differences in effects among treatment arms. Relative to placebo, when combining active treatment arms, final concentrations of C-reactive protein were 85% higher whereas E-selectin was 18% lower compared with baseline. CONCLUSIONS: Postmenopausal hormones rapidly increased the concentration of the inflammation factor C-reactive protein. Such an effect may be related to adverse early effects of estrogen therapy. In contrast, hormones reduced the concentration of soluble E-selectin, and this might be considered an anti-inflammatory effect. Because PEPI was not designed to assess clinical endpoints, studies of the impact of hormone-mediated changes in inflammation on risk of subsequent coronary events are needed.

Is caffeine consumption a risk factor for osteoporosis?

High caffeine consumption has been proposed as a risk factor for osteoporotic fracture, but the evidence associating high caffeine intake with low bone density is inconsistent. We therefore examined the influence of caffeine consumption on bone mineral at six skeletal sites in an age-stratified random sample of white women residing in Rochester, Minnesota. After age adjustment, there was no association between overall caffeine consumption and bone mineral at five of the six sites. In the femoral shaft, however, there was a statistically significant interaction between age and caffeine consumption so that high caffeine intake was associated with slight reductions in bone mineral among elderly subjects but with modestly increased bone mineral at younger ages. When caffeine intake was categorized by source, no consistent influence of coffee, tea, or other caffeinated beverage consumption could be detected on bone mineral. Caffeine intake was, however, positively associated with cigarette smoking and alcohol consumption. After adjusting for age, caffeine consumption was not correlated with biochemical indices of bone turnover, circulating concentrations of estradiol and estrone, or other dietary and musculoskeletal variables. These data suggest that caffeine intake in the range consumed by a representative sample of white women is not an important risk factor for osteoporosis. Among elderly women, however, in whom calcium balance performance is impaired, high caffeine intake may predispose to cortical bone loss from the proximal femur.

Relation of circulating estradiol and progesterone to gonadotropin secretion and estrous cyclicity in aging female rats.

The progressive cessation of regular ovulatory function in aging female rats is preceded by a significant decrease in the magnitude of the proestrous LH surge during regular estrous cycles. However, our recent study has demonstrated that normal LH secretion and regular estrous cycles can be maintained for an extended period of time in aging females housed with fertile males and allowed to undergo repeated pregnancies. Since progesterone (P) secretion is persistently increased in pregnant rats, the present study examined whether repeated increases in circulating progesterone accounted for these results. Starting at 8 months of age and continuing to 13 months, multiparous rats were grouped and treated as follows: controls: females were housed five per cage; mated: five females were housed with one fertile male and allowed to undergo repeated pregnancies; and P-implanted: females were housed five per cage and implanted sc with Silastic capsules containing P for 3 of every 4 weeks. During the 4.5 months of study, serum concentrations of estradiol (E2) in the P-implanted rats remained between 13 and 27 pg/ml, similar to levels in pregnant females (8-26 pg/ml) of the mated group. These E2 values were less than the preovulatory increase in serum E2 on proestrus (mean +/- SE, 56 +/- 10 pg/ml) in cyclic control females. In contrast, serum P values were persistently elevated in both the pregnant and the P-implanted rats, although the values in the latter (27-55 ng/ml) were about one third to one half of those in the former group (117-125 ng/ ml). All treatments were stopped at 13 months of age, and estrous cycle patterns were determined thereafter. Between 13 and 17 months of age, the percentages of regularly cycling rats were significantly (P less than 0.01) greater in the mated group (50%, 36%, and 15% at 13, 15, and 17 months, respectively) than in the control group (23%, 20%, and 9%, respectively). During this same period, 50% of the females from the P-implanted group continued to display regular cycles. By the age of 11 months, 8 of 21 untreated retired breeder females exhibited attenuated LH surges on proestrus and subsequently ceased to display regular estrous cycles within 2 months, whereas the other 13 rats showed normal LH and FSH surges and continued to maintain regular cycles. In contrast to these, aged female rats from the previously mated (15-month-old) and the P-implanted (19-month-old) groups exhibited normal profiles of proestrous LH and FSH surges during regular estrous cycles.(ABSTRACT TRUNCATED AT 400 WORDS)

Reduction of vasomotor symptoms and bone mineral density loss with combined norethindrone and long-acting gonadotropin-releasing hormone agonist therapy of symptomatic endometriosis: a prospective randomized trial.

The hypoestrogenic state induced by gonadotropin-releasing hormone agonists (GnRHa) has been shown to suppress symptomatic endometriosis effectively but to elicit vasomotor symptoms and loss of bone mineral density. The role of norethindrone as a supplement to GnRHa in eliminating such side effects was assessed by enrolling 20 patients with symptomatic endometriosis diagnosed laparoscopically in a randomized, prospective, double-blinded trial. All patients received the long-acting GnRHa leuprolide acetate 3.75 mg im every 4 weeks for 24 weeks. Ten patients self-administered norethindrone 5 then 10 mg by mouth daily, whereas the remainder self-administered placebo tablets. Results of this study showed that combination therapy was as effective as GnRHa alone in significantly reducing circulating gonadotropin and estrogen levels (P less than 0.01), extent of visible endometriotic implants (P less than 0.01), and painful symptoms (P less than 0.01). Marked vasomotor and vaginal symptoms experienced by patients given GnRHa alone were minimized in those receiving GnRHa with norethindrone. Lumbar spine bone mineral density loss, measured by dual energy x-ray absorptiometry, was significantly reduced and more completely reversed in patients receiving combination therapy (P less than 0.05). A reversible decrease in high density lipoprotein-cholesterol and increase in low density lipoprotein:high density lipoprotein ratio was noted only in the patients receiving combination therapy, but not in those receiving GnRHa only. The addition of norethindrone to GnRHa is an effective means of treating symptomatic endometriosis while ameliorating side effects induced by GnRHa alone.

Effects of human cirrhotic serum on estradiol and testosterone transport into rat brain.

It is known that sex hormone-binding globulin (SHBG), which binds both testosterone and estradiol in human serum, is markedly elevated in cirrhosis. In addition, it is known that the net metabolic clearance of testosterone is decreased in cirrhosis, while no change in the metabolic clearance of estradiol is observed. Since net clearance estimates are not direct measures of plasma protein binding effects, the present studies were designed to examine the effects of cirrhotic human serum on the unidirectional clearance of sex steroids using an in vivo rat brain paradigm previously described. Cirrhotic serum was characterized by the following changes from control serum: 2.6-fold increase in SHBG, 40% decrease in albumin, and 30% and 22% decreases in the dialyzable fractions of testosterone and estradiol, respectively. In addition, the non-SHBG-bound fraction of estradiol was decreased 41% in cirrhosis, but no significant change in the brain extraction of estradiol was observed using cirrhotic serum. In contrast, the unidirectional testosterone clearance was decreased 33% by cirrhotic serum. These studies indicate that changes in the net metabolic clearance of sex steroids closely parallel the changes in unidirectional clearance caused by alterations in plasma proteins. The absence of a decrease in estradiol clearance in cirrhosis in association with the substantial decrease in the non-SHBG-bound estradiol fraction is an unexpected finding, since previous studies have shown that a close parallel exists between these two parameters. A possible explanation is that estradiol bound to the SHBG in human cirrhotic serum is partially available for transport into peripheral tissues such as the brain.

Protein-bound corticosteroid in human serum is selectively transported into rat brain and liver in vivo.

It is generally regarded that only free corticosteroid is available for entry into tissues in vivo, although some studies have suggested that albumin-bound corticosteroid is available for liver uptake. However, recent studies suggest that owing to favorable kinetic relationships among tissue capillary transit times and hormone dissociation rates from plasma proteins, free plus albumin-bound hormone may be available to peripheral tissues. Moreover, globulin-bound hormone may enter the liver under normal conditions and be available to peripheral tissues under pathological circumstances. The present studies measure the free and noncorticosteroid-binding globulin (non-CBG)-bound corticosteroid fractions in vitro and compare these measurements to the fraction of corticosteroid in human sera that is available for entry into rat brain and rat liver in vivo. Corticosterone was used as the model corticosteroid, since this compound binds to CBG with the same affinity as does cortisol, and the brain extraction of corticosterone is more readily measured in vivo than is the brain extraction of cortisol. Serum was obtained from 51 human subjects and included samples from newborns, pregnant mothers, normal subjects, and patients with either cirrhosis or renal failure. Serum levels of CBG varied more than 6-fold, and both the free and the non-CBG-bound fractions were generally inversely related to the CBG concentration. The fraction of corticosterone available for entry into the brain was much greater than the free fraction, but was not significantly different from the non-CBG-bound moiety. Moreover, the rate of corticosterone dissociation from CBG (t 1/2 = 27 +/- 1 sec at 22 C) was not increased in any of the serum samples studied. The fraction of corticosterone available for uptake by the liver was up to 3-fold greater than that of the non-CBG fraction and had no relationship with the serum concentration of CBG. These studies indicate that albumin-bound, but not globulin-bound, corticosteroid is available for entry into a peripheral tissue such as the brain. However, globulin-bound corticosteroid is readily transported into the liver. It is suggested that the routine measurements of the non-CBG-bound corticosteroid provide a more accurate index of the corticosteroid available to peripheral tissues in vivo than does the measurement of free corticosteroid.

Objectively recorded hot flushes in patients with pituitary insufficiency.

A study was conducted of 2 young adult women with pituitary insufficiency and complaints of hot flushes. Both underwent continuous recordings of skin temperature of the finger and skin resistance over the sternum as objective indices of flushing episodes. Frequent blood samples were also obtained during the recordings for the measurement of serum LH and FSH levels. During the 10 h of recording, 12 subjective hot flushes occurred and each was associated with a rise of finger temperature of greater than 1 C. Eighty-five percent of the temperature rises were associated with measurable decreases in skin resistance. The mean interval between flushes, the magnitude of the skin temperature and resistance changes, and the relationship of these changes to the onset of subjective flushes were identical to those observed in symptomatic postmenopausal women. Circulating gonadotropin levels were in the low to low normal range in comparison to values observed in premenopausal women and showed minimal pulsatile release. There were no significant correlations between finger temperature changes and LH levels in either subject. These results suggest that the previously described association of pulsatile LH release and the occurrence of hot flushes in postmenopausal women cannot be attributed to augmented LH secretion per se and, therefore, may be due to hypothalamic factors responsible for pulsatile LH release.

Sleep-wake patterns of LH and testosterone release in prepubertal boys.

Ten prepubertal boys who ranged in age from 6 11/12 to 14 2/12 years were studied for 2 consecutive nights. The subjects went to sleep at their usual times and sleep patterns were monitered polygraphically. Each night blood samples were drawn every 30 min from 1800 to 0600 h and plasma LH and testosterone (T) levels were measured on each sample. During evening wakefulness the mean LH (range 2.8-5.1 mIU/ml) and T (range 31-116 pg/ml) levels were in the normal prepubertal range for each subject. In the 5 youngest subjects (age 6 11/12 to 10 8/12 years) the mean hormone levels during sleep were significantly higher than the wakeful levels in 2 of 9 and 0 of 9 study nights for LH and T, respectively. In contrast, in the older prepubertal boys (age 13 2/12 to 14 2/12 years) the mean levels during sleep were significantly higher than wakeful values during 8 of 9 and 5 of 9 study nights for the same respective hormones. These data suggest that in young prepubertal subjects the sleep related rises of LH and T are either absent or not discernible in the peripheral blood. The prepubertal pattern of sleep-entrained LH and T release may be seen in prepubertal boys approaching the time of puberty and these hormonal rhythms are antecedent to the physical changes of puberty.

Differential permeability of uterine and liver vascular beds to estrogens and estrogen conjugates.

The role of capillary membrane permeability and the effect of plasma protein binding on the influx of unconjugated and conjugated estrogens into a target organ, the uterus, and a metabolic organ, the liver, were studied in anesthetized rats. In the absence of plasma proteins, estrone (E1) and estradiol (E2) were freely diffusible through the uterine capillaries, but influx was significantly reduced for estriol (E3) and estetrol. In the uterus, the influx of the conjugated estrogens was markedly restricted and approximated the influx of dextran, a vascular space marker. The polarity of the compound (based on the number of hydrogen bond-forming functional groups and the presence of charged groups) appeared to predict uterine endothelial membrane permeability better than the octanol/Ringer's partition coefficient. In contrast to the selective permeability properties of the uterine endothelial barrier, the limiting membrane lining the hepatic microcirculation, the hepatocyte cell membrane, was highly permeable to all unconjugated and conjugated estrogens. The addition of 4% albumin to the injection solution led to a significant inhibition of uterine influx of E2, but not E1 or E3. In the liver, only the influx of E1 sulfate was slightly diminished by 4% albumin. In all cases, the influx of estrogens greatly exceeded the rate that would be expected if only the fraction that was free (dialyzable) in vitro was diffusible in vivo. Human sera containing sex hormone-binding globulin and albumin caused inhibition of influx of E1 and E2 through the uterine capillary barriers, whereas in the liver, the influx of E2 sulfate, and E3 glucuronide were diminished. The results are compatible with a difference in permeability of the microvasculature of the two organs and a differential availability of protein-bound estrogen for influx into liver and uterus. With the exception of E1, which is nearly completely diffusible into both organs, the influx of estrogens and estrogen conjugates into liver is greatly amplified compared to that into a peripheral organ such as the uterus.

Serum bioavailability and tissue metabolism of testosterone and estradiol in rat salivary gland.

The concentration of testosterone in saliva is probably in equilibrium with the concentration of cellular exchangeable testosterone in salivary gland, and these pools are a function of hormone transplant from the plasma compartment, and hormone metabolism in salivary gland cells. Both of these processes were examined in the present study using the carotid injection technique in normal and pilocarpine-stimulated ketamine-anesthetized rats. Both testosterone and estradiol were rapidly transported across salivary gland capillaries in vivo from the circulating albumin-bound pool. Estradiol, but not testosterone, was also rapidly transported into salivary gland from the circulating human sex hormone-binding globulin-bound pool. Hormone transport was several-fold greater than the capillary transport of [3H]bovine albumin, indicating that bound hormone was available for transport across salivary gland capillaries via an enhanced dissociation mechanism, with the plasma protein primarily residing in the plasma compartment. This result was confirmed by thaw-mount autoradiography, which showed diffuse distribution of [3H]testosterone in salivary gland, but vascular retention of [3H]bovine albumin. The concentration of exchangeable cellular testosterone in rat saliva was less than 4% of the total or plasma exchangeable testosterone in the rat. This marked discrepancy between the concentration of plasma and cellular exchangeable hormone suggested that there was rapid metabolism of androgen by salivary gland in vivo. This was confirmed by chromatographic separation of [3H] testosterone and labeled metabolites in homogenates of salivary gland. By 60 sec after injection, approximately 30% of the radioactivity in the salivary gland was in the form of androgen metabolites, which primarily comigrated with an androstenedione standard. The data indicate that albumin-bound testosterone, albumin-bound estradiol, and sex hormone-binding globulin-bound estradiol are all exchangeable in salivary gland capillaries. The low concentration of cellular exchangeable testosterone in salivary gland appears to be due to rapid tissue metabolism of this hormone. Thus, changes in androgen metabolism may alter salivary gland hormone concentrations independent of any change in the concentration of biologically active hormone in plasma.

A mechanism for the suppression of estrogen production in polycystic ovary syndrome.

In polycystic ovary syndrome (PCOS), follicle development arrests in the early antral stage when aromatase expression in the granulosa cells (GC) would normally occur. Despite high intrafollicular concentrations of androstenedione and bioactive FSH, in vivo estrogen biosynthesis remains low. When GC from PCOS follicles are stimulated with FSH in vitro, a marked stimulation of estrogen production occurs, suggesting that PCOS follicles contain an endogenous inhibitor of estrogen production. To test this hypothesis, GC from hyperstimulated women were cultured with increasing concentrations of follicular fluid (FF) from PCOS and normally cycling control women in the presence of androstenedione (10(-5) mol/L). FF from control women caused a small decrease (20%) in estradiol production. PCOS FF caused a dose-related inhibition of estradiol production (60%), indicating that there was significantly more inhibitory activity in PCOS FF. To determine whether abnormal androgen metabolism could play a role in inhibiting estradiol production in PCOS, we measured 5 alpha-androstane-3, 17-dione, a competitive inhibitor of aromatase activity, in serum and FF of control and PCOS women. 5 alpha-Androstane-3, 17-dione levels in serum were significantly elevated in PCOS. 5 alpha-Androstane-3, 17-dione levels were 1000-fold higher in PCOS FF than serum. Moreover, FF levels were markedly higher in PCOS follicles (P < 0.0001) than in normal dominant and cohort follicles. Dose-response studies revealed that the concentration of 5 alpha-androstane-3, 17-dione present in FF form normal dominant follicles (79.4 +/- 14.6 nmol/L) had little effect on estradiol production. In contrast, 5 alpha-androstane-3, 17-dione levels in PCOS FF (581.6 +/- 62.9 nmol/L) inhibited estradiol production by 75%. These data support the hypothesis that PCOS FF contains one or more endogenous inhibitors of aromatase activity and suggest that abnormally high 5 alpha-androstane-3, 17-dione levels in PCOS FF may be an important inhibitor of estradiol production.

Serum 17 beta-estradiol and estrone levels in postmenopausal women with and without endometrial cancer.

Serum 17 beta-estradiol (E2) and estrone (E1) levels were measured before and 6-8 weeks after ovariectomy in 16 postmenopausal women with endometrial cancer, and in 10 postmenopausal women with normal endometrium (preovariectomy only). For E2, no significant difference in the mean baseline (+/-SE) level was found between the tumor (13.5 +/- 1.1 pg/ml) and non-tumor patients (11.7 +/- 1.4 pg/ml). For the same patients, the mean baseline E1 levels of 33.8 +/- 2.4 pg/ml and 28.5 +/- 4.7 pg/ml were also not significantly different. The mean body weight of the tumor patients (141.1 +/- 7.3 lbs.) was similar to the mean weight of the non-tumor subjects (137.5 +/- 6.3 lbs.). This was of importance since both E2 and E1 levels correlated significantly with body weight and excess fat in these postmenopausal women. The circulating estrogen levels did not correlate significantly with the patients' height, age, or years of menopause. In the patients with endometrial cancer the mean E2 (14.1 +/- 1.7 pg/ml) and E1 (39.5 +/- 7.3 pg/ml) levels after ovariectomy were not significantly different from the preoperative concentrations. These data are consistent with the concept that in postmenopausal women most, if not all, circulating estrogen is produced by peripheral conversion of androgens and that this conversion is influenced by obesity. Circulating estrogen levels are not significantly different in postmenopausal patients with endometrial cancer compared with women of a similar age and weight who do not have the tumor.

The effects of naloxone on hot flashes and gonadotropin secretion in postmenopausal women.

Hot flashes have a close temporal relationship with the initiation of LH pulses, suggesting that factors stimulating gonadotropin release are involved in the mechanism of this disturbance. It has been reported that the opiate antagonist naloxone acutely blocked subjective hot flashes, a seemingly paradoxical effect, since the use of this agent in premenopausal women increases the magnitude and frequency of LH pulses. We, therefore, studied the effects of naloxone in 16 postmenopausal women with frequent hot flashes using continuous recordings of finger temperature and skin resistance as objective indices of flushing and perspiration, respectively. After baseline recordings, the subjects were randomized into equal groups, and the recordings were repeated during 8-h infusion of either saline or naloxone (22 micrograms/min). Serum gonadotropin levels were measured at 15-min intervals before and during the last 4 h of the infusion. Naloxone did not change the rate of objectively measured hot flashes, mean serum LH or FSH levels, or the frequencies or amplitudes of gonadotropin pulses. These data suggest that there is a very low input of endogenous opiates on gonadotropin secretion in postmenopausal women and that opioid peptides do not play a role in the initiation of the postmenopausal hot flash.