The metabolic clearance rates of dehydroepiandrosterone, testosterone and their sulphate esters in man, rat and rabbit

Fasting increases aggression and differentially modulates local and systemic steroid levels in male zebra finches

Aggression enables individuals to obtain and retain limited resources. Studies of the neuroendocrine regulation of aggression have focused on territorial and reproductive contexts. By contrast, little is understood concerning the neuroendocrine regulation of aggression over other resources, such as food. Here, we developed a paradigm to examine the role of steroids in food-related aggression. In groups of male zebra finches, a 6-hour fast decreased body mass and increased aggressive interactions among subjects that competed for a point source feeder. Fasting also dramatically altered circulating steroid levels by decreasing plasma testosterone but not estradiol (E2). By contrast, both plasma corticosterone and dehydroepiandrosterone (DHEA) concentrations were elevated with fasting. Interestingly, short-term access to food (15 minutes) after fasting normalized circulating steroid levels. Fasting increased corticosterone levels in a wide range of peripheral tissues but increased DHEA levels specifically in adrenal glands and liver; these effects were quickly normalized with refeeding. DHEA can be metabolized within specific brain regions to testosterone and E2, which promote the expression of aggression. We measured E2 in microdissected brain regions and found that fasting specifically increased local E2 levels in 3 regions: the periaqueductal gray, ventral tegmental area, and ventromedial nucleus of the hypothalamus. These regions are part of the vertebrate social behavior network and regulate the expression of aggression. Together, these data suggest that fasting stimulates secretion of DHEA from the adrenals and liver and subsequent conversion of DHEA to E2 within specific brain regions, to enable individuals to compete for limited food resources.

The Androgen Excess and PCOS Society criteria for the polycystic ovary syndrome: the complete task force report

OBJECTIVE

To review all available data and recommend a definition for polycystic ovary syndrome (PCOS) based on published peer-reviewed data, whether already in use or not, to guide clinical diagnosis and future research.

DESIGN

Literature review and expert consensus.

SETTING

Professional society.

PATIENTS

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A systematic review of the published peer-reviewed medical literature, by querying MEDLINE databases, to identify studies evaluating the epidemiology or phenotypic aspects of PCOS.

RESULT(S)

The Task Force drafted the initial report, following a consensus process via electronic communication, which was then reviewed and critiqued by the Androgen Excess and PCOS (AE-PCOS) Society AE-PCOS Board of Directors. No section was finalized until all members were satisfied with the contents, and minority opinions noted. Statements were not included that were not supported by peer-reviewed evidence.

CONCLUSION(S)

Based on the available data, it is the view of the AE-PCOS Society Task Force that PCOS should be defined by the presence of hyperandrogenism (clinical and/or biochemical), ovarian dysfunction (oligo-anovulation and/or polycystic ovaries), and the exclusion of related disorders. However, a minority considered the possibility that there may be forms of PCOS without overt evidence of hyperandrogenism, but recognized that more data are required before validating this supposition. Finally, the Task Force recognized and fully expects that the definition of this syndrome will evolve over time to incorporate new research findings.

Heritability of dehydroepiandrosterone sulfate in women with polycystic ovary syndrome and their sisters

OBJECTIVE

To test the hypothesis that adrenal androgen (AA) secretion is an inherited trait in PCOS and that serum DHEAS concentrations, as a marker of AA secretion, will be correlated between women with PCOS and their sisters.

DESIGN

Prospective case-control.

SETTING

Tertiary care center.

PATIENT(S)

Sixty-two PCOS probands and 69 sisters.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The DHEAS concentrations and clinical phenotypes were obtained. Familial correlation between sisters was estimated. A variance components model was used to estimate the heritability (h(2)) of the DHEAS levels. Body mass index (BMI)-adjusted DHEAS levels were used in all of the analyses.

RESULT(S)

There was no difference in age between the proband and sister groups (28.7 +/- 8.1 years vs. 28.0 +/- 8.8 years, P=.65), and probands had higher BMI values (33.4 +/- 7.6 kg/m(2) vs. 27.9 +/- 7.0 kg/m(2), P<.001). Sixteen of the 69 (23.2%) sisters were affected by PCOS. The sister-sister correlation of DHEAS level was 0.28 +/- 0.12 for the whole group (P<.05), and this correlation was higher, at 0.38 +/- 0.14 (P< or =.05), after excluding 31% of the affected sisters and 34% of the unaffected sisters who received hormonal therapy at or within 3 months of the time of the study. The h(2) estimates of DHEAS were 0.43 (P=.037) and 0.44 (P=.062) when all sisters and only untreated sisters, respectively, were included in the analysis.

CONCLUSION(S)

The correlation of serum DHEAS levels between PCOS probands and their sisters suggests a familial component in the regulation of DHEAS levels and possibly AA production in PCOS. The h(2) estimates of 0.43-0.44 for BMI-adjusted DHEAS suggest that genetic factors account for between 40% and 50% of the overall variation in DHEAS levels in these women. Our results support the hypothesis that circulating AA levels represent an inherited trait in PCOS.

Dehydroepiandrosterone secretion in healthy older men and women: effects of testosterone and growth hormone administration in older men

CONTEXT

Aging is associated with diminished gonadal steroid and GH/IGF-I axis activity; whether these changes contribute to the parallel declines of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) production is unknown, as are the effects of sex steroid and/or GH administration on DHEA and DHEAS production.

OBJECTIVE

Our objective was to evaluate morning DHEAS concentrations and nocturnal DHEA secretory dynamics in healthy older men and women, before and after chronic administration of sex steroid(s) alone, GH alone, sex steroid(s) combined with GH, or placebo alone.

DESIGN

We compared nocturnal DHEA secretory dynamics (2000 h to 0800 h, sampling every 20 min, analyzed by multiparameter deconvolution and approximate entropy algorithms) in healthy older (65-88 yr) men (n = 68) and women (n = 36), both before and after 26 wk of administration of sex steroid(s) alone [testosterone (T) in men or estrogen/progesterone in women], GH alone, sex steroid(s) combined with GH, or placebo alone.

RESULTS

Morning concentrations of DHEAS were lower; nocturnal DHEA pulsatile production rate, burst frequency, and amplitude were higher; and half-life was shorter in women (P < 0.05). Nocturnal integrated DHEA concentrations, total production rate, and approximate entropy did not differ significantly by sex. Because of small treatment group sizes in women, only hormone intervention results in men are presented. In men, T and T plus GH administration significantly decreased nocturnal integrated DHEA but not morning DHEAS concentrations. GH alone exerted no significant effects on nocturnal DHEA secretion or morning DHEAS.

CONCLUSIONS

Spontaneous nocturnal DHEA secretion is sexually dimorphic in healthy older individuals, and T administration decreases nocturnal DHEA secretion in older men. The clinical significance of sex steroid modulation of DHEA secretion in older persons remains to be elucidated.

The decline of androgen levels in elderly men and its clinical and therapeutic implications

Aging in men is accompanied by a progressive, but individually variable decline of serum testosterone production, more than 20% of healthy men over 60 yr of age presenting with serum levels below the range for young men. Albeit the clinical picture of aging in men is reminiscent of that of hypogonadism in young men and decreased testosterone production appears to play a role in part of these clinical changes in at least some elderly men, the clinical relevancy of the age-related decline in sex steroid levels in men has not been unequivocally established. In fact, minimal androgen requirements for elderly men remain poorly defined and are likely to vary between individuals. Consequently, borderline androgen deficiency cannot be reliably diagnosed in the elderly, and strict differentiation between "substitutive" and "pharmacological" androgen administration is not possible. To date, only a few hundred elderly men have received androgen therapy in the setting of a randomized, controlled study, and many of these men were not androgen deficient. Most consistent effects of treatment have been on body composition, but to date there is no evidence-based documentation of clinical benefits of androgen administration to elderly men with normal or moderately low serum testosterone in terms of diminished morbidity or of improved survival or quality of life. Until the long-term risk-benefit ratio for androgen administration to elderly is established in adequately powered trials of longer duration, androgen administration to elderly men should be reserved for the minority of elderly men who have both clear clinical symptoms of hypogonadism and frankly low serum testosterone levels.

The Use of Dehydroepiandrosterone Therapy in Clinical Practice

Dehydroepiandrosterone (DHEA) therapy is controversial due to sensationalized reports of epidemiologic studies and the over-the-counter availability of DHEA. Human clinical trials have investigated the potential efficacy of DHEA therapy in multiple conditions with resultant inconsistencies in findings. DHEA is unique compared with other adrenal steroids because of the fluctuation in serum levels found from birth into advancing age. The lower endogenous levels of DHEA and DHEA sulfate found in advancing age have been correlated with a myriad of health conditions. Also, some studies suggest gender-specific actions of endogenous and exogenous DHEA. We reviewed only pharmacokinetic studies and human clinical trials investigating the efficacy of DHEA therapy that were placebo-controlled as these provided the most reliable scientific basis for the evaluation of DHEA therapy. Pharmacodynamic studies suggest that doses of 30-50mg of oral DHEA may produce physiologic androgen levels, especially in women. These studies report a dose-dependent effect and lack of accumulation of serum androgen levels. Pharmacologic studies also reveal a gender-specific response to DHEA therapy such that testosterone levels are increased in women but not in men. Clinical trials suggest that 50mg of oral DHEA, but not <30mg, can increase serum androgen levels to within the physiologic range for young adults with primary and secondary adrenal insufficiency, possibly improve sexual function, improve mood and self-esteem, and decrease fatigue/exhaustion. Whereas DHEA replacement therapy may be effective in treating patients with adrenal insufficiency, human clinical trials investigating its efficacy in conditions such as systemic lupus erythematosus, HIV, Alzheimer disease, advancing age, male sexual dysfunction, perimenopausal symptoms, depression, and cardiovascular disease have not provided consistent findings.

Oral testosterone-triglyceride conjugate in rabbits: single-dose pharmacokinetics and comparison with oral testosterone undecanoate

Development of a safe and effective oral form of testosterone has been inhibited by the rapid hepatic metabolism of nonalkylated androgens. Since triglycerides are absorbed via lymphatics and bypass the liver, we hypothesized that a testosterone-triglyceride conjugate (TTC) might allow for safe and effective oral testosterone therapy. Therefore, we studied the single-dose pharmacokinetics of oral administration of TTC in rabbits. Female New Zealand rabbits were administered 2, 4, or 8 mg/kg of TTC in sesame oil by gastric lavage. Testosterone undecanoate (TU) by gastric lavage was used as a positive control. Blood was sampled from a catheter in the auricular artery at 0, 15, 30, 60, 90, 120, 180, 240, 360, 480, and 600 minutes after drug administration. Samples were assayed for testosterone by a fluoroimmunoassay. Mean serum testosterone, area under the curve (AUC), and terminal half-life were calculated. Oral TTC administration resulted in rapid and marked increases in serum testosterone. Oral TTC resulted in higher maximum serum testosterone concentrations than oral TU at 8 mg/kg (TTC: 28.6 +/- 7.9 nmol/L vs TU: 11.9 +/- 2.1 nmol/L; P <.001) and 4 mg/kg (TTC: 11.5 +/- 4.2 nmol/L vs TU: 3.6 +/- 1.0 nmol/L; P <.001). In addition, the AUC was 1.8 to 2.6 times greater for TTC than TU at both doses (P <.05). The terminal half-life for both TU and TTC was between 3 and 5 hours and was not significantly different. We conclude that oral TTC is rapidly absorbed from the rabbit intestine and results in elevated concentrations of serum testosterone. The absorption of TTC appears to be superior to that of TU; however, the in vivo persistence of the 2 compounds is similar. TTC may offer an alternative to the use of TU for oral testosterone therapy. Further testing of this compound is warranted.

Cholesterol sulfate in human physiology: what's it all about?

Cholesterol sulfate is quantitatively the most important known sterol sulfate in human plasma, where it is present in a concentration that overlaps that of the other abundant circulating steroid sulfate, dehydroepiandrosterone (DHEA) sulfate. Although these sulfolipids have similar production and metabolic clearance rates, they arise from distinct sources and are metabolized by different pathways. While the function of DHEA sulfate remains an enigma, cholesterol sulfate has emerged as an important regulatory molecule. Cholesterol sulfate is a component of cell membranes where it has a stabilizing role, e.g., protecting erythrocytes from osmotic lysis and regulating sperm capacitation. It is present in platelet membranes where it supports platelet adhesion. Cholesterol sulfate can regulate the activity of serine proteases, e.g., those involved in blood clotting, fibrinolysis, and epidermal cell adhesion. As a result of its ability to regulate the activity of selective protein kinase C isoforms and modulate the specificity of phosphatidylinositol 3-kinase, cholesterol sulfate is involved in signal transduction. Cholesterol sulfate functions in keratinocyte differentiation, inducing genes that encode for key components involved in development of the barrier. The accumulating evidence demonstrating a regulatory function for cholesterol sulfate appears solid; the challenge now is to work out the molecular mechanisms whereby this interesting molecule carries out its various roles.

Effects of oral prasterone (dehydroepiandrosterone) on single-dose pharmacokinetics of oral prednisone and cortisol suppression in normal women

This study sought to determine effects of multiple dosing of prasterone (DHEA, dehydroepiandrosterone) on the pharmacokinetics of prednisolone and endogenous cortisol secretion. These drugs are likely to be coadministered to patients with systemic lupus erythematosus. Fourteen normal women (ages 30.1 +/- 5.4 years) received single-dose oral prednisone (20 mg) before and after 200 mg/day of oral prasterone for one menstrual cycle (approximately 28 days). Identical assessments, timed to onset of menses, were conducted pretreatment (baseline) and at days 28 and 29 of prasterone treatment and included serum total and free prednisolone, prednisone, DHEA, DHEA-S (dehydroepiandrosterone sulfate), ACTH-stimulated cortisol, and sex hormones and 24-hour urine free cortisol. Pharmacokinetic parameters of prednisolone as assessed by Cmax, t 1/2, AUC, or serum protein binding were not affected by prasterone. The ACTH-stimulated plasma cortisol concentrations were mildly reduced, but 24-hour urinefree cortisol excretion was unchanged during prasterone administration. Serum androstenedione and testosterone increased, while no changes in serum estradiol or estrone occurred. The administration of 200 mg oral prasterone produced serum concentrations of DHEA and DHEA-S significantly greater than endogenous levels. Chronic dosing with 200 mg/day of prasterone did not alter either prednisolone pharmacokinetics or inhibition of cortisol secretion by prednisolone.

Metabolic conversion as a pre-receptor control mechanism for lipophilic hormones

The majority of physiological effects mediated by steroids, retinoids and thyroids is accomplished by binding to members of the nuclear receptor superfamily of ligand activated transcription factors. The complex specific effects of lipid hormones depend not only on receptor expression, distribution and interactions, but also on the availability and metabolic conversion of the hormone itself. The cell-specific metabolic activation of inactive hormone precursors introduces a further level of hormonal regulation, and constitutes an important concept in endocrinology. The metabolic reactions carried out are achieved by dehydrogenases/reductases, hydroxylases and other enzymes, acting on ligands of the steroid/thyroid/retinoic hormone receptor superfamily. The concept implies that these tissue- and cell-specific metabolic conversions contribute to lipid hormone action, thus pointing to novel targets in drug development. All components of this signalling system, the hormone compounds, the receptor proteins, and modifying enzyme families originate from an early metazoan date, emphasizing the essential nature of all elements for development and diversification of vertebrate life.

Re-examination of the effect of hCG on plasma levels and renal excretion of dehydroepiandrosterone sulfate in healthy males

To reinvestigate the effect of hCG on circulating and urinary dehydroepiandrosterone sulfate (DHEAS), a hCG stimulation test (5000 IU administered i.m. at 8.30 h on 3 consecutive days) was performed in 6 healthy males (aged 24 to 35 years). Blood specimens and 24-h urine samples were collected immediately before the first and directly after the last hCG administration. Contrary to previous findings in normal men, the present study revealed significant DHEAS responses after testicular stimulation with hCG: plasma DHEAS increased from 7.9 +/- 2.3 to 9.6 +/- 2.2 mumol/L (P < 0.05) and urinary DHEAS from 5.7 +/- 3.6 to 9.3 +/- 5.2 mumol/day (P < 0.05). There was also a marked rise (P < 0.05) in the urinary excretion of total 17-ketosteroid sulfates. Clear increases of unconjugated plasma dehydroepiandrosterone as well as of circulating and renally excreted androstenedione and testosterone definitely confirmed an adequate Leydig cell stimulation. Significant post-hCG changes were additionally observed for plasma and urinary 3 alpha-androstanediol glucuronide (149% and 79% increases, respectively) and for urinary cortisol (21% decrease). Significant correlations were found for the post-hCG percent increases of plasma androstenedione versus plasma DHEAS (r = 0.86) and for the percent increases of plasma testosterone versus urinary DHEAS (r = 0.98), indicating that the extent of gonadal androgen elevations in the circulation of normal men is a determinant of DHEAS increases in blood or urine. These findings provide an explanation for the frequently observed sex differences for DHEAS in adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum dehydroepiandrosterone sulfate in Alzheimer's disease and in multi-infarct dementia

Circulating levels of dehydroepiandrosterone sulfate (DHEAS) and cortisol were studied in 86 patients with dementia; 45 with Alzheimer's disease and 41 with multi-infarct dementia. Compared to an elderly control group, after adjustment for age and sex, patients with Alzheimer's disease were found to have lower serum levels of DHEAS. We found a covariation between serum albumin and DHEAS levels, which may be of importance regarding peripheral hormone concentration in patients with dementia. These findings may provide evidence for a role of DHEAS in amnestic disorder in humans, either reflecting or contributing to the course of dementing diseases.

Radioimmunoassay of 7 alpha-methyl-19-nortestosterone and investigation of its pharmacokinetics in animals

A method for the measurement of 7 alpha-methyl-19-nortestosterone (7MENT) in serum/plasma by radioimmunoassay (RIA) is described. The antiserum, raised against 7 alpha-methyl-19-nortestosterone-3-O-oxime-bovine serum albumin, had a low titer (final dilution = 1:4500) and low affinity (Ka = 1.17 x 10(9) l/mol) but showed little or no cross-reactivity with several of the steroids tested. The sensitivity of the RIA was 28.2 pg/ml and the mean recovery of added cold steroid was 86 to 100%. Intra- and inter-assay coefficients of variation ranged from 4.3 to 7.3% and 7.3 to 8.4%, respectively. This RIA was used to follow plasma 7MENT levels after a single i.v. injection of the steroid in rats and rabbits. The metabolic clearance rates (MCR) of 7MENT as determined from the plasma disappearance curve for rats and rabbits were 50 l/day and 336 l/day, respectively. The MCR of 7MENT in rats and rabbits lies in the same range as for testosterone. When compared to other nortestosterone derivatives such as norethisterone, 7MENT is metabolized relatively faster.

Precursors of plasma androstanediol- and androgen-glucuronides in women

Although androstanediol (AD) and androstanediolglucuronide (ADG) are generally considered to be parameters of peripheral androgen action, their plasma levels do not always vary in parallel, suggesting that they may have different precursors. Few hard data being available concerning ADG precursors in women, we studied in postmenopausal women with absent or suppressed adrenal function, the blood conversion rates of testosterone (T), dihydrotestosterone (DHT), androstenedione (A) and dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) to AD and ADG respectively, as well as the conversion of AD to ADG. Moreover conversions of these precursors to testosteroneglucuronide (TG) and dihydrotestosteroneglucuronide (DHTG), respectively, were also studied. Our data show that, whereas plasma A and DHT are the major precursors of AD, plasma DHEAS and A are the major precursors of plasma ADG, accounting for 50 and 15%, respectively, of plasma ADG, A being the major precursor of plasma TG and DHTG, respectively. When the conversion rates, obtained in this study, were applied to the plasma concentration of precursors found in normal young and postmenopausal women, respectively, the calculated concentration of product steroids accounted for almost the totality of the actual plasma levels of ADG, TG and DHTG respectively. The difference in relative importance of their precursors, explains that plasma concentrations of AD and ADG do not always vary in parallel; moreover, the importance of DHEAS as precursor of ADG explains the suppression by dexamethasone and the increase after adrenocortical stimulation of plasma ADG levels.

Time-related changes in the plasma concentrations of prolactin, gonadotropins, sex hormone-binding globulin, and certain steroid hormones in female runners after a long-distance race

Running is associated with an increase in plasma concentrations of certain anterior pituitary hormones and adrenal steroids. This study reports such increases after a marathon race. Six trained female runners, 26 to 42 years old, participated in a marathon race. Fasting (resting) blood samples were collected a few weeks before the race (baseline) and immediately (0 hour), 1 hour, and 4 hours after the run. The data were analyzed with the use of two-way analyses of variance (F-test), paired t-test, and Page's test. At 0 hour, compared with baseline, significant increases were observed in the plasma concentrations of testosterone (T), dehydroepiandrosterone sulfate (DHEA-S), cortisol (F), free T index (T/SHBG), and prolactin (PRL). At 1 hour, levels of these steroid hormones and PRL declined, some significantly. At 4 hours, levels of all hormones except DHEA-S returned to baseline. No significant changes were observed in concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and sex hormone-binding globulin (SHBG), as evaluated by F-test. Running-associated changes in plasma hormonal concentrations revert to baseline in four hours, although DHEA-S may take a little longer.

Metabolic clearance rate of plasma deoxycorticosterone sulfate in men and women

In the present investigation, we determined the metabolic clearance rate of plasma deoxycorticosterone sulfate in adult men and nonpregnant women and in one women pregnant at 42 weeks gestation with an anencephalic fetus. The values obtained varied from 618 to 10701/24 h. The metabolic clearance rate of deoxycorticosterone sulfate, expressed as a function of body surface area, was 495 +/- 31.71/24 h/m2 (mean +/- SEM) and was not significantly different among men and nonpregnant women. In a woman pregnant with an anencephalic fetus at 42 weeks gestation, the metabolic clearance rate of deoxycorticosterone sulfate was 6441/24 h/m2. We suggest that the high clearance rate of this steroid 21-sulfate, compared with those of other steroid sulfates, is due to rapid excretion of deoxycorticosterone sulfate into bile and irreversible metabolism in intestine by bacterial enzymes.

The dehydroepiandrosterone loading test. IV. Evaluation of clinical utility

This report complements the previously described preliminary clinical evaluation of the dehydroepiandrosterone (DHEA) loading test (DLT) by presenting the results of 65 DLTs in 59 patients. In patients whose fetuses were suspected of being intrauterine growth retarded, a DHEA to estrogen conversion rate constant less than or equal to 3.0 x 10(-3) min(-1) was associated with a birth weight below the tenth percentile in 60% of the pregnancies, whereas a conversion rate constant above this threshold was not associated with the same degree of growth retardation. The DLT continues to qualify as an accurate predictor of pregnancy outcome as judged by birth weight. Although it seems to be too cumbersome to serve as a screening technique, the DLT will permit evaluation of the efficacy of various pregnancy interventions directed toward improvement of the intrauterine environment, such as bed rest, tocolysis, or antihypertensive medication.

Prolactin modulation of dehydroepiandrosterone sulfate secretion

To clarify the controversy about the effect of prolactin (PRL) on dehydroepiandrosterone sulfate (DHEA-S), this study was undertaken to investigate the effects of alterations in plasma PRL on plasma DHEA-S concentrations in hyperprolactinemic women, as well as in normal male subjects. DHEA-S was measured in a group of 21 women with hyperprolactinemia, galactorrhea, and amenorrhea (PRL:257 +/- 89 ng/ml; mean +/- SEM). In these women, mean plasma concentrations of DHEA-S (2.54 +/- 0.2 microgram/ml) were significantly higher (p < 0.005) than those in 41 normal control women (1.78 z microgram/ml) and those in a group of 11 amenorrheic patients (1.77 +/- 0.2 microgram/ml). Eight women with hyperprolactinemia were given 5 mg of bromocriptine each day for 4 consecutive weeks. Within 1 week of medication, PRL levels fell by 60% (p < 0.05). To test whether lowering normal plasma levels of PRL would affect plasma concentrations of DHEA-S, five normal male subjects received a 48-hour infusion of dopamine at an average rate of 6 microgram/kg/min. Plasma levels of PRL fell by 60% (p < 0.01) after 8 hours of infusion, and DHEA-S decreased by 27% by 16 hours (p < 0.05). These data suggest that PRL modulates the secretion of DHEA-S: an increase in plasma levels of PRL is correlated with elevated concentrations of DHEA-S, whereas a decrease in PRL is followed by a fall in DHEA-S.

Breech delivery: evaluation of the method of delivery on perinatal results and maternal morbidity

A retrospective study of 460 single-gestation infants in breech position was conducted at the University of Colorado Medical Center to assess the impact of a policy for the selection of cases for vaginal delivery. Among infants weighing more than 2,500 grams, there was an increase in the cesarean section rate from 13% to 54%, with an associated increase in maternal morbidity from 7% to 15%. This occurred with no significant reduction in adverse perinatal outcome. However, a case-by-case review suggests that more frequent and timely cesarean sections would have further reduced perinatal morbidity and deaths among term infants. Among the infants weighing 2,500 grams or less there was an increase in cesarean births from 5% to 55% following the introduction of the strict criteria for vaginal delivery. Among the infants weighing 1,501 to 2,500 grams there was no significant difference in survival between the cesarean and vaginally delivered patients. Although infants weighing 501 to 1,500 grams delivered by cesarean section survived more frequently than did those delivered vaginally, the differences in perinatal deaths may have been due to a higher birth weight in the cesarean-delivered infants or an over-all improvement in neonatal intensive care for infants of very low birth weight.

Kinetics of testosterone metabolism in normal postmenopausal women and women with breast cancer

The constant infusion and single injection techniques were utilized to study the kinetics of 3H-testosterone (T) metabolism in posmenopausal women with and without breast cancer. The metabolic clearance rates (mean +/- SEM) for normal postmenopausal women were 578 +/- 82 and 644 +/- 128 1/24 has obtained by the constant infusion and single injection techniques, respectively. The corresponding results for the women with breast cancer (patients) are 644 +/- 25 and 617 +/- 106 1/24 h. The single injection technique yielded values for rate constants (units) and volumes of distribution (1); K1 = 37.5 +/- 1.6 for the normals and 34.5 +/- 1.9 for the patients, K = 76.6 +/- 5.1 for the normals and 71.1 +/- 1.6 for the patients, V1 = 7.9 +/- 2.2 for the normals and 8.7 +/- 1.4 for the patients and V2 = 7.0 +/- 1.5 for the normals and 6.4 +/- 1.2 for the patients. The constant infusion technique yielded values for the conversion ratios for the transformation of T to several products; 4-androstene-3,17-dione/T of 0.02 +/- 0.003 for normals and 0.03 +/- 0.002 for patients, 5alpha-dihydrotestosterone/T of 0.02 +/- 0.002 for normals and 0.03 +/- 0.002 for patients, estrone/T of 0.04 +/- 0.01 for normals and 0.04 +/- 0.01 for patients, estradiol-17beta/T of 0.02 +/- 0.005 for normals and 0.03 +/- 0.005 for patients and estrone sulfate/T of 0.16 +/- 0.02 for normals and 0.24 +/- 0.06 for patients. The T plasma concentrations and production rates were similar for the two groups of subjects. Hence there were no significant differences between the normals and the patients for all the kinetic parameters. It was determined that all the estradiol being produced in postmenopausal women could be coming from circulating T.

Clearance and production of dehydroepiandrosterone and its sulfate in female baboons

Serum concentrations of dehydroepiandrosterone (D) are greater and those of D sulfate (DS) are lower in female baboons than in women, suggesting interspecies differences in relative production and catabolism of these steroids. To examine this possibility, the metabolic clearance rate (MCR), interconversion (rho), and production of D and DS were determined in five adult female baboons by constant intravenous infusion of [3H]DS and [14C]D. MCR-D (mean +/- SE) was greater (407 +/- 72.8 1/day; 23.1 +/- 3.4 1/day.kg, P less than 0.01) than MCR-DS (44 +/- 5.7 1/day; 2.5 +/- 0.3 1/day.kg). rho-D leads to DS (mean % +/- SE) was greater (45.4 +/- 3.0, P less than 0.001) than rhoDS leads to D (3.8 +/- 0.6), indicating that the equilibrium favors DS formation. Calculated D production and secretion rates were similar (4.5 and 4.4 microgram/min, respectively), whereas DS production (4.1 microgram/min) was twice its secretion rate (2.1 microgram/min). The large difference between MCR-D and MCR-DS resembles that in human beings. However, when clearance is expressed per kilogram body weight, MCR-D is similar to that in man, but MCR-DS is approximately 15-fold greater in the baboon. It is concluded that compared to values in human beings, the greater MCR-DS in baboons maintains the lower serum DS concentration, whereas the higher serum D levels probably result from the relatively greater secretion rate of D baboons.

Collagenolytic activity and steroid levels after administration of dehydroepiandrosterone sulfate

Seventy-five pregnant women in the 38th to 41st weeks of gestation were given a single intravenous injection of 200 mg of dehydroepiandrosterone sulfate (DHAS). The changes in estriol, 17beta-estradiol and progesterone levels in the serum, the uterine cervix and the myometrium of the placenta-implanting site were then determined. Estriol levels remained unchanged both in serum and tissue, but the level of 17beta-estradiol increased sharply both in serum and tissue after four hours. The increases of 17beta-estradiol in the serum and the portio vaginalis of the same patient were well correlated (r = 0.79898), but the percentage of increase was much higher in the portio vaginalis than in the serum (p less than 0.001). Serum progesterone levels did not change initially, but always decreased within four or eight hours in cases in which labor had started or delivery was accomplished within 24 hours (p less than 0.01 at four hours). The total amount of collagenase was determined in ten subjects before and after the administration of DHAS. The total collagenase activity was elevated by an average of 152.3%. The peak of activity was accelerated from the fourth to the second day (p less than 0.001) of the culture. A probable mechanism of DHAS action in accelerating cervical ripening is presented.

HCG-dependent regulation of gonadotropin receptor sites: negative control in testicular Leydig cells

A single injection of human chorionic gonadotropin (hCG 500 IU) to prepubertal male rats increases plasma testosterone level and decreases hCG receptors in the testicular Leydig cells for more than 120 h. Injected hCG, measured in plasma using a specific radioreceptor assay for gonadotropins, is maximal at 2 h and decreases thereafter with an apparent half-life of 16 h. Plasma testosterone exhibits a rapid increase (30-40 ng/ml) within 1h after hCG injection. A delayed paradoxical increase (20-30 ng/ml) is observed between 48 and 120 h after the injection. The number of hCG binding sites in the isolated Leydig cells membranes decreases to less than 10% of the control value within 10 h and remains almost undetectable until 96 h after hCG injection. Reappearance of the binding sites is observed around 120 h. Similar, but less pronounced effects are found after the injection of 10 IU hCG. Since receptor occupancy cannot explain such a phenomenon, it is concluded that hCG is exerting a negative control on its own receptors in the Leydig cells.

A physiologic model of the dehydroepiandrosterone to estrogen conversion system in the fetoplacental unit. I. Development

A physiologic model of the dynamics of fetoplacental unit dehydroepiandrosterone (HDEA) to estrogen conversion is presented. A mathematical representation of this model is included. The model is used in Part II to determine the rate constant of DHEA to estrogen conversion and to successfully identify those fetuses in jeopardy from placental insufficiency within the population studied. This presentation permits critical comprehension of the model without extensive mathematical background.

Plasma dehydroepiandrosterone in pregnant and nonpregnant women

From 157 plasma samples taken randomly throughout normal pregnancy and from 42 plasma samples of nonpregnant women, total plasma dehydroepiandrosterone was measured by a method using Amberlite XAD-2 column chromatography at 45degreesC, enzyme hydrolysis, radioactive internal standard, thin-layer chromatography and gas-liquid chromatography after trimethylsilyl ether derivative formation. The following values for dehydroepiandrosterone were obtained: from individual, nonpregnant samples, (n = 25) 69.6 +/- 10.6 mug/100 ml (S.E.M.); from the pool of nonpregnant samples (n = 17) 67.7 mug/100 ml; from individual samples, 6-12 weeks of gestation (n = 32) 48.5 +/- 5.7 mug/100 ml (S.E.M.); from individual samples, 13-18 weeks of gestation (n = 13) 45.9 +/- 7.7 mug/100 ml (S.E.M.); from individual samples, 19-24 weeks of gestation (n = 20) 42.9 +/- 6.9 mug/100 ml (S.E.M.); from individual samples, 25-30 weeks of gestation (n = 22) 41.7 +/- 6.8 mug/100 ml (S.E.M.); from individual samples, 31-36 weeks of gestation (n = 31) 39.5 +/- 6.1 mug/100 ml (S.E.M.); from individual samples, 37-43 weeks of gestation (n = 29) 37.6 +/- 3.6 mug/100 ml (S.E.M.); and from the pool sample, 37-43 weeks of gestation (n = 10) 25.4 mug/100 ml. This study demonstrates a significant decrease of total plasma dehydroepiandrosterone throughout the course of normal pregnancy in individual and pooled plasma samples, thus confirming previous reports. These plasma hormone changes are discussed in relation to production and utilization of this steroid in pregnancy.

Studies on the metabolism of 5alpha-androst-16-en-3-one in boar tests in vivo

1. [5alpha-(3)H]5alpha-Androst-16-en-3-one (5alpha-androstenone) was infused at a constant rate for 180min into the spermatic artery of a sexually mature boar. Samples of spermatic-venous blood were collected at 1min intervals for the first 10min of the infusion and thereafter at 15min intervals for the first hour, then at 64, 125, 155 and 172min. After infusion, the testis was removed and immediately cooled to -196 degrees C. 2. From both the testicular tissue and the spermatic-venous plasma, endogenous and (3)H-labelled androst-16-enes were isolated, characterized and quantitatively determined and their specific radioactivity was calculated. 3. The specific radioactivities of 5alpha-androstenore, 5alpha-androst-16-en-3alpha-ol and 5alpha-androst-16-en-3beta-ol (an-alpha and an-beta) in testicular tissue were different from those in the spermatic-venous plasma, suggesting that these compounds may be present in more than one compartment of the testis and differentially secreted into the spermatic-venous blood. 4. The ratios of the specific radioactivities of an-alpha and an-beta to their respective sulphate conjugates in the testicular tissue were less than the ratios of the same compounds in the spermatic-venous plasma. 5. The patterns of secretion of these labelled compounds in the spermatic-venous blood during the period of infusion were demonstrated. 6. The urine that accumulated during the infusion was analysed and found to contain (3)H-labelled an-beta, conjugated as both glucuronide and sulphate, the specific radioactivities of which were determined. Little or no androst-16-enes occurred as free steroids. 7. The presence of an-beta glucuronide in the urine is discussed.

Estrone sulfate: production rate and metabolism in man

Since estrone sulfate (E(1)S) is present at high concentration in plasma, we have examined the parameters of the plasma estrone, estradiol, E(1)S system. The metabolic clearance rate of E(1)S was 157 liter/day (range 70-292) in men and women. Estimated plasma production rates of E(1)S were (mugrams per day): men, 77; women, early follicular phase, 95; women, early luteal phase, 182. The conversion of plasma estrone and estradiol to E(1)S was measured and from these data and the metabolic clearance rates of the estrogens, the transfer factors were rho(E) (1) (E) (1) (S) = 0.54 and rho(E) (2) (E) (1) (S) = 0.65. Using average production rates, all plasma E(1)S could be shown to be derived from plasma estrone and estradiol. The conversion of plasma E(1)S to plasma estrone and estradiol was studied. The calculated transfer factors were: rho(E) (1) (SE) (1) = 0.21, rho(E) (1) (SE) (2) = 0.014. Essentially, similar data were obtained when E(1)S was given by mouth to two subjects. WE CONCLUDE: (a) E(1)S is a major circulating plasma estrogen and has a long plasma half-life; (b) the large contributions of estrone and estradiol to plasma E(1)S are more than sufficient to account for all the circulating plasma E(1)S.