Metformin directly inhibits androgen production in human thecal cells

OBJECTIVE

To examine the direct effect of metformin on thecal cell androgen production.

SETTING

Basic science research laboratory, University of Texas Southwestern, Dallas, Texas.

INTERVENTION(S)

Human ovarian theca-like tumor cells were treated with various concentrations of metformin in the presence and absence of forskolin for 48 hours.

MAIN OUTCOME MEASURE(S)

Media were collected, and radioimmunoassay (RIA) for progesterone, 17 alpha-hydroxyprogesterone (17OHP), androstenedione, and testosterone was performed. The effect of metformin on the expression of various enzymes involved in theca cell steroidogenesis was examined.

RESULT(S)

Metformin (50 microM and 200 microM) significantly inhibited androstenedione production from both forskolin-stimulated and unstimulated theca cells. Testosterone production was also significantly inhibited in forskolin-treated cells in the presence of 200 microM of metformin-treated compared with forskolin-only-treated cells. Western blot analysis revealed that metformin significantly inhibited the expression of steroidogenic acute regulatory (StAR) protein and 17 alpha-hydroxylase (CYP17) expression in cells stimulated with forskolin compared with forskolin treatment alone. There was no significant change in either 3beta-hydroxysteroid dehydrogenase (3 beta HSD) or cholesterol side-chain cleavage (CYP11A1) protein expression. Northern analysis revealed a significant decrease in the expression of CYP17 mRNA in forskolin-stimulated cells treated with metformin (200 microM) compared with forskolin-only-treated cells, however, there was no significant change in steroidogenic acute regulatory protein mRNA expression.

CONCLUSION(S)

Our results suggest that metformin may have a direct effect on thecal cells' androgen production.

Effects of lower doses of conjugated equine estrogens and medroxyprogesterone acetate on plasma lipids and lipoproteins, coagulation factors, and carbohydrate metabolism

OBJECTIVE

To determine the effects of lower doses of conjugated equine estrogens (CEE) alone or CEE and medroxyprogesterone acetate (MPA) on lipoproteins, carbohydrate metabolism, and coagulation/fibrinolytic factors.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

Multicenter substudy of the Women's HOPE trial.

PATIENT(S)

Seven hundred and forty-nine healthy, postmenopausal women.

INTERVENTION(S)

Women were randomized to receive the following doses in milligrams per day: 0.625 CEE; 0.625 CEE/2.5 MPA; 0.45 CEE; 0.45 CEE/2.5 MPA; 0.45 CEE/1.5 MPA; 0.3 CEE; 0.3 CEE/1.5 MPA; or placebo.

MAIN OUTCOME MEASURE(S)

Assessment of lipids, lipoproteins, glucose tolerance, and coagulation/fibrinolytic factors at baseline, cycle 6, and year 1.

RESULT(S)

One year of treatment with any of the CEE or CEE/MPA regimens studied increased high-density lipoprotein cholesterol (HDL-C); the 10% increase in HDL-C for the CEE 0.45/MPA 1.5 group was similar to the CEE 0.625/MPA 2.5 group. Low-density lipoprotein cholesterol was significantly reduced in all of the active treatment groups except the CEE 0.3/MPA 1.5 group at cycle 13. Apolipoprotein A-I and triglyceride levels increased and apolipoprotein B levels decreased in all groups. The lipoprotein (a) level was reduced in the CEE 0.45/MPA 2.5, CEE 0.45/MPA 1.5, and CEE 0.625/MPA 2.5 groups. Minimal changes were observed in carbohydrate metabolism for all groups. Fibrinogen and PAI-1 activity decreased and plasminogen activity increased in all groups. Decreases in antithrombin III and protein S activities were significant for all active treatment groups except the CEE 0.3/MPA 1.5 group.

CONCLUSION(S)

Lower doses of CEE and CEE/MPA induce favorable changes in lipids, lipoproteins, and hemostatic factors with minimal changes in carbohydrate metabolism.

A role for src tyrosine kinase in regulating adrenal aldosterone production

Adrenal aldosterone synthesis is influenced by a variety of factors. The major physiological regulators of aldosterone production are angiotensin II (Ang IotaIota) and potassium (K(+)). Ang IotaIota stimulates aldosterone production through the activation of multiple intracellular signaling pathways. It has recently been demonstrated that Ang IotaIota activates src tyrosine kinases in vascular smooth muscle cells. The src family of tyrosine kinases are widely distributed non-receptor kinases that influence several signal transduction pathways. In the present study we evaluated the effect of a selective src family inhibitor, PP2, on aldosterone production using a human adrenocortical carcinoma-derived (H295R) cell line. Treatments for 6 or 48 h with PP2 (0.3 microM-10 microM) inhibited basal, Ang IotaIota, K(+) and dibutyryladenosine cyclic monophosphate (dbcAMP) stimulation of aldosterone production in a concentration-dependent manner. PP2 did not affect cell viability at any of the concentrations tested. Moreover, time course studies using PP2 (10 microM) for 6, 12, 24, and 48 h revealed a time-dependent inhibition of aldosterone production. Inhibition by PP2 (0.3-10 microM) was also observed for the metabolism of 22R-hydroxycholesterol (22R-OHChol) to aldosterone in H295R cells. Since 22R-OHChol is a substrate for cytochrome P450 side-chain cleavage enzyme (CYP11A) that does not require steroidogenic acute regulatory (StAR) protein for transport to the inner mitochondrial membrane, these results suggest that PP2 inhibition occurred beyond the rate-limiting step in aldosterone synthesis. Genistein, a non-specific tyrosine kinase inhibitor also blocked aldosterone production, but the inhibition was the result of a non-specific effect on 3beta-hydroxysteroid dehydrogenase (3betaHSD). In contrast, PP2 did not appear to act as a direct inhibitor of 3betaHSD activity. To further investigate the site of PP2 action, we examined its effect on H295R cell metabolism of [(14)C]progesterone using thin layer chromatography. PP2 treatment for 48 h caused an increase in the conversion of progesterone to 17alpha-hydroxyprogesterone. To determine if this apparent increase in 17alpha-hydroxylase activity was due to increased transcript, we examined the effect of PP2 on CYP17 mRNA. PP2 treatment caused an increase in CYP17 mRNA without an effect on 3betaHSD mRNA levels. Inhibition of protein synthesis with cycloheximide increased basal levels of CYP17 mRNA levels and blocked the induction observed by PP2. This suggests that new protein synthesis is a necessary part of PP2 induction of CYP17. Taken together these data suggest that the src tyrosine kinase inhibitor, PP2, is a potent inhibitor of aldosterone production. One mechanism for the inhibition is through an induction of CYP17 mRNA and enzyme activity. Src tyrosine kinases, therefore, may be involved with the promotion of a glomerulosa phenotype through the inhibition of CYP17 expression.

Transforming growth factor beta inhibits steroidogenic acute regulatory (StAR) protein expression in human ovarian thecal cells

In this study, we investigated the effects of TGFbeta1 on steroidogensis and expression of the steroidogenic acute regulatory (StAR) protein which regulates an important early step in the steroidogenic pathway. We utilized a human ovarian thecal like tumor (HOTT) cell model and investigated the effects of activin-A, inhibin-A, or TGFbeta1 in the presence of forskolin and the effect of dibutyryl cyclic AMP (dbcAMP) on steroid accumulation in the culture medium. Cells were also treated with different concentration of TGFbeta1 in the presence of forskolin, combined steroid production was measured at the end of 48 h and after 3 h incubation with 22R-hydroxycholesterol. In the presence of TGFbeta1 there was a dose-dependent inhibition of androstenedione production. Inhibition in combined steroid production was apparent at the highest concentration of TGFbeta1 tested. In the presence of 22R-hydroxycholesterol, combined steroid production was significantly inhibited at lower concentrations. TGFbeta1 inhibited StAR protein expression in a concentration dependent manner. There was also a similar inhibition in StAR mRNA. These results suggest that the effect of TGFbeta1 on steroid production and possibly follicular development may be in part due to its effects on StAR expression.

Developmental changes in steroidogenic enzymes in human postnatal adrenal cortex: immunohistochemical studies

Adrenarche is considered to occur as a result of intra-adrenal changes in steroidogenic enzymes involved in C19 steroid production. The present study was conducted because developmental changes in steroidogenic enzymes have not been examined well in human postnatal adrenal. Twenty-four specimens of nonpathological human adrenals from 7 months to 62 years retrieved from autopsy files. Immunohistochemistry for P450 side-chain cleavage (P450scc), 17alpha hydroxylase (P450c17), dehydroepiandrosterone sulfotransferase (DHEA-ST), P450 oxidoreductase, cytochrome b5, and 3beta-hydroxysteroid dehydrogenase (3betaHSD) was per-formed in these specimens, and the immuno-intensity was evaluated using CAS 200 computed image analysis system. Immunoreactivity of P450scc was marked in the zona glomerulosa, fasciculata and reticularis in the adrenal glands of all the cases examined. P450c17 and DHEA-ST immunoreactivity was weak in the zona fasciculata and reticularis in the adrenals of age 7 months to 5 years, but thereafter became prominent in the zona reticularis. Immunoreactivity of P450 oxidoreductase and cytochrome b5, components of the electron transfer system hypothesized to regulate the 17-20 lyase activity of P450c17, was weak in all three zones of adrenal cortex from 7 months to 5 years, and became more marked in the zona reticularis after age 5 years. 3betaHSD immunoreactivity was marked in all three zones of the adrenal cortex from 7 months to 8 years but thereafter decreased in the zona reticularis. These data suggest that the human adrenal zona reticularis markedly begins to develop morphologically and functionally at around 5 years of age. The increased level of P450c17, DHEA-ST, P450 oxidoreductase, and cytochrome b5, and the decreased level of 3betaHSD in the reticularis is likely to contribute to increased C19 steroid production during adrenarche.

Bone morphogenetic protein inhibits ovarian androgen production

Bone morphogenetic proteins (BMPs), members of the transforming growth factor beta superfamily, were recently shown to be expressed and to regulate steroidogenesis in rat ovarian tissue. The purpose of this study was to investigate the effect of BMP-4 on androgen production in a human ovarian theca-like tumor (HOTT) cell culture model. We have previously demonstrated the usefulness of these cells as a model for human thecal cells. HOTT cells respond to protein kinase A agonists by increased production of androstenedione and with an induction of steroid-metabolizing enzymes. In this investigation, HOTT cells were treated with forskolin or dibutyryl cyclic AMP (dbcAMP) in the presence or absence of various concentrations of BMP-4. The accumulation of androstenedione, progesterone, and 17alpha-hydroxyprogesterone (17OHP) in the incubation medium was measured by RIA. The expression of 17alpha-hydroxylase (CYP17), 3beta-hydroxysteroid dehydrogenase (3betaHSD), cholesterol side-chain cleavage (CYP11A1), and steroidogenic acute regulatory (StAR) protein was determined by protein immunoblotting analysis using specific rabbit polyclonal antibodies. We also examined the expression of BMP receptor subtypes in our HOTT cells using RT-PCR. In cells treated with medium alone, steroid accumulation and steroid enzyme expression was unchanged. In cells treated with BMP alone there was a modest decrease in androstenedione secretion. In the presence of forskolin, HOTT cell production of androstenedione, 17OHP, and progesterone increased by approximately 4.5-, 35-, and 3-fold, respectively. In contrast, BMP-4 decreased forskolin-stimulated HOTT cell secretion of androstenedione and 17OHP by 50% but increased progesterone production 3-fold above forskolin treatment alone. Forskolin treatment led to an increase in CYP17, CYP11A1, 3betaHSD, and StAR protein expression. BMP-4 markedly inhibited forskolin stimulation of CYP17 expression but had little effect on 3betaHSD, CYP11A1, or StAR protein levels. Similar results were observed with the cAMP analog dbcAMP. In addition, BMP-4 inhibited basal and forskolin stimulation of CYP17 messenger RNA expression as determined by RNase protection assay. Other members of the transforming growth factor beta superfamily, including activin and inhibin, had minimal effect on androstenedione production in the absence of forskolin. In the presence of forskolin, activin inhibited androstenedione production by 80%. Activin also inhibited forskolin induction of CYP17 protein expression as determined by Western analysis. We identified the presence of messenger RNA for three BMP receptors (BMP-IA, BMP-IB, and BMP-II) in the HOTT cells model. In conclusion, BMP-4 inhibits HOTT cell expression of CYP17, leading to an alteration of steroidogenic pathway resulting in reduced androstenedione accumulation and increased progesterone production. These effects of BMP-4 seem similar to those caused by activin, another member of the transforming growth factor-beta superfamily of proteins.

Progesterone receptor isoform A but not B is expressed in endometriosis

We previously demonstrated that 17beta hydroxysteroid dehydrogenase type 2, the enzyme that inactivates estradiol to estrone, is expressed in luteal eutopic endometrium in response to progesterone but not in simultaneously biopsied peritoneal endometriotic tissue. This molecular evidence of progesterone resistance, together with the clinical observation of resistance of endometriosis to treatment with progestins, led us to determine the levels of progesterone receptor (PR) isoforms PR-A and PR-B in eutopic endometrial and extra-ovarian endometriotic tissues. It was proposed that progesterone action on target genes is mediated primarily by homodimers of PR-B, whereas the truncated variant PR-A acts as a repressor of PR-B function. Immunoprecipitation, followed by Western blot analysis, was performed to detect bands specific for PR-A and PR-B in paired samples of endometriotic and eutopic endometrial tissues simultaneously biopsed from 18 women undergoing laparoscopy during various phases of the menstrual cycle. PR-B was present in 17 of 18 eutopic endometrial samples, and its level increased in the preovulatory phase, as expected, whereas PR-A was detected in all samples (n = 18) with a similar, but less prominent, cyclic variation in its levels. In endometriotic samples, however, no detectable PR-B could be demonstrated, whereas PR-A was detected in all samples (n = 18), albeit in much lower levels and without any cyclic variation in contrast with the eutopic endometrium. Levels of PR-A and PR-B in endometriotic and eutopic endometrial tissues were determined and compared after normalization to total protein and estrogen receptor-alpha levels. Using RNase protection assay, we also demonstrated indirectly that only PR-A transcripts were present in endometriotic tissue samples (n = 8), whereas both PR-A and PR-B transcripts were readily detectable in all eutopic endometrial samples (n = 8). This was indicative that failure to detect PR-B protein in endometriotic tissues is due to the absence of PR-B transcripts. We conclude that progesterone resistance in endometriotic tissue from laboratory and clinical observations may be accounted for by the presence of the inhibitory PR isoform PR-A and the absence of the stimulatory isoform PR-B.

Is there an increased risk of stroke associated with oral contraceptives?

In the last few years several studies were published about the relationship between oral contraceptive use, estrogen dose, different types of progestogens, cigarette smoking and the risk of stroke. There is a persistent association between the use of oral contraceptives containing more than 50microg of ethinylestradiol and the risk of stroke. Also, cigarette smoking seems to be a strong additive risk factor, especially in women >35 years old even with lower doses (< or =30microg) of estrogen. Unlike oral contraceptives containing >50microg of estrogen, currently there is no convincing evidence that the use of oral contraceptives containing <50microg in the absence of smoking is associated with any meaningful increase in the risk of ischaemic or haemorrhagic stroke. Progestogen-only pills are not associated with an increased risk of stroke. A specific type of progestogen in combined pills was associated with an increased risk of stroke in a few studies. Data regarding this issue is, however, inconsistent and controversial and needs further investigation. There were few if any studies that have addressed the effects of new types of progestogens (i.e. norgestimate, norgestrel or gestodene) and formulations containing 20microg of ethinylestradiol. At the present time we find no reason to alter the current practice in prescribing oral contraceptives. We do concede, however, that there might be a slight causal relationship between use of oral contraceptives containing <50microg of ethinylestradiol and stroke that did not reach statistical significance. This relationship is rare and should be viewed in context with the many benefits of oral contraceptives. Underlying risk factors for stroke such as factor V Leiden mutation and other thrombophilias might explain the role of oral contraceptive-induced stroke.

Adrenarche results from development of a 3beta-hydroxysteroid dehydrogenase-deficient adrenal reticularis

Adrenarche is the increased adrenal production of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) that occurs during the prepubertal period. To date, the exact mechanism initiating adrenarche is unknown, although many factors have been postulated. In the present study, we examined the hypothesis that alterations in intra-adrenal expression of 3beta-hydroxysteroid dehydrogenase (3betaHSD) or 21-hydroxylase (CYP21) within the inner reticularis zone leads to the increased production of 19-carbon (C19) steroids. After conversion of cholesterol to pregnenolone, 17alpha-hydroxylase/17,20-lyase (CYP17) can metabolize pregnenolone through to DHEA. The enzyme 3betaHSD competes for substrate with CYP17 and effectively removes steroid precursor from the pathway leading to DHEA. On the other hand, deficiency in CYP21 expression is known to cause excessive production of adrenal C19 steroids, suggesting that CYP21 could play a role in adrenarche. Thus, a decrease in 3betaHSD or CYP21 expression would allow substrate to flow toward the synthesis of DHEA. To determine whether adrenarche results from a decreased expression of 3betaHSD or CYP21 in the reticularis, immunohistochemical localization of 3betaHSD and CYP21 was performed, and staining intensities compared using adrenal glands from children ages 4 months to 4 yr (n = 12), ages 5-7 yr (n = 9), ages 8-13 yr (n = 9), and adults ages 25-56 yr (n = 8). There were no differences in the zonal expression of CYP21. No difference in 3betaHSD staining was observed between the glomerulosa and fasciculata from any age group. However, children age 8 yr and older show a significant decrease in 3betaHSD expression in reticularis as compared with the fasciculata. No significant difference was noted for 3betaHSD levels between the fasciculata and reticularis for children age 7 yr or younger. The level of 3betaHSD expression in the reticularis continued to decrease in the adult adrenals examined. These findings suggest that as children mature there is a decreased level of 3betaHSD in the adrenal reticularis that may contribute to the increased production of DHEA and DHEAS seen during adrenarche.

Regulation of biologically active dimeric inhibin A and B from infancy to adulthood in the male

Inhibins are glycoprotein members of the transforming growth factor-beta family that have been implicated in the control of spermatogenesis by exerting a negative feedback on FSH secretion. In addition, locally produced inhibins may play a role in paracrine regulation of testicular function. Immunoassays were used to measure the two biologically active dimeric forms of inhibin (inhibin A and B) in serum, seminal plasma, and urine. To better define their actions, inhibins were measured in the male during infancy, sexual maturation, and senescence. Inhibin B but not A was measurable in the serum of male newborns, infants, children, and adults. In adult males, measurable levels of inhibin B were detected in the seminal plasma but not the urine. The circulating levels of inhibin B increased shortly after birth and peaked at 4-12 months of age (210 +/- 31 pg/mL). The concentration measured in the serum then decreased to a low of 81 +/- 12 pg/mL of inhibin B from 3-9 yr of age followed by a gradual increase beginning with the onset of puberty and reaching another peak of 167 +/- 20 pg/mL in males who were 20-30 yr of age. Inhibin B levels then gradually declined with increasing age up through 90 yr of age. Serum levels of gonadotropins and total testosterone production were also measured in these same males. There was a brief increase in the gonadotropins (FSH and LH) during the few months of postnatal development, followed by a decrease to basal levels until the onset of puberty at 10-14 yr of age. Testosterone was also increased in the serum of infants from day 1 through 12 months of age, which decreased in young children but increased again following the elevation of gonadotropins during puberty. In adults aged 20-90 yr, serum levels of inhibin B were inversely proportional to levels of FSH but not LH or testosterone. In males in which a semen analysis was performed, those males with normal semen analysis had a significantly higher inhibin B levels, sperm production, and lower FSH levels than males with either oligospermia or nonobstructive azoospermia. The levels of Inhibin B found in circulation were a good marker for testicular function and could be useful in the diagnosis of patients with semen abnormalities or a complete absence of spermatogenesis. Because this glycoprotein is secreted in high amounts in the prepubertal testis up to 3 yr of age, inhibin B could potentially be used as a marker in the diagnosis of cryptorchidism and precocious puberty.

Effect of estradiol on DHEAS production in the human adrenocortical cell line, H295R

OBJECTIVE

To determine if estradiol regulates DHEA and DHEAS production in a human adrenocortical (H295R) cell line and to determine if this effect is receptor mediated.

METHODS

NCI-H295 (H295R) cells were rinsed and placed in phenol red free Dulbecco's Modified Eagle's-F12 medium supplemented with 0.1% charcoal-stripped serum. After 24 hours, cells were rinsed and treated based on experimental design. The effects of estradiol were investigated by: 1) treatment of cells with increasing concentrations of estradiol (300-3000 nmol/L) with or without forskolin (10 mumol/L), 2) treatment of cells with the nonsteroidal synthetic estrogen diethylstilbestrol (DES) (300-3000 nmol/L) with or without forskolin (10 mumol/L), and 3) treatment of cells with an estradiol antagonist (ICI 182, 780) in the presence of estradiol.

RESULTS

Estradiol alone increased the basal production of DHEAS in H295R cells in a concentration-dependent manner with a maximal effect at 1000 nmol/L. Forskolin treatment increased the basal production of DHEAS ten-fold. Estradiol also increased the forskolin stimulation of DHEAS production two-fold. In contrast, DES alone or DES in addition to forskolin did not stimulate DHEAS production. Estradiol, in contrast, inhibited H295R adrenal cell production of cortisol whereas DES exhibited a similar inhibition. The estrogen receptor antagonist ICI 182,780 was unable to inhibit the stimulatory effect of estradiol. Finally, estradiol in a concentration-dependent manner suppressed 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) activity in H295R adrenal cells.

CONCLUSION

These experiments support the role of estradiol in regulation DHEAS production by inhibiting 3 beta HSD activity; however, the mechanism appears to require high concentrations of estradiol and appears to be independent of the estrogen receptor.

Treatment of severe postmenopausal endometriosis with an aromatase inhibitor

OBJECTIVE

To treat an unusually aggressive case of recurrent postmenopausal endometriosis.

DESIGN

Case report.

SETTING

University of Texas Southwestern Medical Center (Dallas, Texas).

PATIENT(S)

A 57-year-old woman who presented with recurrent severe endometriosis after hysterectomy and bilateral salpingo-oophorectomy.

INTERVENTION(S)

Oral administration of anastrozole (an aromatase inhibitor) (1 mg/d) and elemental calcium (1.5 g/d) for 9 months. Alendronate (a nonestrogenic inhibitor of bone resorption), 10 mg/d, was added to this regimen.

MAIN OUTCOME MEASURE(S)

Reduction in size of endometriotic lesion, pain relief, tissue levels of aromatase P450 messenger RNA, bone density.

RESULT(S)

Circulating levels of estradiol-17beta were reduced to approximately 50% of the baseline value after the onset of treatment with anastrozole. Pain rapidly decreased and completely disappeared after the 2nd month of treatment. The 30 x 30 x 20-mm bright red polypoid vaginal lesion was reduced to a 3-mm gray tissue by the end of 9 months of treatment. Markedly high pretreatment levels of aromatase P450 messenger RNA in the endometriotic tissue became undetectable in a specimen obtained from a repeated biopsy after 6 months of treatment. Bone density of lumbar spine decreased by 6.2% after 9 months of treatment.

CONCLUSION(S)

This is the first description of the use of an aromatase inhibitor in the treatment of endometriosis. The short-term results were extraordinarily successful in elimination of pain and near-complete eradication of implants associated with severe endometriosis not responsive to other therapy. We conclude that the recently developed potent aromatase inhibitors are candidate drugs in the treatment of endometriosis that is resistant to standard regimens.

Expression of 11 beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) in the human fetal adrenal

OBJECTIVE

To understand better the steroidogenic capacity of the human fetal adrenal (HFA), we evaluated the expression of 11 beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) in the fetal zone and neocortex of the HFA using a specific RNase protection assay.

METHODS

Adrenal glands were obtained at the time of elective termination of pregnancy. Whole adrenals (n = 7) were frozen in liquid nitrogen, and subsequently total RNA extraction was performed by tissue homogenization followed by guanidinium/chloroform purification. In addition, RNA was obtained from separated fetal zone (n = 4) and neocortex (n = 4) tissues obtained by dissection. RNase protection assays were then performed using radiolabeled complementary RNA probes generated by T7 RNA polymerase directed against transcripts for CYP11B1, CYP11B2, and actin, the latter of which was used as a control for RNA integrity. Transcripts also were examined using a reverse transcription polymerase chain reaction (RT-PCR) protocol specific for CYP11B1 or CYP11B2.

RESULTS

The RNase protection assay was designed to distinguish specific bands that corresponded to CYP11B1 (232 bp), CYP11B2 (262 bp), and actin (221 bp). RNA isolated from whole HFA was observed to have high levels of CYP11B1 transcript, whereas CYP11B2 was not detected. Dissected neocortex and fetal zones were found to contain transcript for CYP11B1 using both the RNase protection assay and RT-PCR analysis. In contrast, using the RNase protection assay, CYP11B2 mRNA was not observed in the RNA from the fetal zone, but after prolonged exposure there was a band corresponding in size to CYP11B2 observed in RNA from the neocortex. Using the more sensitive RT-PCR method, transcript for CYP11B2 was found in both neocortex and fetal zone.

CONCLUSION

The HFA expresses low levels of CYP11B2 in accordance with its low production of mineralocorticoid. The expression of CYP11B1 in the fetal zone is intriguing because this enzyme is not necessary for the production of C19 steroids. Definition of the molecular mechanisms controlling expression of the CYP11B genes will be necessary to determine why the HFA differentially expresses these isoenzymes.

Estrogen and progestin components of oral contraceptives: relationship to vascular disease

Recently, new information has been published about: a) the relationship between combination oral contraceptives (OCs), estrogen dose, cigarette smoking, and the risk of myocardial infarction (MI) and stroke; and b) the effect of different progestins on the risk of venous thromboembolism (VTE). We review the epidemiologic data. Regardless of age, in the absence of smoking, use of sub-50 micrograms OCs is not associated with any meaningful increase in risk of MI or stroke. If the small, statistically nonsignificant elevations in risk for these diseases are assumed (for the sake of argument) to be causal, then the incidence of MI and stroke associated with use of OCs containing less than 50 micrograms ethinyl estradiol (EE) would be approximately 2 per 100,000 per year. For women less than 35 years of age who do not smoke or do not have a history of hypertension, the risk would be even lower. Any woman over the age of 35 who smokes should be advised to use a non-estrogen or nonhormonal contraceptive. There are now two reports, from jick et al. and Lewis et al., that demonstrate that the relative risk of MI is certainly no greater for users of OCs containing desogestrel or gestodene than for users of OCs containing older progestins. In fact, both show reduced relative risks for the newer progestins compared to the older ones. With respect to progestins, four recent epidemiologic studies have indicated a twofold increased risk of nonfatal VTE with use of OCs containing desogestrel or gestodene compared with levonorgestrel. A fifth report, which showed an increased relative risk for norgestimate, is based on use among only 19 cases and 31 controls and is not statistically significant. As the authors themselves caution and as subsequent follow-up analyses and editorials conclude, these studies do not provide evidence for a cause-and-effect relationship between OCs containing desogestrel or gestodene, and VTE. The recommendation with respect to desogestrel- and gestodene-containing OCs is that no change in prescribing practices is warranted for either current or new-start patients. There is a growing body of evidence demonstrating that OCs containing 30 or 35 micrograms of EE have lower risks of MI, stroke, and VTE than higher dose OCs. However, there is no epidemiologic study that demonstrates a greater risk of vascular events among women using OCs containing 30 or 35 micrograms EE compared with preparations containing 20 micrograms EE. Users of sub-50 micrograms OCs of any age have no clinically meaningful increase in incidence of MI or stroke compared with non-OC users. This is also true for smokers under the age of 35 years who use OCs. However, smokers over the age of 35 years who use OCs still have an unacceptably high incidence rate of MI and stroke and should not use combination OCs. Sub-50 micrograms OCs of all types are associated with a small excess risk of VTE, about 15 per 100,000 events per year. Until there is biologic explanation of the twofold greater risk of VTE in users of OCs containing desogestrel or gestodene compared with users of those containing older progestins, this association should not be accepted as one of cause and effect.

Prostaglandin E2 stimulates aromatase expression in endometriosis-derived stromal cells

C19 steroids are converted to estrogens by aromatase P450 (P450arom). Aromatase expression in humans is regulated by use of tissue-specific promoters in the placenta (promoter I.1), adipose tissue (promoters I.4, I.3, and II), and gonads (promoter II). The use of each promoter gives rise to a population of P450arom messenger ribonucleic acid (mRNA) species with a unique untranslated 5'-terminus. Aromatase is not expressed in the endometrium of disease-free women. We demonstrated, however, the presence of P450arom mRNA in pelvic endometriotic implants and eutopic endometrial curettings of women with endometriosis. In the current report, aromatase activity and P450arom gene expression were investigated in cultured stromal cells derived from eutopic endometrium and ovarian endometriomas of women with pelvic endometriosis. We also investigated the hormonal regulation of aromatase expression and alternative promoter use in these cells. The effects of interleukin-1 beta (IL-1 beta), IL-2, IL-6, IL-11, oncostatin M, IL-15, tumor necrosis factor-alpha, PGE2, estradiol, R5020, dexamethasone, and dibutyryl cAMP (Bt2cAMP) on aromatase activity in endometriosis-derived stromal cells were assessed. We chose treatments with PGs and ILs because of the inflammatory nature of endometriosis. PGE2 stimulated aromatase activity in endometriosis-derived stromal cells by 19- to 44-fold (37-221 pmol/mg protein-4 h), whereas Bt2cAMP induction was 26- to 60-fold the baseline level. No stimulation was observed by estradiol or R5020 or by IL-1 beta, IL-2, IL-6, IL-11, IL-15, or TNF alpha in the presence or absence of glucocorticoids. A modest induction of aromatase activity (2-fold) was observed in dexamethasone- plus oncostatin M-treated cells. These changes in aromatase activity were accompanied by comparable changes in the levels of P450arom mRNA levels, determined by a quantitative reverse transcription-PCR method. Promoter-specific 5'-ends of P450arom transcripts in total RNA from endometriosis-derived stromal cells treated with PGE2 and Bt2cAMP were amplified employing a novel modified rapid amplification of cDNA5'-ends/Southern hybridization method using exon-specific oligonucleotide probes. The majority of P450arom transcripts in these cells contained the gonadal-type promoter II-specific sequences, whereas very few transcripts contained adipose-type promoter I.3- and I.4-specific sequences. PGE2 appears to be the most potent known stimulator of aromatase in endometriosis. Aromatase expression in PGE2-stimulated stromal cells of endometriosis is regulated primarily by the classically located promoter II, which, in turn, is regulated by cAMP. As PGE2 is known to increase intracellular cAMP levels, estrogen biosynthesis in endometriosis may be primarily regulated by PGE2 that is locally produced. Consequent local estrogen production may promote the growth of endometriotic implants.

Re-evaluation of oral contraceptive classifications

Classification of combination oral contraceptives (OCs) by "generation"--typically based on the time of introduction of new compounds--is problematic. The estrogen and progestin components may be present in differing doses, and their interaction may therefore vary from one formulation to another. In addition, assigning the progestin component itself to a particular generation does not account for the unique characteristics of individual progestins within that group. These issues can be clarified by understanding the evolution of combination OCs in relation to dosage changes and by differentiating the pharmacologic profiles of individual progestins, particularly norgestimate, desogestrel, and gestodene. Although all sex steroids have the same basic structure, relatively minor structural modifications can cause dramatic alterations in biochemical activity. Progestational activity is the desired pharmacologic effect of progestins used in OCs, whereas androgenic activity, which increases the potential for adverse metabolic and physical side effects, is undesired. In vitro assays of the ability of various OC progestins to bind progestin and androgen receptors suggest that the androgen/progestin (A/P) binding ratio--a measure of progestin selectivity--is more favorable for norgestimate than for levonorgestrel, gestodene, or desogestrel. In vivo measurements of interactions between various progestins and human sex hormone binding globulin (SHBG) support the concept that generational classification of OC progestins is misleading. These compounds also differ clinically, as exemplified by differential effects on lipoprotein metabolism. In summary, progestins exhibit individually unique biochemical and clinical properties.

Adrenarche is associated with decreased 3 beta-hydroxysteroid dehydrogenase expression in the adrenal reticularis

The increased production of adrenal dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEAS) which occurs during the prepubertal period is known as adrenarche. One hypothesis for adrenarche is that alterations in intra-adrenal expression of steroidogenic enzymes within the inner reticularis zone leads to the increased production of 19-carbon steroids. We tested the hypothesis that at the time of adrenarche there is decreased expression of 3 beta HSD in the reticularis. Immunohistochemical localization of 3 beta HSD was performed and staining intensities compared between adrenal glands from children ages 4 months to 7 years (N = 11) and ages 8 to 11 years (N = 6). No difference was observed between the levels of staining in the glomerulosa and fasciculata from either age group. However, the reticularis from the older children exhibited diminished 3 beta HSD immunoreactivity. These findings suggest that as children mature there is a decreased level of 3 beta HSD in the adrenal reticularis which may contribute to the increased production of DHEA and DHEAS seen during adrenarche.

Human ovarian expression of 17 beta-hydroxysteroid dehydrogenase types 1, 2, and 3

Three isozymes of 17 beta-hydroxysteroid dehydrogenase (17 beta HSD) have been cloned and characterized as distinct gene products (17 beta HSD1, 17 beta HSD2, and 17 beta HSD3). The presence and location of these isozymes in the human ovary have not been defined. In this study, we utilized Northern analysis and RT-PCR to examine transcripts for the three isozymes of 17 beta HSD. RNA was isolated from ovarian cortex, stroma (pre- and postmenopausal), hilum, follicles, and corpora lutea obtained from adult women, as well as whole fetal ovaries. By Northern analysis, high levels of 17 beta HSD1 messenger RNA were found in follicles, corpora lutea, and cortex, whereas low levels were detected in the postmenopausal stroma and in fetal ovaries by RT-PCR. 17 beta HSD1 messenger RNA was not detected in hilar tissue by either Northern analysis or RT-PCR. Utilizing RT-PCR, transcripts for 17 beta HSD2 were not detectable in cortex, stroma, (pre-or postmenopausal), hilum, or follicles, but were present in RNA derived from the corpora lutea and fetal ovary. The androgenic isozyme 17 beta HSD3 was not detectable in any of the ovarian compartments examined by either Northern analysis or RT-PCR. These data provide additional insight into the mechanism of testosterone and estradiol synthesis within the ovary. Specifically, the high level of 17 beta HSD1 is clearly localized to follicles and corpora lutea indicating involvement in the synthesis of estradiol. Secondly, androgenic 17 beta HSD3 is not expressed in the human ovary. Thus testosterone production within the human ovary, occurring under physiological conditions, arises from either the 17 beta HSD1 or an uncharacterized isozyme.

HRT management: the American experience

OBJECTIVES

To review the history, current clinical practice, choice of methods and number of prescriptions and sales of hormone replacement therapy (HRT) in the US.

METHODS

Literature review, survey data collection, sales and prescription data.

RESULTS

The number of women currently utilizing HRT is greater in women aged 40-60 (35%) but falls with advancing age greater than 65 (15%) and declines further in women greater than 80 (7%). News media and physicians represent the largest source of information used by US women for information regarding HRT. Obstetricians and gynecologists currently are the predominant physicians prescribing HRT, but in the future, family practitioners and paramedical workers will prescribe HRT. Women who spontaneously develop menopause early and younger women undergoing castration are more likely to take transdermal estrogen. However, the majority of prescriptions in the US are oral estrogens (86% of the market). The market leader of oral estrogens in the US are conjugated equine estrogens (70%). Fifty percent of prescriptions in women with a uterus consist of combined continuous estrogen and progestogen whereas as 42% consist of cyclic estrogen and progestogen.

CONCLUSIONS

It appears that although there is an increase in HRT use by postmenopausal women in the US, the actual percentage of current users remains lower than anticipated. This occurred in spite of widespread media and educational efforts of benefits of HRT. Many women still fear the risk of breast and uterine cancer as well as the side effects of estrogen (primarily bleeding) which reduces the number of women currently taking estrogen. A number of surveys suggested that most women receive their information from the media and an equal amount from their physicians. With respect to estrogen use alone the majority of prescriptions are written for women without a uterus. Transdermal estrogens are used more commonly in women in the early postmenopausal period. In women with a uterus, most US physicians prescribe a combination of estrogen plus a progestogen, but when they do they utilize oral estrogen rather than transdermal estrogen.

The effect of transforming growth factor-beta on steroidogenesis and expression of key steroidogenic enzymes with a human ovarian thecal-like tumor cell model

OBJECTIVE

Our purpose was to determine the effects of transforming growth factor-beta on steroidogenesis and regulation of steroidogenic enzyme expression by use of a human ovarian thecal-like tumor cell culture system.

STUDY DESIGN

Human ovarian thecal-like tumor cells were treated in serum-free medium in the presence or absence of forskolin and transforming growth factor-beta 1. The accumulation of progesterone and androstenedione in the culture medium was evaluated by radioimmunoassay. The effects of forskolin with or without transforming growth factor-beta 1 on the enzymatic activity of P450c17 and 3 beta HSD, the expression of immunodetectable P450c17 protein, and the expression of messenger ribonucleic acid for P450scc, P450c17, and 3 beta HSD were determined.

RESULTS

Basal steroid secretion, steroidogenic enzyme activity, enzyme protein, and messenger ribonucleic acid expression were not affected by transforming growth factor-beta 1 alone. Forskolin treatment significantly stimulated steroid production and the enzymatic activity of P450c17 and 3 beta HSD up to 10-fold above basal levels. However, transforming growth factor-beta 1 inhibited forskolin-stimulated androstenedione production to near basal levels and increased progesterone 1.4- to 2-fold while suppressing P450c17 enzyme activity to near basal levels, but it did not affect 3 beta HSD activity. Forskolin-stimulated immunodetectable P450c17 alpha protein was markedly inhibited by transforming growth factor-beta 1. In addition, transforming growth factor-beta 1 markedly inhibited the forskolin-stimulation of P450c17 messenger ribonucleic acid, while not significantly altering P450scc or 3 beta HSD messenger ribonucleic acid expression.

CONCLUSION

Forskolin stimulated human ovarian thecal-like tumor cell steroidogenesis, P450c17 and 3 beta HSD activity, immunodetectable P450c17, and messenger ribonucleic acid content for P450scc, P450c17, and 3 beta HSD. Transforming growth factor-beta 1 inhibited forskolin stimulation of androstenedione production through the inhibition of P450c17 expression.

Cervical mucus anti-sperm antibodies: treatment with intrauterine insemination

PROBLEM

To determine (1) the incidence of cervical mucus anti-sperm antibodies in infertile women, and (2) the results of treatment by intrauterine insemination.

METHOD

Cervical mucus was collected the morning after urinary LH surge occurred from 153 consecutive women being treated for unexplained infertility with intrauterine insemination. Immunobead testing for IgG, IgA, IgA1, and IgA2 was performed with only actively motile sperm being counted.

RESULTS

Overall, 23/153 (15.0%) of cervical mucus samples were positive for anti-sperm antibodies: 9/23 (39.1%) were only IgA-positive (62% IgA1-positive, 38% IgA2-positive), 11/23 (47.8%) were only IgG-positive, and 3/23 (13.0%) were positive for both IgA and IgG. Insemination resulted in a pregnancy in 6/23 (26.1%) of women with cervical mucus anti-sperm antibodies after 1-3 cycles.

CONCLUSIONS

Testing for cervical mucus anti-sperm antibodies should be performed in cases of "unexplained" infertility, and intrauterine insemination may be an effective treatment, resulting in pregnancies in over one-fourth of couples.

A role for epidermal growth factor in the morphological and functional maturation of the adrenal gland in the fetal rhesus monkey in vivo

We determined the effects of epidermal growth factor (EGF) and beta-methasone on the growth and development of the adrenal gland of the fetal rhesus monkey in vivo between 121-128 days of gestation. The adrenal to body weight ratio was significantly greater (P < 0.05) in EGF-treated fetuses (0.988 +/- 0.046 x 10(-3) g/g) and significantly reduced (P < 0.05) in beta-methasone-treated fetuses (0.401 +/- 0.056 x 10(-3) g/g) compared with that in control fetuses (0.689 +/- 0.050 x 10(-3) g/g). The increase in adrenal weight with EGF administration was due to hypertrophy of definitive zone cells of the adrenal cortex, whereas the reduction in adrenal weight after beta-methasone treatment was due to a decrease in the size of definitive and fetal zone cells of the adrenal cortex. By Western analysis, EGF treatment induced a significant (P < 0.05) 2.8-fold increase in the amount of protein for 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta HSD) in the fetal adrenal. EGF also stimulated the induction of immunocytochemical staining for 3 beta HSD in transitional zone cells of the adrenal cortex. In contrast, beta-methasone resulted in 2.6-, 4.5-, and 6.6-fold significant decreases (P < 0.05) in the amount of protein for cytochrome P450 cholesterol side-chain cleavage, cytochrome P450 17 alpha-hydroxylase/17,20-lyase, and 3 beta HSD in the fetal adrenal. After beta-methasone treatment. 3 beta HSD staining was detected in some of the definitive zone cells, with no 3 beta HSD staining in the transitional zone. In conclusion, growth and functional differentiation of fetal primate adrenal gland can be accelerated prematurely by EGF and inhibited by glucocorticoid negative feedback.