Vijaya L. Nacharaju

Identification of a Kinetically Distinct Activity of 11β-Hydroxysteroid Dehydrogenase in Rat Leydig Cells1

Leydig cells are susceptible to direct glucocorticoid-mediated inhibition of testosterone biosynthesis but can counteract the inhibition through 11β-hydroxysteroid dehydrogenase (11β-HSD), which oxidatively inactivates glucocorticoids. Of the two isoforms of 11β-HSD that have been identified, type I is an NADP(H)-dependent oxidoreductase that is relatively insensitive to inhibition by end product and carbenoxolone (CBX). The type I form has been shown to be predominantly reductive in liver parenchymal cells and other tissues. In contrast, type II, which is postulated to confer specificity in mineralocorticoid receptor (MR)-mediated responses, acts as an NAD-dependent oxidase that is potently inhibited by both end product and CBX. The identity of the 11β-HSD isoform in Leydig cells is uncertain, because the protein in this cell is recognized by an anti-type I 11β-HSD antibody, but the activity is primarily oxidative, more closely resembling type II. The goal of the present study was to determine whether th...

Placental 11β-hydroxysteroid dehydrogenase activity in normotensive and pre-eclamptic pregnancies

Apparent mineralocorticoid excess and licorice induced hypertension, both hypertensive disorders, have been attributed to a defect in the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), which interconverts cortisol to cortisone. Therefore, we undertook this study to determine the role of human placental 11 beta-HSD activity in preeclampsia, which is a hypertensive disorder in pregnancy. 11 beta-HSD activities were determined in placentas of 17 normotensive and 11 preeclamptic patients matched for gestational age at 34-42 weeks. Cortisol levels in umbilical venous and arterial sera were also determined for both groups. Statistical analysis was performed using Students t-test, significance at p < 0.05. 11 beta-dehydrogenase (oxidation activity of 11 beta-HSD) activity was significantly lower in placentas of preeclamptic compared to normotensive patients (0.19 +/- 0.09 vs. 0.26 +/- 0.08 mmoles/min/placenta, p = 0.02). Cortisol level in umbilical cord blood was significantly higher in the preeclamptic group (14.99 +/- 14.08 vs. 6.71 +/- 3.69 g/dL, p = 0.02). The decreased 11 beta-HSD activity is accompanied by an expected increase in umbilical cord blood cortisol level and decrease in fetal weight. This enzyme may play an important role in influencing fetal growth.

Serum ionized magnesium and calcium in women after menopause: inverse relation of estrogen with ionized magnesium

OBJECTIVE To study the serum concentrations of the sex steroid hormones and free divalent cations Mg2+ and Ca2+ in healthy women at or past menopause and to compare them with the serum concentrations of healthy, cycling women of child-bearing age at different stages of the menstrual cycle. DESIGN Controlled clinical study. SETTING An academic medical center. PATIENT(S) Women of varying age and duration of menopause, and healthy, cycling women. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Serum levels of the sex steroids (estrogen, progesterone, and testosterone) and of Ca2+ and Mg2+ were measured in menopausal and postmenopausal women, and in healthy, cycling women at five different stages of the menstrual cycle. RESULT(S) The Mg2+ and total Mg levels of the postmenopausal women were inversely related to the serum level of estrogen and were similar to the levels present during the early follicular phase of healthy women of child-bearing age. The Ca2+ level was unrelated to the sex steroid hormones present, but it was increased compared with that of younger women in both the follicular phase and the luteal phase. CONCLUSION(S) Serum levels of Mg2+ and total Mg were inversely correlated with the estrogen concentration in menopausal women. Serum levels of Ca2+ were significantly elevated in menopausal women compared with younger women, but the ratio of Ca2+ to Mg2+, a measure of cardiovascular problems, was not elevated in the postmenopausal women.

Reproductive BiologySex Steroid Hormones Modulate Serum Ionized Magnesium and Calcium Levels Throughout the Menstrual Cycle in Women 1

OBJECTIVE To determine the serum concentrations of the sex steroid hormones with respect to the concentrations of the biologically active fractions of magnesium and calcium during the different phases of the menstrual cycle. DESIGN Controlled clinical study. SETTING An academic research environment. PATIENT(S) Six parous and four nulliparous healthy cycling female volunteers. MAIN OUTCOME MEASURE(S) Concentrations of the sex steroid hormones estrogen, progesterone, and testosterone as well as the ionized Ca and Mg levels were measured in the serum of normal cycling women during five different stages: the menstrual, early follicular, late follicular, ovulatory (ovulatory/early luteal), and luteal phases. RESULT(S) In each woman, there was a comparatively high ionized Mg level coincident with the early follicular phase, a statistically significant decrease in ionized Mg around the time of ovulation, a significant decrease in ionized and total Mg when the serum progesterone concentration peaked, and a significant increase in the serum Ca2+/Mg2+ ratio at both the ovulatory and luteal phases. In addition, a decrease in ionized Mg was found with increased testosterone levels. CONCLUSION(S) Healthy women of reproductive age demonstrate recurring cycling of ionized Mg and cyclic alterations in the ionized Ca to Mg ratio in their serum. The changes in serum concentrations of these important physiologically active cations, in the range at which they occur, can affect such entities as the vasculature, synaptic transmission, and excitation-secretion coupling and thus can produce the well-known premenstrual syndromes during the luteal phase in women who are somewhat deficient in Mg or in those who have an unusually increased Ca2+/Mg2+ ratio.

Divalent cations in women with PCOS: implications for cardiovascular disease

Polycystic ovary syndrome (PCOS) patients are known to have a high incidence of insulin resistance and glucose intolerance and tend to be at eventual high risk of hypertension ,diabetes mellitus and cardiovascular disease. It has been repeatedly shown that a low serum ionized magnesium (Mg2+) and a high ionized calcium to magnesium (Ca2+/Mg2+) ratio is often associated with insulin resistance ,cardiovascular problems ,diabetes mellitus and hypertension. We were therefore interested in assessing the serum divalent cation profile of PCOS patients compared with that of normal women of similar age. We found significantly lower serum Mg2+ and total magnesium and a significantly higher serum Ca2+/Mg2+ ratio in the PCOS patients compared with the controls. No correlation was found ,however ,between the serum concentrations of steroid hormones (estrogen ,progesterone and testosterone) ,or any of the cations in the PCOS patients or the controls.

Sulfatase Activity in Normal and Neoplastic Endometrium

Background: Dehydroepiandrosterone sulfate (DHEAS) is metabolized to active androgens and estrogens, which may have a role in the development of endometrial cancer. Methods: We studied DHEAS conversion to dehydroepiandrosterone (DHEA) in normal and neoplastic endometrium utilizing gas chromatography-mass spectral (GC-MS) analysis. Endometrial homogenate was incubated with known amounts of DHEAS for 4 h at 37°C. Methanol extract was separated from debris by centrifugation, concentrated to 200 μl and 1 μl injected into the GC-MS instrument, equipped with a CP-Sil 8 column. DHEAS and DHEA areas were calculated by autoquantization and DHEA/DHEAS ratio was used for comparing sulfatase activity among normal endometrium (n = 6), Stage I endometrioid carcinoma (EC) (n = 15), Stage I mixed mesodermal Müllerian tumor (MMMT) (n = 6) and Stage I uterine papillary serous carcinoma (UPSC) (n = 7). Results: DHEA/DHEAS ratios in normal endometrium, EC, MMMT and UPSC were 1.45 ± 1.10, 5.63 ± 3.27, 2.88 ± 0.99, and 3.04 ± 1.76, respectively. Sulfatase activity was significantly higher in EC when compared with normal endometrium (p < 0.001), MMMT (p < 0.05), and UPSC (p < 0.05). The enzyme activity did not differ significantly between low-grade and high-grade EC tumors (5.8 ± 2.77 and 5.49 ± 3.84, respectively, p > 0.05). Conclusion: Stage I EC have higher sulfatase activity than normal endometrium, and Stage I MMMT and UPSC tumors.

Presence of 11β-hydroxysteroid dehydrogenase in human semen: Evidence of correlation with semen characteristics

11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), the enzyme that catalyzes the conversion of biologically active glucocorticoids to their inactive metabolites, was shown to be located exclusively in Leydig cells of the rat testis, and its appearance was associated with the developmental rise in testosterone. Thus, 11 beta-HSD was suggested to play an important role in maintaining steroidogenesis by inactivating excess cortisol that inhibits testosterone production. Whether equivalent protection from glucocorticoids excess is necessary for spermatogenesis is not known, and we have, accordingly, investigated the 11 beta-HSD activity in ejaculated human semen. Both 11 beta-dehydrogenase (11 beta-DH) and 11 beta-oxoreductase (11-OR) activities of 11 beta-HSD were measurable in semen, although seminal plasma was devoid of 11 beta-HSD activity. Azoospermic specimens were associated with low 11 beta-dehydrogenase activity, indicating the presence of enzyme activity in cells other than spermatozoa. Pure spermatozoa separated on percoll gradient could oxidize corticosterone in the presence of NAD or NADP. Significantly higher 11 beta-DH activity is associated with semen specimens with low sperm count (p < .05) and higher level of morphologically abnormal spermatozoa (p < .05). The presence of 11 beta-HSD in human semen and its association with sperm characteristics thus suggests functional role for glucocorticoid exclusion in the sperm maturation process.

11β‐Hydroxysteroid Dehydrogenase Inhibitor Carbenoxolone Stimulates Chorionic Gonadotropin Secretion from Human Term Cytotrophoblast Cells Differentiated In Vitro*

Problem:  To investigate the effect of altering local glucocorticoid concentration on human chorionic gonadotropin (hCG) production by cultured placental trophoblast cells.

Circulating Divalent Cations in Asymptomatic Ovarian Hyperstimulation and in vitro Fertilization Patients

It is known that ovarian hyperstimulation and in vitro fertilization are accompanied by a steady increase in circulating estrogen and progesterone far beyond what is normal for young women. We have recently demonstrated that the biologically active fractions of calcium and magnesium in blood are altered depending on when in the menstrual phase a blood sample is drawn in normal cycling women. The serum ionized Ca/Mg ratio is also altered in accordance with the menstrual cycles. This suggests that the sex steroid hormones may modulate serum levels of ionized Mg and the ionized Ca/Mg ratio. We therefore studied the relationships between sex steroid hormones and the concentrations of ionized magnesium and calcium in the blood of hyperstimulated patients. We were able to demonstrate that with each increment in estrogen, a decrease in ionized Mg occurred, and as the progesterone rose in the blood, the ionized Ca/Mg ratio increased. Our results support the idea that serum estrogen and progesterone levels in women modulate the blood levels of circulating ionized Mg and the serum ionized Ca/Mg ratio.

NAD Dependent 11β-Hydroxysteroid Dehydrogenase Activity in Human Endometrium and Endometrial Tumors

Background: The isoforms of 11β-hydroxysteroid dehydrogenase (11β-HSD) types 1 and 2, regulated by ovarian steroids, catalyze the interconversion of glucocorticoids and their 11-keto metabolites. The role of these enzymes in malignancies of human endometrium is unknown. We compare NAD dependent 11β-HSD (type 2) activity levels among normal human endometrium and endometrial carcinomas of differing grades and histologies. Methods: NAD dependent 11β-HSD activity was determined in endometrial tissue obtained from patients undergoing hysterectomy for benign or malignant disease (endometroid, serous and carcinosarcomas). Student’s t test was utilized with p < 0.05 considered significant. Data are presented as mean ± SD. Results: NAD dependent 11β-HSD activity was present in all endometrial samples. The activities were 0.61± 0.27 in normal (n = 9), 0.43 ± 0.29 in endometrioid endometrial carcinoma (n = 14), 0.50 ± 0.26 in uterine serous carcinoma (n = 6) and 0.25 ± 0.37 in carcinosarcomas (n = 9). NAD dependent 11β-HSD activity was lower in the carcinosarcoma group as compared to normal endometrial tissue (p = 0.03). Conclusions: NAD dependent type 2 11β-HSD activity was demonstrated in all normal and endometrial tumors. Enzyme activity in endometroid and uterine serious carcinoma tumors was similar to enzyme activity in normal endometrium. In contrast, carcinosarcomas show significantly lower enzyme activity compared to normal tissue.