Rajesh S. Mathur

Testosterone Increases Human Platelet Thromboxane A2 Receptor Density and Aggregation Responses

BACKGROUND The incidence of thrombotic cardiovascular disease is greater in men than in premenopausal women. Testosterone has been implicated as a significant risk factor for cardiovascular disease and for acute myocardial infarctions and strokes in young male athletes who abuse anabolic steroids. Thromboxane A2 (TXA2) is a vasoconstrictor and platelet proaggregatory agent that has been implicated in the pathogenesis of cardiovascular disease. We therefore tested the hypothesis that testosterone regulates the expression of human platelet TXA2 receptors. METHODS AND RESULTS In a double-blind, placebo-controlled, randomized, parallel-group study, we determined the effects of testosterone cypionate 200 mg IM given twice, 2 weeks apart, or saline placebo in 16 healthy men. Platelet TXA2 receptor density (Bmax) and dissociation constant (Kd) were measured by use of the TXA2 mimetic 125I-BOP. Platelet aggregation responses to I-BOP and to thrombin and plasma testosterone concentrations were measured before treatment (pretreatment phase), at 2 and 4 weeks (active phase), and again at 8 weeks (recovery phase). Treatment with testosterone was associated with an increase in the Bmax value from 0.95 +/- 0.13 to 2.10 +/- 0.4 pmol/mg protein (n = 9), with a peak effect at 4 weeks (P = .001), returning to baseline by 8 weeks. There was no significant change in Bmax values in the saline-treated group. The Kd values were unchanged. Testosterone treatment was associated with a significant increase in the maximum platelet aggregation response to I-BOP (P < .001) at 4 weeks and returned to baseline at 8 weeks. The EC50 values were not significantly changed. Platelet TXA2 receptor density was positively correlated (r = .56, P < .001, n = 32 measurements) with pretreatment (endogenous) plasma testosterone levels (range, 215 to 883 ng/dL) but not Kd. CONCLUSIONS Testosterone regulates the expression of platelet TXA2 receptors in humans. This may contribute to the thrombogenicity of androgenic steroids.

Female runners and secondary amenorrhea: correlation with age, parity, mileage, and plasma hormonal and sex-hormone-binding globulin concentrations*†

Twenty-three white women, ages 18 to 42, with normal menses prior to running were studied. Miles per week varied from 10 to 70 for a period of 1 to more than 10 years. Of these, 6 were amenorrheic (AM), 14 had regular cycles (REG), and 3 with regular cycles became amenorrheic during the course of this study. The incidence of amenorrhea was higher in those less than 30 years of age (66.6%) than in the older group (9.0%); in those who ran 40 miles/week or less (37.5%) than in those who ran more (26.6%); and in the nulliparous (46.6%) than in the parous runners (25.0%). The age of menarche was significantly higher in the AM (13.8 +/- 0.5 years) than in the REG (12.2 +/- 0.3 years). Blood samples were collected between 12 and 24 hours after the last run for hormonal and sex-hormone-binding globulin (SHBG) measurements. Plasma estradiol (E2), SHBG, and LH were significantly lower in the AM than in the REG group. Furthermore, E2, LH, and prolactin were significantly lower in the AM group than in the control group. These results suggest that the incidence of secondary amenorrhea is higher in younger, nulliparous female runners and may be related to delayed onset of menarche.

Plasma Androgens and Sex Hormone-Binding Globulin in the Evaluation of Hirsute Females *

Hirsutism is usually associated with increased testosterone (T) production and metabolic clearance rates. Considerable overlap of plasma T occurs between hirsute and normal groups. Plasma levels of sex hormone-binding globulin (SHBG) and the factor T/SHBG might separate hirsute patients from normal subjects better than plasma T. A group of 39 hirsute females and 22 normal ovulatory control subjects were studied. Plasma T, androstenedione, and dehydroepiandrosterone were measured by radioimmunoassay; apparent free T (AFT) by equilibrium dialysis; and SHGBG by a method based on saturating the binding sites by labeled dihydrotestosterone. Mean levels of androgens and SHBG of the hirsute patients were significantly different from those of the normal subjects (P less than 0.01). Positive linear correlations were observed between T and AFT, T/SHBG and AFT, and T/SHBG and T; a negative correlation was observed between T/SHBG and SHBG, but no correlation was observed between SHBG and T or AFT. Thirty (77%) of the patients had elevated T/SHBG factors and 28 (72%) had suppressed SHBG levels. Only two patients (5%) had hirsutism associated with normal levels of androgens, SHBG, and T/SHBG. We conclude that SHBG and the factor T/SHBG separate the hirsute population better than any of the androgens studied.

Cyclic variations in white cell subpopulations in the human menstrual cycle: Correlations with progesterone and estradiol

Cyclic variations in white cell subpopulations were studied in serial blood samples from 18 female volunteers (14 ovulatory and 4 nonovulatory cycles) and 2 males. Total white blood cells (WBC), lymphocytes, total and active T cells (TEt, TEa), monocytes, and granulocytes were counted, and levels of estradiol (E2), progesterone, and luteinizing hormone (LH) were measured. In the ovulatory cycles, lymphocyte counts at midcycle (Day 0) reached a minimum, coinciding with the maximum level of E2 peak (35 ng%). In daily samples, the minimum lymphocyte counts coincided with the preovulatory E2 surge (P < 0.01). Similar but less significant negative correlations (P < 0.05) were found between E2, WBC, and TEt. In contrast, TEa did not show cyclic variations. Monocyte and granulocyte counts were significantly higher in the luteal than in the follicular phase (P < 0.05); their pattern followed closely that of progesterone (P < 0.05) but not of E2. Daily evaluations of hematocrit, hemoglobin content, red blood cell count, and mean corpuscular volume failed to show cyclic variations. For the females with nonovulatory cycles and for the males studied (with sex steroid profiles corresponding to the follicular phase), no cyclic variations were found in white cell subpopulations.

Testosterone treatment enhances thromboxane A2 mimetic induced coronary artery vasoconstriction in guinea pigs

Abstract. Thromboxane A2 (TXA2) has been implicated as an important mediator of cardiovascular diseases. There have been several clinical reports of acute myocardial infarctions occurring in young male athletes abusing anabolic steroids. The effects of treatment of male Guinea pigs with testosterone on the responses to U46619, a TXA2 receptor agonist, in the isolated perfused heart were determined. The maximum pressor responses of the isolated perfused Guinea pig heart to U46619 were significantly (P < 0·05) greater in the Guinea pigs treated with testosterone compared to the controls. These results indicate that testosterone can enhance coronary artery vascular reactivity to TXA2.

The effect of estrogen treatment on plasma concentrations of steroid hormones, gonadotropins, prolactin and sex hormone-binding globulin in post-menopausal women

Twenty-one post-menopausal women on no other medication were treated with a low dose (0.625 mg/day) of conjugated equine estrogen (CEE) for a mean (+/- SEM) period of 2.6 +/- 0.2 mth (range 1.75-4.75). Blood samples were collected before and at the completion of therapy, and alterations in the levels of prolactin (PRL), follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG) and certain steroid hormones, including the free testosterone (T) index (T/SHBG) were studied. Following treatment, a significant increase in SHBG levels produced a significant decrease in the free T index (P less than 0.005). As expected, no changes were observed in the levels of PRL and steroid hormones other than estrone (E1) and estradiol-17-beta (E2). Our observations indicate that treatment of post-menopausal women with low-dose estrogen lowers the unbound T.

Plasma gonadotropins, prolactin, and steroid hormone concentrations in female runners immediately after a long-distance run

Six normally menstruating women who regularly run participated in a 10-mile race. Blood samples were collected within 20 minutes after the completion of the race (group 1). Samples were analyzed, and the results were compared with plasma hormonal concentrations in the same runners in samples collected between 12 and 24 hours after a previous practice run (group 2) and with our nonathletic female controls. Plasma concentrations of the following hormones in group 1 were significantly elevated when compared with group 2: dehydroepiandrosterone (DHA), androstenedione (delta 4A), testosterone (T), cortisol (F), luteinizing hormone (LH), and prolactin (PRL). Levels of 17 beta-estradiol (E2), 17-hydroxyprogesterone (17-OHP), dehydroepiandrosterone sulfate (DHAS), and follicle-stimulating hormone (FSH) were comparable in groups 1 and 2. However, DHAS in group 1 was elevated when compared with controls, as were HDA, delta 4A,T,F,LH, and PRL. In group 1, but not in group 2, a significant correlation (P less than 0.05) was observed between plasma LH and PRL concentrations but not between FSH an PRL. We conclude that the immediate effect of running is reflected in increased levels of the adrenal androgens, F, LH, and PRL. However, concentrations of these hormones revert back to baseline within 12 to 24 hours after the race.

Gender-related differences in androgen regulation of thromboxane A2 receptors in rat aortic smooth-muscle cells

Thromboxane A2 (TXA2) has been implicated as an important mediator of cardiovascular diseases. Aortas obtained from male rats are more sensitive to TXA2 mimetics compared with those obtained from females. A similar phenomenon has been reported in canine coronary arteries. To determine whether there is a gender-related difference in the regulation of TXA2 receptors by androgenic steroids, we determined the effect of testosterone and dihydrotestosterone (DHT) on TXA2 receptor density in cultured rat aortic smooth-muscle (RASM) cells and guinea pig coronary artery smooth-muscle (CASM) cells. TXA2 receptor density (B(max)) and dissociation constant (Kd) were determined by radioligand binding studies with (125)I-BOP, a TXA2 receptor agonist. Testosterone significantly (p < 0.05) increased TXA2 receptor density in cultured RASM cells and guinea pig CASM cells. DHT significantly (p < 0.005) increased the B(max) in male RASM cells (62 +/- 2 vs. 40 +/- 3 fmol/mg protein; n = 7; p < 0.005). DHT increased the B(max) values in both male and female RASM cells, but the increase was significantly (p < 0.05) less in female than in male RASM cells (57 +/- 10% increase for male and 31 +/- 5% for female). Androgen-receptor protein was detected in RASM cells by Western blot and was less in the female RASM cells than in the male. The results indicate that RASM cells possess an androgen receptor and that gender-related differences exist in the regulation of expression of TXA2 receptors by androgens.

Progesterone, 17-hydroxyprogesterone, estradiol, and estriol in late pregnancy and labor

Levels of progesterone, 17 alpha-hydroxyprogesterone, estradiol, and estriol were measured in serial plasma samples collected from 30 uncomplicated pregnancies during the last eight weeks of gestation. From another group of 27 uncomplicated pregnancies, blood samples were collected during the second stage of labor and the same steroids were measured. Progesterone, 17-hydroxyprogesterone, and estradiol levels were highest during the last one to three weeks prior to the onset of labor, whereas estriol concentration increased progressively. The levels of these steroids during the second stage of labor were statistically not different from those just preceding labor. It is concluded that the onset of human labor is not associated with marked changes in the maternal levels of any of these steroids.

Cervical epidermal growth factor-receptor (EGF-R) and serum insulin-like growth factor II (IGF-II) levels are potential markers for cervical cancer.

PROBLEM: To ascertain if cervical epithelial epidermal growth factor receptor (EGF‐R) and serum insulin‐like growth factor II (IGF‐II) levels are potential markers for cervical cancer.
 METHOD OF STUDY: We tested cervical biopsies obtained from 18 controls, 3 women with cervical intraepithelial neoplasia (CIN) I, 17 women with CIN II and III, and 12 women with cervical cancer for EGF‐R using a quantitative immunofluorescent antibody assay. We measured serum IGF‐II levels using an enzyme‐linked immunosorbent assay in 20 controls, 26 CIN patients, 12 with cervical cancer before therapy, 5 with cervical cancer for <1 year, and 9 others ≥1 year after therapy.
 RESULTS: The levels of cervical EGF‐R in women with CIN and cervical cancer were significantly higher (P<0.05 for CIN I; P<0.001 for patients with CIN II and III or cervical cancer) than in controls. Women with cervical cancer (P<0.001 vs. controls) or advanced CIN (P=0.03) had elevated levels of serum IGF‐II, while the women with CIN I had levels similar to controls. Women with cervical cancer in the post‐therapy period had significantly lower serum IGF‐II levels than the women with cervical cancer before therapy (P<0.001).
 CONCLUSION: Cervical epithelial EGF‐R and serum IGF‐II levels may be used for the diagnosis and prognosis of cervical cancer.