Origin Of Estrogens Research Articles

Local biosynthesis and metabolism of oestrogens in the human breast

The origin of oestrogens at the level of the breast itself is discussed. In particular in postmenopausal women an accumulation of oestradiol at the site of breast tumours has been documented by a number of independent studies. The mechanism behind the high local oestrogens concentrations is thought to be the in situ production of these steroids by local processes with androstenedione as the main precursor. The presence of all enzymes required for this production has been demonstrated in a large proportion of breast tumours, with probably aromatase, hydroxysteroid dehydrogenase type 1 and sulfatase as the most important enzymes leading to the biologically highly active oestradiol. The individual enzymes that are relevant for the biosynthesis and the metabolism of oestrogens are discussed. The conclusion is reached that a number of these local processes may be involved in the promotion of premalignant lesions and in stimulation of growth of malignant tumours in the human breast.

Interferon alfa-2c and proteinuria in a patient with focal and segmental glomerulosclerosis

Vol 349 • April 19, 1997 1147 women. JAMA 1991; 265: 1861–67. 2 MacDonald PC, Madden JD, Brenner PF, Wilson JD, Siiteri PK. Origin of estrogen in normal men and in women with testicular feminization. J Clin Endocrinol Metab 1979; 49: 905–16. 3 Bagatell CJ, Knopp RH, Rivier JE, Bremner WJ. Physiological levels of estradiol stimulate plasma high density lipoprotein2 cholesterol levels in normal men. J Clin Endocrinol Metab 1994; 78: 855–61. 4 Smith EP, Boyd J, Frank GR, et al. Estrogen resistance caused by a mutation in the estrogen-receptor gene in a man. N Engl J Med 1994; 331: 1056–61. 5 Celermajer DS, Sorensen KE, Gooch VM, et al. Non-invasive detection of endothelial dysfunction in children and adults at risk of atherosclerosis. Lancet 1992; 340: 1111–15.

The origin of estrogens, progesterone, androgens and sex hormone binding globulin in peritoneal fluid in the immediate postovulatory period in normal ovulating women

In 20 women with proven fertility, one menstrual cycle was monitored by ovarian ultrasonography, laparoscopy and estimation of 17 beta-estradiol (E2), estrone (E1), progesterone, testosterone, androstenedione (Adion), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), and sex hormone binding globulin (SHBG) in serum and peritoneal fluid. Three groups were studied, in which the peritoneal fluid was collected within 1, 3 and 5 days after ovulation. E1, E2 and progesterone levels in peritoneal fluid were highest shortly after ovulation and decreased with time. Testosterone and Adion in peritoneal fluid showed no changes, but peritoneal fluid levels were always higher than serum levels. No differences were found between the peritoneal fluid and serum levels of DHEA and DHEAS. SHBG in serum was always higher than in peritoneal fluid. The results are compared with reported steroid levels in follicular fluid from the literature and factors complicating the interpretation of steroid levels in peritoneal fluid are discussed.

Origin of estrogen in normal men and in women with testicular feminization.

The purpose of this study was to quantify the various sources of estrone (E1) and 17 beta-estradiol (E2) production in normal men and in women with testicular feminization. The mean production rate of E1 in four young adult men was 58 micrograms/24 h, while that of E2 was 44 micrograms/24 h. In these men, E1 production could be accounted for totally by extraglandular formation through 1) aromatization of plasma androstenedione, 2) conversion of E2 which was formed from the aromatization of plasma testosterone, and 3) conversion of secreted E2. In these men, only 12 micrograms or less of E2 production could not be accounted for by extraglandular formation from plasma C19 precursors, and is presumed to have arisen by testicular secretion. In six women with testicular feminization, the mean production rate of E1 was 99 micrograms/24 h, while that of E2 was 77 micrograms/24 h. THe amount of E2 production that arose by glandular secretion could be computed in four of these women and was considerably greater than that found in the young adult men. In these women with testicular feminization, an average of 44 micrograms/24 h E2 could not be accounted for by extraglandular formation and is presumed to have arisen by testicular secretion. The mean plasma production rate of testosterone in the normal men was 5.7 mg/24 h, while that in the women with testicular feminization was 8.3 mg/24 h. However, the range of plasma production rates of testosterone in the women with testicular feminization was large (1.3--17.0 mg/24 h).

Production and origin of estrogen in two true hermaphrodites

Two 46,XX true hermaphrodites with genital ambiguity since birth and gynecomastia were studied. The production rates of estradiol in these subjects, 77 and 71 μg per 24 hours, and of estrone, 82 and 136 μg per 24 hours, were approximately twice those of normal adult men. In one of these subjects the plasma production rates of androstenedione and testosterone were measured and found to be 389 and 1,271 μg per 24 hours, respectively. In this subject all estrone production, 82 μg per 24 hours, could be accounted for by extraglandular formation from plasma prehormones, whereas 71 μg of estradiol per 24 hours could not be accounted for by extraglandular formation and presumably arose from glandular secretion. The concentration of testosterone in the testicular portion of the ovotestis of this subject was 465 ng. per gram of tissue, a value comparable to that found in testicular tissue obtained from adult men. In the other subject of this study, who had a malignant gonadal tumor, the plasma concentration of human chorionic gonadotropin was 3,000 ml.U. per milliliter. From the results of this study we conclude that both ovarian and testicular components of the gonads of these two individuals were endocrinologically active, and that their gynecomastia likely developed as a consequence of gonadal estradiol secretion.

Analysis of a dexamethasone-chorionic gonadotrophin test of adreno-gonadal function in normal men as compared with dexamethasone test in normal women.

ABSTRACT 42 normal men aged 20–40 years were subjected to a functional test involving chorionic gonadotrophin (HCG) stimulation performed during dexamethasone suppression of the adrenals and with determinations of urinary androgen and oestrogen metabolites. For comparison, dexamethasone suppression was performed in 21 normal women aged 20–40 years. Steroids of adrenal origin were determined as the difference of values before and during dexamethasone suppression, and testicular reserve capacity as the difference before and after HCG. Furthermore, some ratios between steroids were calculated, and a total of 27 steroid parameters were obtained. Normal means and normal limits are given for all these parameters. All parameters were subjected to mutual correlation analyses. These showed, among several other findings, the following: Leydig cell reserve capacity for androgen falls significantly with age; adrenal and gonadal sex hormone productions are independent of each other in men but not in women; men have a significant adrenal androgen production which is not related to the adrenal production of dehydroepiandrosterone; testicular reserve capacity is not correlated with the spontaneous testicular steroid production; a high correlation exists between dehydroepiandrosterone and oestrogen excretion in men; the testicular reserve capacities for androgen and oestrogen are completely independent of each other. From these and other findings, sex hormone relationships and particularly the origin of oestrogens in men are discussed.

Studies on the Urinary Excretion, Biological Effects and Origin of Oestrogens in Post-Menopausal Women

Studies on the Urinary Excretion, Biological Effects and Origin of Oestrogens in Post-Menopausal Women

ORIGIN OF ESTROGEN IN WOMEN PREGNANT WITH AN ANENCEPHALIC FETUS.

ORIGIN OF ESTROGEN IN WOMEN PREGNANT WITH AN ANENCEPHALIC FETUS.