Sila Banerjee

Postmenopausal endogenous oestrogens and risk of endometrial cancer: results of a prospective study.

We assessed the association of postmenopausal serum levels of oestrogens and sex hormone-binding globulin (SHBG) with endometrial cancer risk in a case–control study nested within the NYU Women’s Health Study cohort. Among 7054 women postmenopausal at enrolment, 57 cases of endometrial cancer were diagnosed a median of 5.5 years after blood donation. Each case was compared to 4 controls matched on age, menopausal status at enrolment, and serum storage duration. Endometrial cancer risk increased with higher levels of oestradiol (odds ratio = 2.4 in highest vs lowest tertile, P for trend = 0.02), percent free oestradiol (OR = 3.5, P< 0.001), and oestrone (OR = 3.9, P< 0.001). Risk decreased with higher levels of percent SHBG-bound oestradiol (OR = 0.43, P = 0.03) and SHBG (OR = 0.39, P = 0.01). Trends remained in the same directions after adjusting for height and body mass index. A positive association of body mass index with risk was substantially reduced after adjusting for oestrone level. Our results indicate that risk of endometrial cancer increases with increasing postmenopausal oestrogen levels but do not provide strong support for a role of body mass index independent of its effect on oestrogen levels.

Serum estradiol-binding profiles in postmenopausal women undergoing three common estrogen replacement therapies: associations with sex hormone-binding globulin, estradiol, and estrone levels.

Objective: To compare the effects of three commonly prescribed estrogen replacement therapies—oral conjugated equine estrogens (CEE; n = 37), oral micronized estradiol (ME; n = 25), and transdermal estradiol (TE; n = 24)—on the binding characteristics of plasma estradiol as related to the concentrations of blood sex hormone‐binding globulin (SHBG), estradiol, and estrone. Design: Menopausal volunteers, opting for estrogen replacement therapy, gave blood at 0, 2, and 4 months. SHBG was assayed by automated immunoabsorbent technology. Estradiol and estrone were determined by quantitative gas chromatography/mass spectrometry. After tritiated estradiol was added to serum, the percentage of estradiol not bound to protein was determined by ultrafiltration and the percentage of estradiol bound to SHBG was measured by a method exploiting that this protein, even when bound to estradiol, binds avidly to Concanavalin A‐Agarose. Results: In each study, 2‐ and 4‐month data were similar. Increases in SHBG concentrations were 100% (p < 0.001), 45% (p < 0.001), and 12% (nonsignificant) for subjects who were receiving CEE, ME, and TE regimens, respectively. Decreases in the percentage of estradiol not bound to protein and increases in the percentage of estradiol bound to SHBG correlated with changes in the concentrations of this protein mediated by the therapies. The order for increases in estradiol was ME∽TE >> CEE, whereas for estrone, the order was ME > CEE >> TE, divergent from the SHBG responses. Conclusions: The diverse responses observed can be explained by differences in the estrogen load delivered to target tissues as controlled by the intermediary circulation and metabolism of the hormones introduced in these regimens. (Menopause 2000;7:243‐250.

An estrogen-dependent esterase activity in MCF-7 cells

The presence of steroidal esters in hormonally sensitive tissues lends importance to the esterases which convert the biologically inactive adducts to the parent potent forms. Accordingly, esterase-activities were studied in a human breast cancer model--the MCF-7 cell line. Tritiated estradiol esters- estradiol-17-acetate (EA), estradiol-17-valerate (EV) and estradiol-17-stearate (ES) were tested systematically, but 3 beta-ol esters of androgens, and phorbol diesters were also investigated. All compounds tested, except the phorbol diesters were hydrolyzed either when added to growing cultures or to the 28,000 g supernate of homogenized MCF-7 cells. Among the estrogens, the relative rates of hydrolysis were EA greater than EV greater than ES. The esterase for EA was different as it was not inhibited by saturating concentrations of EV or ES, and unlike the others its activity was stimulated by the addition of estradiol to the culture medium. The antiestrogen keoxifene,[(6-Hydroxy-2-(4-hydroxyphenyl)benzo less than b greater than thien-3-yl greater than less than 4- less than 2-(1-piperidinyl)ethoxy greater than phenyl greater than methanone], negated the stimulatory effect. Other major classes of steroids did not influence EA esterase activity. Results of inhibition experiments indicated that the esterases are of the serine active-site types. The significance of the estrogen-dependent esterase activity can be assessed when the natural substrate(s) for the enzyme is elucidated.

Correlation of concentrations of estriol-3-sulfate with those of potassium and sodium in human breast cyst fluid

Estriol-3-sulfate (E3-3S) was assayed in 92 specimens of human breast cyst fluid (BCF) obtained by needle aspiration from women with fibrocystic disease. The concentrations of K+ and Na+ were determined in the same samples. The median concentration of E3-3S in the fluids from premenopausal women under 51 years of age (69 cases) was 4.4 ng/mL. Based on the K+ levels the samples were divided into two groups, above 50 mM (Type I) and below 50 mM (Type II). Correlations were made between the concentrations of the estrogen conjugate and the univalent ions. In the premenopausal women, Type I cysts were associated with above median E3-3S and Type II cysts with below median E3-3S (P less than 0.01). A K+/Na+ ratio of more than one was also related to elevated E3-3S (P less than 0.025). The BCF obtained from postmenopausal women and women older than 50 years tended to be low in E3-3S (median 1.64 ng/mL) and high in K+ but there were too few cases to permit statistical comparisons to be made. Since fibrocystic disease constitutes a risk factor for the development of breast cancer, it will be of interest to determine retrospectively whether any of the above subsets of BCF may be useful in identifying a patient at such risk.

On the processing of saliva samples for progesterone assay

Reports from several laboratories indicate that the concentration of progesterone in the saliva provides a valid indicator of corpus luteum function. However, optimal conditions for the treatment and storage of saliva specimens prior to analysis was not addressed in these papers. We have found that 1) sonication of saliva in brief bursts produces a homogeneous sample from which progesterone is removed quantitatively by a single extraction with hexane in a vortex mixer, and 2) prompt freezing of saliva is important since storage of samples at room temperature for 48 hours results in a significant decrease in radioimmunoassayable progesterone. Four normal women provided daily saliva specimens throughout one menstrual cycle and serum samples every 3 days during the luteal phase. Excellent correlations between the progesterone profiles in the two fluids were obtained.

Peptide Mapping Studies of the Chromogranins and of Two Chromaffin Granule Proteoglycans

Abstract: The chromogranins, a family of related acidic glycoproteins, and two chondroitin sulfate/dermatan sulfate proteoglycans were isolated from the soluble contents of bovine adrenal chromaffin granules by chromatography on DEAE‐cellulose. These chromaffin granule matrix glycoconjugates were treated with trypsin, and the resulting peptides were fractionated by HPLC. The two proteoglycans, which differ in their concentration of glycosaminogly‐cans and glycoprotein oligosaccharides, yielded almost identical peptide patterns and would both appear to have the same protein moiety. The peptide profile of the proteoglycans differs, however, from that of the chromogranins, which they closely resemble in terms of amino acid composition. The various chromogranin fractions obtained by gel filtration were also found to have significant differences in the chromatographic patterns of their tryptic peptides.

A Role for Esterases in Steroid Hormone Turnover

Studies attempting to elucidate the physiological role of esterases have been complicated by their lack of specificity exhibited and the overall failure to identify specific substrates that may be targets for an esterase under study. The availability of naphthyl esters and azo dyes containing ester linkages, coupled with histochemical staining techniques that permitted the visualization of hydrolytic activities following electrophoretic separations, led to classifications according to substrate preference. However, the early broad classification of esterases in vertebrate plasma into three types by Augustinsson (1961)—carboxyl esterases (EC 3.1.1.1), aryl esterases (EC 3.1.1.2), and cholinesterases (EC 3.1.1.8)—must be viewed within the context of overlapping activities.