Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sex hormone-binding globulin (SHBG), percent free estradiol (E2), the fraction of E2 bound to SHBG, and total E2 were measured in the serum and follicular fluid of 12 women (25 follicles) who had received gonadotropin stimulation in an in vitro fertilization program. The women were classified as high or low responders based on peak serum E2 levels (high responders: peak E2, greater than 1500 pg/ml; low responders: peak E2, less than 1000 pg/ml). During treatment, serum levels of SHBG increased in high responders from 55 +/- 8.8 (+/- SEM) to 96 +/- 16 nM (P less than 0.01), but did not change in low responders. SHBG was more concentrated in follicular fluids from high responders (142 +/- 12.5 nM) than in those from low responders (44.4 +/- 5.8 nM). A positive correlation was found between serum and follicular fluid levels of SHBG (r = 0.873; P less than 0.01). In follicular fluid, total E2 levels, which varied from 100-2650 ng/ml, correlated (r = 0.790; P less than 0.01) closely with SHBG levels. The percent free E2 averaged 5.9% (range, 4-10.6%) in follicular fluid compared to 1.8% (range, 1.5-2.1%) in serum. An inverse correlation (r = -0.661; P less than 0.01) was found between total E2 concentrations and percent free E2 in follicular fluid. The relationship between serum and follicular fluid levels of SHBG suggests that SHBG in follicles arises from the circulation. Although SHBG is present in follicular fluid in amounts similar to those in serum, the large quantities of E2 in preovulatory follicules exceed the binding capacity for SHBG, and the majority of E2 appears to be bound to albumin. Hence, it seems unlikely that SHBG in follicular fluid regulates estrogen action in ovarian target cells.
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PMID:Total estradiol, free estradiol, sex hormone-binding globulin, and the fraction of estradiol bound to sex hormone-binding globulin in human follicular fluid. 309 20

Available androgen binding to soluble proteins from the cytosol of human endometrium was studied using the dextran coated charcoal adsorption method and sucrose density centrifugation analysis. Specific binding of [3H]-5 alpha-dihydrotestosterone ([3H]-DHT) was observed with both methods. The apparent dissociation constant (Kd), for DHT binding is 1.3 +/- 0.2 (SEM) nM and the binding capacity 177 +/- 42 (SEM) fmol/mg protein. Sucrose density ultracentrifugation identifies specific [3H]-DHT binding that sediments at 4S and 8S. The stability of the androgen receptor in human endometrium is increased by the addition of 10% glycerol to the homogenization buffer. The addition of trypsin or pronase and heating at 60 degrees C reduces specific binding which demonstrates that the specific [3H]-DHT binder is a protein. The uptake of [3H] DHT in endometrial tissue minces indicated that 20% of the bound radioactivity was nuclear. Steroid specificity suggests that the binding protein from the uterus is specific for androgens. These observations indicate that androgen binding protein in the human uterus has the characteristics of the androgen receptor.
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PMID:The androgen receptor of the human endometrium. 358 78

The annual reproductive cycle of the male little brown bat, in contrast to seasonal reproductive patterns of other mammals, is differentiated by an asynchronous recrudescence of the testis and the accessory reproductive glands. Spermatogenesis occurs during the summer, whereas fully stimulated accessory organs, stored epididymal spermatozoa, and sexual behavior are expressed later during a mating period that extends, albeit interrupted by hibernation, from late summer until early spring. To investigate whether changes in high affinity androgen-binding activity in the circulation are related to the delayed renewal of the accessory organs, plasma sex steroid-binding protein (SBP) and total testosterone (T) levels were measured throughout the year. From these data and determinations of association constants for T binding to SBP and albumin at both hibernating (4 degrees C) and active (40 degrees C) temperatures, estimates of the unbound ("free") and albumin-bound T fractions were made and correlated with changes in the accessory reproductive organs. Plasma SBP concentrations (mean +/- SEM) exhibited wide seasonal fluctuations: they were baseline in May (10 +/- 2 nM) following spring arousal, increased dramatically in June (184 +/- 24 nM), and reached peak levels in early July (262 +/- 29 nM), where they remained until August. In late August they began to fall (104 +/- 23 nM) and then returned to baseline during the hibernation period (October-April). Although total T levels were also elevated in June, it appeared that the unbound ("free") and the unbound plus albumin-bound T fractions did not increase until late July. Since the accessory gland weights did not begin to increase until late July as well, it was concluded that increases in the unbound and albumin-bound T fractions may be an important factor in the recrudescence of the accessories and that increased SBP activity in early summer may play a role in the regression and delayed renewal of these organs. However, what factor(s) maintain the accessory glands, epididymal spermatozoa, and sexual behavior during the breeding and hibernation periods when all T fractions were low are, as yet, undetermined.
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PMID:Annual variations in plasma sex steroid-binding protein and testosterone concentrations in the adult male little brown bat: relation to the asynchronous recrudescence of the testis and accessory reproductive organs. 407 6

Sex hormone-binding globulin (SHBG), 17 beta-estradiol (E2), testosterone (T), 5 alpha-dihydrotestosterone (DHT), T4, and T3 were measured in prepubertal (age, 1--8 yr; n = 44; group I) and pubertal (age, 9--16 yr; n= 56; group II) girls. The main results were as follows. 1) In group I, a higher mean (+/- SEM) value for SHBG was found (73.5 +/- 2.82 nmol/1) compared to that in Group II (56.8 +/- 3.37; P less than 0.001). 2) Despite a significant increase of the androgens T and DHT with age in group I (rT.age = 0.578; rDHT.age = 0.544; P less than 0.01 for each), no significant alteration of SHBG with age was present. 3) In group II, a significant decrease of SHBG with age occurred (rSHBG.age = -0.438; P less than 0.35) along with the expected increases of E2 (rE2.age = 0.691; P less than 0.001), T (rT.age = 0.765; P less than 0.001), and DHT (rDHT.age = 0.712; P less than 0.001). 4) The analysis of the data by partial correlation coefficients supports the suggested role for androgens in the decline of SHBG during puberty in girls, whereas correlations of SHBG with E2 or the thyroid hormones were insignificant.
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PMID:Interrelationships between sex hormone-binding globulin and 17 beta-estradiol, testosterone, 5 alpha-dihydrotestosterone, thyroxine, and triiodothyronine in prepubertal and pubertal girls. 718 24