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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Binding and physico-chemical properties of sex steroid-binding protein (SBP) from blood serum and those of estrogen-binding components from liver cytosol of pubertal male and female species of clawed frog Xenopus laevis were studied. It was shown that SBP from both sex species of X. laevis specifically binds estradiol (E2) (Ka=5 . 10(6) M-1). Concentration of SBP binding sites for E2 is 7 . 10(-12) mole per mg of protein. Testosterone 5alpha-dihydrotestosterone and E2 effectively compete with [3H]-E2 for SBP binding sites. Hexestrol, progesterone and corticosterone are weak competitors; estrone and E2-17-hemisuccinate do not compete at all. The Strokes radius of SBP is 4.4 nm; sedimentation coefficient is 4.6S. Molecular weight of SBP is 88000; f/f0 is 1.5 SBP from male frog sera has been purified 8.6-fold with 13% yield. Gel-filtration of [3H]-E2 complexes with liver cytosol proteins shows that the livers of male and female frog X. laevis consol proteins shows that the livers of male and female frog X. laevis contain very low amounts of macromolecular component, which specifically binds E2; this component differs from serum SBP in size and in hormonal specificity. It is assumed that this component is a receptor for estrogens.
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PMID:[Properties of sex steroid-binding protein from Xenopus laevis blood serum and detection of an estradiol-binding component in frog liver cytosol which differs from sex steroid-binding protein]. 21 28

Protamine sulfate precipitation is used for the selective and quantitative assay of equilibrium binding constants. The association constant of dihydrotestosterone is 1 X 10(9)1/mole and the number of binding sites is 11.500/cell. The affinity of testosterone is slightly lower than that of dihydrotestosterone, whereas some synthetic androgens have a higher affinity in accordance with their biological activity. Estradiol, progesterone and antiandrogens can displace dihydrotestosterone from its receptor. The occupied cytosolic and nuclear binding sites can be measured by radioimmunoassay. After castration, the nuclear hormone-receptor complexes disappear with a half-life of 3 hours. The cytosol receptor decreases steadily between the first and the fourth day after castration, then increases spontaneously. Testosterone seems to inhibit the degradation and also to stimulate the synthesis of its own receptor. Radioautography shows that the receptor is present only in the epithelial cells.
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PMID:[Androgen binding proteins in the rat prostate: methodological problems and regulation (author's transl)]. 100 14

Testosterone-3-O-carboxymethyl-oxime derivative was synthetized and coupled to bovine serum albumin (BSA). The T-3-CMO-BSA conjugate homogenized with Freund's adjuvant used as immunogen was injected multiple sites in rabbits. The antisera collected were characterized in a radioimmunological system, separation with dextran-charcoal using 125I-Testosterone as tracer. The antibody titres varied from one animal to another. The titre of anti-T serum selected for RIA was 1: 10(4)-1: 2 X 10(4) (initial dilution). All anti-T sera 100 percent crossreacted with 5 alpha-dihydrotestosterone but nonsignificant interference was observed with other C19, C21 and C18 steroids. The affinity constant of the selected anti-T serum was in the range 1.4-1.9 X 10(9) litres/mole. The data so far published on the antisera toward testosterone are reviewed. We conclude that the selected anti-T-3-CMO-BSA serum may provide assays for testosterone with potential for clinical applications.
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PMID:The development of a radioimmunoassay system for testosterone (T) and dihydrotestosterone (DHT). Part 2. The preparation of antisera to T. 210 70

Cultured seminal vesicle cells of Gobius niger L., precultured for about 15 days, are tested for their Testosterone-binding capacity. This whole cell system shows a specific binding of the androgen, reaching saturation in the presence of increasing amounts of ligand and the Scatchard Plot indicates a good affinity (KD = 4.4 x 10(-9) M), involving a number of sites of 5.06 x 10(-15) mole/culture. The possible existence of a second binding-site population with lower affinity and greater number of sites remains to be demonstrated. At 18 degrees C, the time course shows a maximal binding after about 60 min. of incubation, followed by a rapid decline at 90 min. The competition experiments involving estradiol, 11-keto- and 11-hydroxytestosterone indicate an effective if not total specificity to these steroids. The cross-reaction percentages at the 50% binding level are respectively 10.9, 8.5, 4.02%. Ovine Prolactin treatment of the cultures for 6 days before the binding experiment significantly improves the specific binding level of testosterone if compared to the controls (p .019, p .005). This result indicates that the Prolactin-Testosterone synergistic data already obtained on the seminal vesicles of Siluridae and Gobiidae is explained by a direct effect of the Prolactin on the androgen receptor level in the seminal vesicle cell.
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PMID:[Prolactin and specific binding of testosterone in cultured cells of the seminal vesicle of Gobius niger L]. 251 69

Testosterone binding to plasma proteins has been analyzed in the viviparous lizard by electrophoresis at steady state conditions and by equilibrium dialysis. Two binding systems are involved. The first system (S1) binds estradiol and testosterone, it is Sex Binding Protein like. The second one binds testosterone and dihydrotestosterone; the mains competitors are C21 steroids: progesterone and cortisone; estradiol doesn't perturb the equilibrium; this system is Corticosteroid Binding Globulin like. Androstenedione doesn't seem to be bound by these two systems. The high affinity (KA 4 degrees C = 1.28 X 10(8) M-1) and the high capacity (N = 1,18 X 10(-5) mole/litre) suggest that it is the second system that supports the main transport, buffer, reservoir role in the blood of viviparous lizard.
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PMID:[Binding of testosterone to plasma proteins in the viviparous male lizard]. 621 73

The blind mole rat is a seasonally breeding fossorial rodent that is perceptionally blind. This study examines the effect of photoperiod on the morphology and histology of the male mole rat reproductive system, three groups of male mole rats were maintained in the laboratory under short day (SD) conditions (9L: 15D); long day (LD) conditions (15L:9D); and constant darkness (CD), and compared to animals trapped in the field (FL). It was found that the field animals revealed higher testes and prostate gland weights, higher prostate tubuli volume (v*) and lower testes tubuli volume (v*) compared to the other three groups. Distribution of the tubuli in the testes (Vv) was low in the FL group compared to the SD and LD groups but still higher than in the CD group. Distribution of lumen in the testes (Vv) was higher in the CD group in comparison to the other three groups. Distribution of interstitial tissue in the testes (Vv) was higher in the FL group than in the other three groups. Electrolytes and elements secreted from the prostate gland did not differ among the four groups. In the FL group distribution of the tubuli (Vv) in the prostate gland was low and lumen ratio (Vv) was high compared to the other three groups. Distribution of connective tissue in the prostate gland did not differ among all four groups. Testosterone levels and total sperm count was highest in the FL group. Sperm production was noted in all groups; however spermatid and spermatozoa cell production was higher in the FL group. This study shows that photoperiod could be important in initiating timing in the breeding season but that certain other conditions which are absent in the laboratory appear to be responsible for successful breeding in the field.
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PMID:Effect of photoperiod variation on testes and accessory sex organs in the male blind mole rat Spalax ehrenbergi. 1099 17