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Biochemistry Nov 2003Binding studies of the interaction of immobilized 1alpha- and 17alpha-aminoalkyl derivatives of 5alpha-dihydrotestosterone (DHT) with purified N-deglycosylated... (Comparative Study)
Comparative Study
Binding studies of the interaction of immobilized 1alpha- and 17alpha-aminoalkyl derivatives of 5alpha-dihydrotestosterone (DHT) with purified N-deglycosylated homodimeric human sex hormone-binding globulin (SHBG) were performed using a surface plasmon resonance biosensor. These 1alpha- and 17alpha-derivatives with spacers of appropriate lengths between the amine function and the steroid ring skeleton enabled privileged, sterically undisturbed, interactions of either the 17- or 3-characteristic functional groups of DHT with SHBG. The association constants (K(a)1) for the binding of these immobilized DHT derivatives to the first binding site of SHBG, determined by SPR measurements, were 0.16 x 10(7) M(-1) for 17alpha-aminopropyl-17beta-hydroxy-5alpha-androstan-3-one (1), 1.64 x 10(7) M(-1) for 17alpha-aminocaproyl-17beta-hydroxy-5alpha-androstan-3-one (2), and 1.2 x 10(8) M(-1) for 1alpha-aminohexyl-17beta-hydroxy-5alpha-androstan-3-one (3). These values were compared with global K(a) data for the corresponding nonimmobilized DHT derivatives from equilibrium measurements using competitions with a tritiated testosterone tracer: the K(a) values were 1.25 x 10(7) M(-1) for 1, 1.50 x 10(7) M(-1) for 2, and 140 x 10(7) M(-1) for 3, confirming a remarkably high binding affinity of this latter compound for SHBG. A global fitting analysis of the biosensor data revealed that the interaction of the three immobilized steroids with SHBG was best described by a kinetic model assuming two structurally independent binding sites. This hypothesis of a bivalent binding model was also directly suggested by a dual fluorescent signal observed by the flow cytometry analysis of SHBG immobilized as a hybrid complex binding simultaneously two 1alpha-aminohexyl DHT ligands, one formed by 3, covalently coupled to phycoerythrin-labeled latex microspheres, and the other by the same DHT derivative, coupled to a fluorescein derivative (4).
Topics: Binding Sites; Biosensing Techniques; Dihydrotestosterone; Dimerization; Flow Cytometry; Humans; Kinetics; Latex; Microspheres; Models, Chemical; Protein Binding; Sex Hormone-Binding Globulin; Surface Plasmon Resonance; Testosterone; Thermodynamics
PubMed: 14622020
DOI: 10.1021/bi035269k -
Endocrinology Jan 1976The concentration of testosterone (T) and 5alpha-dihydrotestosterone (DHT) in plasma, seminal fluid, and epididymis of male Wistar rats have been determined by...
The concentration of testosterone (T) and 5alpha-dihydrotestosterone (DHT) in plasma, seminal fluid, and epididymis of male Wistar rats have been determined by radioimmunoassay. The DHT/T ratio rose from 0.1 in blood to 1 in testicular fluid and 4 in epididymal fluid. This ratio is 2 in tissues of "caput" epididymis and 1 in "cauda" epididymis. These data indicate a transformation of T to DHT in the epididymal tissue, particularly at the "caput" level.
Topics: Animals; Dihydrotestosterone; Epididymis; Male; Rats; Semen; Testosterone
PubMed: 1248440
DOI: 10.1210/endo-98-1-111 -
British Medical Journal (Clinical... Jun 1983
Topics: Adult; Dihydrotestosterone; Female; Humans; Premenstrual Syndrome
PubMed: 6407567
DOI: 10.1136/bmj.286.6380.1784-a -
Steroids Nov 2009We developed highly sensitive detection of testosterone (T) and 5alpha-dihydrotestosterone (DHT) by liquid chromatography-electrospray ionization tandem mass...
Development of highly sensitive quantification method for testosterone and dihydrotestosterone in human serum and prostate tissue by liquid chromatography-electrospray ionization tandem mass spectrometry.
We developed highly sensitive detection of testosterone (T) and 5alpha-dihydrotestosterone (DHT) by liquid chromatography-electrospray ionization tandem mass spectrometry using high proton affinitive derivatization of 17beta-hydroxyl group of T and DHT with picolinic acid, mobile phase consisting of MeCN-MeOH-H(2)O-formic acid and conventional octadecylsilica (ODS) column. Purification of the derivatives was carried out using solid-phase extraction with ODS cartridge. By this method, T and DHT were determined simultaneously with limits of quantification (LOQs) of 1 pg/0.2 ml in serum, and T and DHT with LOQs of 0.5 pg and 1 pg/3mg in prostate tissue, respectively, under acceptable assay performance (intra-assay and inter-assay accuracy and precision). The present method provides reliable and reproducible results for quantification of T and DHT in small volumes of serum and prostate samples for diagnosis in prostatic disorders and male climacteric.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Blood Chemical Analysis; Calibration; Chromatography, Liquid; Dihydrotestosterone; Esters; Female; Humans; Linear Models; Male; Middle Aged; Picolinic Acids; Prostate; Specimen Handling; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Testosterone; Time Factors; Young Adult
PubMed: 19576916
DOI: 10.1016/j.steroids.2009.06.007 -
Steroids Oct 1974
Comparative Study
Topics: Adult; Androstanes; Animals; Binding Sites; Carbodiimides; Cattle; Cross Reactions; Dihydrotestosterone; Evaluation Studies as Topic; Female; Fourier Analysis; Humans; Immune Sera; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Methods; Protein Binding; Rabbits; Radioimmunoassay; Serum Albumin, Bovine; Spectrophotometry, Ultraviolet; Testosterone; Tritium
PubMed: 4473080
DOI: 10.1016/0039-128x(74)90130-5 -
Analytical Biochemistry Mar 1972
Topics: Acetates; Acylation; Animals; Chemical Phenomena; Chemistry; Chlorine; Chromatography, Gas; Chromatography, Paper; Chromatography, Thin Layer; Dihydrotestosterone; Dogs; Drug Stability; Male; Mathematics; Methods; Prostate; Solvents; Steroids; Testosterone; Tritium
PubMed: 5017667
DOI: 10.1016/0003-2697(72)90394-6 -
Nuclear Medicine and Biology Jan 2001We have synthesized a 18F-labeled androgen, [7alpha-18F]fluoro-17alpha-methyl-5alpha-dihydrotestosterone, in a no-carrier-added radiosynthesis by exchange of 18F-...
We have synthesized a 18F-labeled androgen, [7alpha-18F]fluoro-17alpha-methyl-5alpha-dihydrotestosterone, in a no-carrier-added radiosynthesis by exchange of 18F- (tetrabutylammonium fluoride) with the 7beta-tosyloxy of 17alpha-methyl-5alpha-dihydrotestosterone. The nonradioactive steroid binds with high affinity and specificity to the androgen receptor and binds poorly, if at all, to other steroid receptors and plasma sex hormone binding globulin. The 7alpha-18F-androgen concentrates markedly in the prostate of rats by an androgen receptor-dependent mechanism. It is likely that [7alpha-18F]fluoro-17alpha-methyl-5alpha-dihydrotestosterone will be an excellent positron emission tomography imaging agent for prostate cancer.
Topics: Animals; Dihydrotestosterone; Male; Prostatic Neoplasms; Radionuclide Imaging; Rats; Receptors, Androgen; Tissue Distribution
PubMed: 11182568
DOI: 10.1016/s0969-8051(00)00172-4 -
International Journal of Andrology Dec 2001The primary aim of the present study was to determine the therapeutic dose of subcutaneous levonorgestrel (LNG) to induce azoospermia or severe oligozoospermia (<3 x... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
The primary aim of the present study was to determine the therapeutic dose of subcutaneous levonorgestrel (LNG) to induce azoospermia or severe oligozoospermia (<3 x 10(6)/mL) in normal men requiring contraception. Transdermal 5 alpha-dihydrotestosterone (DHT) was combined to the treatments to maintain peripheral androgen level. Forty-three 21-45-year-old healthy men were enrolled in this phase II randomised and comparative clinical performance study. The subjects were allocated to five groups to receive: (1) transdermal DHT (Andractim(R), Besins Iscovesco, Paris, France) and one subdermal LNG implant (Jadelle, Leiras, Turku, Finland); (2) transdermal DHT and two subdermal LNG implants; (3) transdermal DHT and four subdermal LNG implants; (4) transdermal DHT and oral LNG (Microluton, Schering, Germany); or (5) transdermal DHT only. A total of 27 men completed the suppression phase. None of them reached azoospermia. One subject with oral LNG and transdermal DHT reached <3 million/mL at 5 months of suppression, but not repeatedly. Together 2/27 (7%) subjects, one with oral LNG and DHT and the other with four subdermal LNG implants and DHT reached <5 million/mL temporarily. Altogether 9/27 (33%) subjects reached <20 million/mL. Serum testosterone concentrations (S-T) decreased significantly during the first 3 months of treatment with one, two and four LNG implants and DHT and during the next 3 months S-T remained significantly lower with two or four implants. Serum oestradiol concentrations (S-E(2)) decreased significantly during the first 3 months only with four implants, but at 6 months S-E(2) was lower also in the group with two implants. Serum luteinizing hormone (LH) decreased significantly only with two LNG implants and DHT gel at 5 and 6 months. Serum FSH did not decrease in any of the groups. None of the subjects filled the criteria to continue to the efficacy phase. A total of 16 men discontinued for various reasons. Of the 27 men completing the suppression phase, all have recovered to sperm levels >20 million/mL. There were no changes in blood count, lipid profile, liver function tests, prostate-specific antigen (PSA), sex hormone binding globulin (SHBG), prolactin or cortisol. The mixed antiglobulin reaction (MAR)-IgG, MAR-IgA or tray agglutination test (TAT) did not change during any of the treatments. The present study shows that the LNG implants themselves are well-tolerated by men and safe, and might be suitable for replacing part of the testosterone used as injections to reduce the androgen dose during male hormonal contraception. The DHT gel was considered as quite or very uncomfortable by 66% of the men because of feeling cold during the time it was on the skin, but noncompliance in using the gel was not reported by the men.
Topics: Adult; Contraceptive Agents, Male; Dihydrotestosterone; Drug Implants; Drug Therapy, Combination; Humans; Levonorgestrel; Male
PubMed: 11737418
DOI: 10.1046/j.1365-2605.2001.00319.x -
Molecular and Cellular Endocrinology May 1981These studies were designed to further investigate whether 5 alpha-androstane-3 beta, 17 beta-diol was exerting unique effects on rat prostate acid phosphatase activity...
These studies were designed to further investigate whether 5 alpha-androstane-3 beta, 17 beta-diol was exerting unique effects on rat prostate acid phosphatase activity or could possibly be exerting its actions by a small peripheral conversion to 5 alpha-dihydrotestosterone. Intraperitoneal administration of 5 alpha-dihydrotestosterone in doses of 1 mg, 100 microgram or 50 microgram per day starting 7 days after castration led to the restoration of normal characteristics of acid phosphatase activity. However, when 5 alpha-dihydrotestosterone was given in a dose of only 25 microgram per day starting 7 days after castration, the changes in acid phosphatase activity were indistinguishable from those found when 5 alpha-androstane-3 beta, 17 beta-diol was administered in a dose of 2 mg per day. This suggests that the effects of 5 alpha-androstane-3 beta, 17 beta-diol can be explained by its conversion to small amounts of 5 alpha-dihydrotestosterone.
Topics: Acid Phosphatase; Androstane-3,17-diol; Androstanols; Animals; Castration; Dihydrotestosterone; Male; Prostate; Rats
PubMed: 7239003
DOI: 10.1016/0303-7207(81)90093-9 -
The Journal of Clinical Endocrinology... Dec 1978Tritiated testosterone and [14C]dihydrotestosterone (DHT) were administered by constant iv infusion into five young and five elderly men undergoing diagnostic cardiac...
Tritiated testosterone and [14C]dihydrotestosterone (DHT) were administered by constant iv infusion into five young and five elderly men undergoing diagnostic cardiac catheterization. The radioactivity concentrations of free and conjugated DHT in arterial and hepatic vein blood samples were then determined. The analysis of the 3H:14C ratio of free DHT in arterial and hepatic vein blood showed that in both groups, the 3H:14C ratio of free DHT was the same in arterial and hepatic vein blood, indicating that splanchnic tissue is not the source of blood DHT from testosterone. This is in agreement with data that the transfer constant across the liver ([rho]T-DHT SD) was undetectable. In both young and elderly men, a significant increase of the 3H concentration of DHT glucuronide in hepatic vein blood was observed, indicating that the splanchnic compartment could be the site of production of DHT glucuronide. The 3H:14C ratio of DHT glucuronide was much higher than that of free DHT in both groups, suggesting that DHT glucuronide is derived from the blood testosterone pool, and most of the DHT from testosterone seems to be conjugated before mixing with blood DHT. This study indicates that a large fraction of DHT produced in the liver from testosterone is efficiently conjugated or further metabolized, and this results in the lack of splanchnic production of free DHT in men.
Topics: Adult; Aged; Arteries; Carbon Radioisotopes; Dihydrotestosterone; Hepatic Veins; Humans; Liver; Male; Middle Aged; Testosterone; Tritium
PubMed: 263350
DOI: 10.1210/jcem-47-6-1282