Browsing Center for Research in Reproduction and Contraception by Subject "Dose-Response Relationship, Drug"
Now showing items 1-20 of 20
-
A clinical trial of injectable testosterone undecanoate as a potential male contraceptive in normal Chinese men
(Endocrine Society, 1999-10)This is a pilot dose-finding study of spermatogenic suppression using testosterone undecanoate (TU) injections alone in normal Chinese men. Thirty-two healthy men were recruited. Volunteers underwent ... -
The direct pituitary effect of testosterone to inhibit gonadotropin secretion in men is partially mediated by aromatization to estradiol
(American Society of Andrology, 1994-01)In men, administration of exogenous testosterone (T) exerts direct negative feedback effects at the pituitary as well as at the hypothalamic level. This study was undertaken to determine whether T itself ... -
Dose effects of the gonadotropin-releasing hormone antagonist, Nal-Glu, combined with testosterone enanthate on gonadotropin levels in normal men
(Elsevier, 1995-07)OBJECTIVE: To test the hypothesis that over a 4-week treatment period, Nal-Glu GnRH antagonist ([AcD2Nal1, D4ClPhe2, D3Pal3, Arg5, DGlu6 [AA], DAla10] GnRH) at a dose of 200 micrograms/kg per day SC would ... -
Effects of castration and recombinant human inhibin administration on circulating levels of inhibin and gonadotropins in adult male monkeys
(American Society of Andrology, 1994-03)Inhibin has been suggested to play a role in gonadal feedback regulation of follicle-stimulating hormone (FSH) secretion; however, neither the half-life nor the time course of action of recombinant inhibin ... -
Follistatin decreases activin-stimulated FSH secretion with no effect on GnRH-stimulated FSH secretion in prepubertal male monkeys
(Endocrine Society, 1994-04)Follistatin is an activin-binding glycoprotein that decreases FSH secretion in vitro and in vivo in rats. The mechanism by which follistatin acts is unclear, but it has been suggested that it may bind ... -
Higher testosterone dose impairs sperm suppression induced by a combined androgen-progestin regimen
(American Society of Andrology, 2002-09)In this study we compared the effects of high-dose and low-dose testosterone enanthate (TE) administered with the same dose of cyproterone acetate (CPA). Eighteen men aged 21-45 were treated with CPA 5 mg/day ... -
The importance of luteinizing hormone in the control of inhibin and progesterone secretion by the human corpus luteum
(Endocrine Society, 1989-06)Serum inhibin levels rise markedly during the luteal phase of the human menstrual cycle and are closely correlated with serum progesterone (P) levels, suggesting that the corpus luteum (CL) secretes inhibin. ... -
Intratesticular testosterone concentrations comparable with serum levels are not sufficient to maintain normal sperm production in men receiving a hormonal contraceptive regimen
(American Society of Andrology, 2004-11)Intratesticular testosterone (ITT) is thought to play a key role in the control of spermatogenesis in man but is rarely measured. The purposes of this study were 1) to examine the relationship between ... -
A lower dosage levonorgestrel and testosterone combination effectively suppresses spermatogenesis and circulating gonadotropin levels with fewer metabolic effects than higher dosage combinations
(American Society of Andrology, 1999-05)Studies using exogenous high-dosage testosterone (T) or a combination regimen of physiologic T plus high-dosage levonorgestrel (LNG) administration in normal men have shown that oligoazoospermia (<3 ... -
Male hormonal contraception: effects of injections of testosterone undecanoate and depot medroxyprogesterone acetate at eight-week intervals in chinese men
(Endocrine Society, 2004-05)Surveys indicate that one form of acceptable male hormonal contraception would consist of injections given at 2- to 3-month intervals. This report describes a study of depot medroxyprogesterone acetate (DMPA) ... -
MSY2 and MSY4 bind a conserved sequence in the 3' untranslated region of protamine 1 mRNA in vitro and in vivo
(American Society for Microbiology, 2001-10)Y-box proteins are major constituents of ribonucleoprotein particles (RNPs) which contain translationally silent mRNAs in gametic cells. We have recently shown that a sequence-specific RNA binding activity ... -
Physiological levels of estradiol stimulate plasma high density lipoprotein2 cholesterol levels in normal men
(Endocrine Society, 1994-04)Premenopausal women have a lower risk of coronary artery disease than men or postmenopausal women; estrogens are thought to contribute to this lower risk. Administration of exogenous estrogen to post-menopausal ... -
Prostate-sparing effects in primates of the potent androgen 7alpha-methyl-19-nortestosterone: a potential alternative to testosterone for androgen replacement and male contraception
(Endocrine Society, 1998-12)7alpha-Methyl-19-nortestosterone (MENT) is a potent synthetic androgen that cannot be converted to dihydrotestosterone. In this study we determined the relative androgenic, antigonadotropic, and anabolic ... -
Quantitative and qualitative changes in serum luteinizing hormone after injectable testosterone undecanoate treatment in hypogonadal men
(Blackwell Publishing, 2000-03)AIM: To clarify the immuno-active LH (i-LH) and bioactive LH (b-LH) responses and qualitative changes in the circulating LH to testosterone undecanoate (TU) injection. METHODS: Eight men with Klinefelter's ... -
Regulation of luteinizing hormone pulse frequency and amplitude by testosterone in the adult male rat
(Endocrine Society, 1982-12)Our objective was to gain a better understanding of the role of testosterone (T) in regulating the minute to minute dynamics of LH secretion in the adult male rat. To this end, we examined the patterns of ... -
A role for galanin-like peptide in the integration of feeding, body weight regulation, and reproduction in the mouse
(Endocrine Society, 2003-03)Galanin-like peptide (GALP) shares sequence homology with galanin and binds to galanin receptors in vitro. GALP neurons in the arcuate nucleus coexpress leptin receptors, and GALP mRNA expression is up-regulated ... -
Serum bioactive and immunoreactive follicle-stimulating hormone levels and the response to clomiphene in healthy young and elderly men
(Endocrine Society, 1987-06)Testicular function declines with normal aging, while serum immunoreactive LH and FSH levels increase. Since there are reports of an age-related decrease in the ratio of bioactivity to immunoreactivity (B/I ... -
Stimulation of Sertoli cell inhibin secretion by the testicular paracrine factor PModS
(Elsevier, 1989-10)The testicular paracrine factor PModS is produced by peritubular myoid cells under androgen control and modulates Sertoli cell function and differentiation. The observation that luteinizing hormone (LH) ... -
Stimulation of sperm production by human luteinizing hormone in gonadotropin-suppressed normal men
(Endocrine Society, 1984-11)The relative roles of FSH and LH in the control of human spermatogenesis are not well established. We previously reported that supraphysiological doses of hCG can stimulate sperm production in gonadotropin- ... -
Testosterone undecanoate maintains spermatogenic suppression induced by cyproterone acetate plus testosterone undecanoate in normal men
(Endocrine Society, 2003-12)In this study we evaluated whether testosterone undecanoate (TU), alone or combined with low dose cyproterone acetate (CPA), can maintain spermatogenic suppression induced by higher doses of CPA plus TU. ...