Browsing Research in Reproduction and Contraception, Center for by Title
Now showing items 28-47 of 220
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A comparison of the suppressive effects of testosterone and a potent new gonadotropin-releasing hormone antagonist on gonadotropin and inhibin levels in normal men
(Endocrine Society, 1989-07)GnRH antagonists have been developed in large part because of their potential use as contraceptive agents, particularly in men. Specifically, it was hoped that GnRH antagonists combined with testosterone (T) ... -
Corpus luteum insufficiency induced by a rapid gonadotropin-releasing hormone-induced gonadotropin secretion pattern in the follicular phase
(Endocrine Society, 1987-09)The pulse frequency of LH and FSH (and by inference, GnRH) is a major determinant of the relative baseline plasma levels of LH and FSH. Luteal phase deficiency has been reported to be associated with increased ... -
The corpus luteum: determinants of progesterone secretion in the normal menstrual cycle
(Elsevier, 1988-05)Fourteen normal volunteers were studied during one menstrual cycle. Follicular development, the luteinizing hormone (LH) surge, and the relationship between LH and progesterone secretion in the luteal phase ... -
Daily testosterone and gonadotropin levels are similar in azoospermic and nonazoospermic normal men administered weekly testosterone: implications for male contraceptive development
(American Society of Andrology, 2001-11)Weekly intramuscular administration of testosterone esters such as testosterone enanthate (TE) suppresses gonadotropins and spermatogenesis and has been studied as a male contraceptive. For unknown reasons, ... -
Decreased serum inhibin levels in normal elderly men: evidence for a decline in Sertoli cell function with aging
(Endocrine Society, 1988-09)Compared to young men, normal elderly men have decreased sperm production despite elevated serum gonadotropin levels. To determine whether the seminiferous tubule defect in elderly men includes decreased ... -
Desogestrel plus testosterone effectively suppresses spermatogenesis but also causes modest weight gain and high-density lipoprotein suppression
(Elsevier, 2000-10)OBJECTIVE: To test the hypothesis that oral desogestrel (DSG) plus testosterone would uniformly and rapidly suppress sperm concentrations in young men as effectively as levonorgestrel (LNG) plus testosterone ... -
Differential control of luteinizing hormone and follicle-stimulating hormone secretion by luteinizing hormone-releasing hormone pulse frequency in man
(Endocrine Society, 1987-04)To test the hypothesis that the frequency of pulsatile LHRH stimulation can differentially control LH and FSH secretion in man, we administered low doses of LHRH in pulsatile fashion in several different ... -
Differential patterns of Fos induction in the hypothalamus of the rat following central injections of galanin-like peptide and galanin
(Endocrine Society, 2003-04)Galanin and its newly discovered relative galanin-like peptide (GALP) are neuropeptides that are implicated in the neuroendocrine regulation of body weight and reproduction. GALP has been shown to bind in ... -
Differential regulation of KiSS-1 mRNA expression by sex steroids in the brain of the male mouse
(Endocrine Society, 2005-07)Kisspeptins are products of the Kiss1 gene, which bind to GPR54, a G protein-coupled receptor. Kisspeptins and GPR54 have been implicated in the neuroendocrine regulation of GnRH secretion. To test the ... -
Diminished luteinizing hormone pulse frequency and amplitude with aging in the male rat
(Endocrine Society, 1983-03)Aging in the male rat is associated with a reduction in circulating testosterone levels. One possible cause of this decline is an age-related alteration of central nervous system-mediated LH secretion. To ... -
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 ... -
Distribution and regulation of galanin receptor 1 messenger RNA in the forebrain of wild type and galanin-transgenic mice
(Endocrine Society, 2003)To learn more about molecular alterations in the brain that occur as a consequence of either the chronic excess or absence of peptide neurotransmitters, we examined the impact of genetically manipulating the ... -
Distribution and regulation of galanin-like peptide (GALP) in the hypothalamus of the mouse
(Endocrine Society, 2001-12)Galanin-like peptide (GALP) is a newly discovered molecule whose expression in the brain is confined to the arcuate nucleus and median eminence. In the rat, cellular levels of GALP mRNA are reduced by fasting ... -
Distribution of galanin messenger RNA-expressing cells in murine brain and their regulation by leptin in regions of the hypothalamus
(Elsevier, 2001)Galanin is widely distributed throughout the mammalian brain and has been implicated in the regulation of food intake, metabolism and reproduction-functions that are also thought to be under the control of ... -
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 ... -
A double-stranded RNA binding protein required for activation of repressed messages in mammalian germ cells
(Nature Publishing Group, 1999-06)Chromatin packaging in mammalian spermatozoa requires an ordered replacement of the somatic histones by two classes of spermatid-specific basic proteins, the transition proteins and the protamines. Temporal ... -
Ectopic galanin expression and normal galanin receptor 2 and galanin receptor 3 mRNA levels in the forebrain of galanin transgenic mice
(Elsevier, 2005)The functional interactions of the neuropeptide galanin (GAL) occur through its binding to three G protein-coupled receptor subtypes: galanin receptor (GALR) 1, GALR2 and GALR3. Previously, we demonstrated ... -
Effect of CGS 20267 on ovarian aromatase and gonadotropin levels in the rat
(Springer Verlag, 1998-03)Aromatase catalyzes the rate limiting step that converts androgens to estrogens. Postmenopausal women with hormone dependent breast cancer respond to first generation aromatase inhibitors such as aminoglutethimide ... -
Effect of fasting, refeeding, and dietary fat restriction on plasma leptin levels
(Endocrine Society, 1997-02)The factors responsible for the variability in plasma leptin levels observed among individuals with similar body compositions remain unclear. To examine the impact of dietary variables, we compared the changes ...