Gonadotropin-releasing hormone (GnRH) acts at gonadotropes to direct the synthesis of the gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). The frequency of GnRH pulses determines the pattern of gonadotropin synthesis. Several hypotheses for how the gonadotrope decodes GnRH frequency to regulate gonadotropin subunit genes differentially have been proposed. However...

melanocortin- 4 receptor (mc4r) and agouti- related peptide (agrp) are involved in energy homeostasis in rats. according to mc4r and agrp effects on luteinizing hormone (lh) secretion, they may influence the estrous cycle of rats. therefore, the aim of this study was to investigate the expression of mc4r and agrp mrnas at different stages of estrous cycle in the rat’s hypothalamus. the estrous ...

We evaluated the effects of caponization on mRNA levels of gonadotropin-releasing hormone-I (GnRH-I), gonadotropin subunit and other hypothalamic and hypophyseal peptide genes in male chicken. Thirty roosters (25 d) with similar weight were equally divided into the experimental (capons) and control (sham-operated males) groups randomly. Caponization was performed at 28 days of age and birds wer...

Rapid effects of social interactions on transient changes in hormonal levels are known in a wide variety of vertebrate taxa, ranging from fish to humans. Although these responses are mediated by the brain, neurochemical pathways that translate social signals into reproductive physiological changes are unclear. In this study, we analyzed how a female presence modifies synthesis and/or release of...

To better understand the molecular mechanism(s) underlying egg-laying in Sichuan white geese, the profiles of genes in the pituitary gland were investigated during the prelaying and laying periods. Total RNA was extracted from the pituitary glands of geese during prelaying or laying periods and cDNA was generated. After sequencing and annotation, 54 upregulated and 84 downregulated genes were o...

The human gonadotropin-releasing hormone (GnRH) precursor consists of the GnRH sequence followed by a 59-amino acid carboxyl-terminal extension. A 56-amino acid peptide within this extension has been shown to stimulate gonadotropin release, and this activity has been localized to its amino-terminal region. A series of seven overlapping peptide fragments corresponding to the first 24 amino acids...

Background: This retrospective study evaluated the effect of profound pituitary suppression with oral contraceptive pill (OCP) pretreatment in gonadotropin-releasing hormone (GnRH) antagonist cycles stimulated with recombinant follicle stimulating hormone plus highly purified human menopausal gonadotropin. Methods: The analysis included women aged 20-46 years (N=318) who utilized OCP pretreatme...

Although it is well established that the secretory activity of the corpus luteum absolutely depends on the presence of pituitary-derived luteinizing hormone (LH), it is unknown why the life span of the corpus luteum is extended during early pregnancy by the placental production of chorionic gonadotropin (CG) but regresses in the presence of LH despite the fact that CG and LH have similar action...