These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: Cyclic AMP indirectly mediates the extracellular Ca2+-independent release of LH.
    Author: Bourne GA.
    Journal: Mol Cell Endocrinol; 1988 Aug; 58(2-3):155-60. PubMed ID: 2850245.
    Abstract:
    This study was undertaken to determine whether cyclic AMP mediates the extracellular Ca2+-independent component of luteinizing hormone (LH) release. Gonadotropin releasing hormone (GnRH) increased cAMP production in female pituitaries incubated in Ca2+-free medium containing 3-isobutyl-1-methylxanthine (IBMX), but was ineffective in male pituitaries. The increases in female pituitaries were inhibited by flufenamate (flu). GnRH-stimulated LH secretion from male pituitaries was completely inhibited in Ca2+-free medium, whereas only a partial inhibition was obtained from female pituitaries, a response prevented by cycloheximide. Infusions of flu completely inhibited the extracellular Ca2+-independent release of LH, while dibutyryl cAMP (dbcAMP) partially restored this component of LH secretion. The dbcAMP-restored response was dependent upon protein synthesis. These results suggest that (i) the extracellular Ca2+-independent component of LH release is indirectly mediated by cAMP through the stimulation of de novo protein synthesis, and (ii) extracellular Ca2+ is required for the activation of adenylate cyclase in male but not in female gonadotrophs.
    [Abstract] [Full Text] [Related] [New Search]