HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chang, J. P. Articles by Catt, K. J. Search for Related Content PubMed PubMed Citation Articles by Chang, J. P. Articles by Catt, K. J. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 261, Issue 20, 9105-9108, Jul, 1986

Participation of voltage-dependent calcium channels in the action of gonadotropin-releasing hormone

JP Chang, EE McCoy, J Graeter, K Tasaka and KJ Catt

The roles of calcium ions and voltage-sensitive calcium channels in gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone (LH) release were investigated in rat anterior pituitary cells. The calcium ionophores A23187 and ionomycin stimulated LH release from cultured pituitary cells, in which ionomycin (5 X 10(-5) M) was as effective as a maximal concentration of GnRH (10(-8) M). In addition, a concentration of the calcium channel agonist methyl 1,4-dihydro-2,6- dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine- 5-carboxylate (BK 8644) (10(-8) M), which did not alter basal LH release, potentiated the ability of submaximal (10(-10) and 10(-9) M) doses of GnRH to increase LH secretion. Furthermore, concentrations of the calcium channel antagonist nitrendipine (10(-8)-10(-5) M) that did not alter basal LH release, inhibited GnRH-stimulated LH secretion by 30-40%. Nitrendipine (10(-8) M) also blocked the potentiation of GnRH-induced LH secretion by BK 8644. During column perifusion of pituitary cells, 10(-8) M nitrendipine reduced the LH response to a 2-min pulse of 10(- 8) M GnRH by about 40%. In Quin-2-loaded pituitary cells, supramaximal doses (10(-6) M) of a potent GnRH agonist rapidly elevated cytoplasmic Ca2+ by 50-100 nM. Concomitant treatment with nitrendipine decreased the GnRH agonist-induced Ca2+ signal by 40-60%. These results indicate that increases in intracellular Ca2+ via voltage-sensitive calcium channels partially reproduce GnRH action, and also that GnRH causes activation of such channels. However, the increase in cytoplasmic Ca2+ concentration during GnRH action must originate in part from mobilization of internal Ca2+ stores, and its relatively small magnitude may be consistent with the concomitant activation of protein kinase C as an intermediate step in GnRH action.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. VANECEK Cellular Mechanisms of Melatonin Action Physiol Rev, July 1, 1998; 78(3): 687 - 721. [Abstract] [Full Text] [PDF]

				A Tse and B Hille GnRH-induced Ca2+ oscillations and rhythmic hyperpolarizations of pituitary gonadotropes Science, January 24, 1992; 255(5043): 462 - 464. [Abstract] [PDF]