The initial phase of GnRH‐stimulated LH release from pituitary cells is independent of calcium entry through voltage‐gated channels

Smith, Colleen E.; Wakefield, I.; King, Judy A.; Naor, Zvi; Millar, Robert P.; Davidson, James S.

doi:10.1016/0014-5793(87)81167-5

Cited by 33 publications

(14 citation statements)

References 19 publications

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“…However, the following should be noted. LH release has been shown to be partially or completely dependent on Ca2+ influx (2,19). This Ca2+ influx apparently involves L-type channels (19,28), although there is also some disagreement on this point (2,29).…”

Section: Methodsmentioning

confidence: 99%

“…LH release has been shown to be partially or completely dependent on Ca2+ influx (2,19). This Ca2+ influx apparently involves L-type channels (19,28), although there is also some disagreement on this point (2,29). However, recent studies, which monitored LH release on a relatively rapid time base, indicated that L-channel blockers did not block an initial spike of LH release but did block subsequent release over an extended time course (19).…”

Section: Methodsmentioning

confidence: 99%

“…There is no consensus as to the role ofGnRH-induced inositolphospholipid breakdown in this process. Thus, evidence for (19) and against (2,27) the importance of intracellular Ca2+ mobilization has been presented. Space does not allow a thorough discussion of the literature relating to this important point.…”

Section: Methodsmentioning

confidence: 99%

“…This Ca2+ influx apparently involves L-type channels (19,28), although there is also some disagreement on this point (2,29). However, recent studies, which monitored LH release on a relatively rapid time base, indicated that L-channel blockers did not block an initial spike of LH release but did block subsequent release over an extended time course (19). The nitrendipine-sensitive and -insensitive portions of LH release reported in that study exhibit a close temporal correlation with the spike and secondary rise phases of the Ca2" transients reported here.…”

Section: Methodsmentioning

confidence: 99%

“…6) (2). However, the precise source of the Ca2-+ involved in this response is somewhat controversial (2,18,19 (15,20).…”

Section: Methodsmentioning

confidence: 99%

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Gonadotropin-releasing hormone-induced Ca2+ transients in single identified gonadotropes require both intracellular Ca2+ mobilization and Ca2+ influx.

Shangold

Murphy

Miller

1988

Proc. Natl. Acad. Sci. U.S.A.

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We examIned the effects of gonadotropinreleasing hormone (GnRH) (10). We now report the use of these techniques to show that GnRH produces Ca2" transients in identified gonadotropes with a very characteristic and complex time course. The role of these transients in the control of gonadotropin release is discussed. MATERIALS AND METHODSCell Culture. Female 35-day-old Sprague-Dawley rats were decapitated, their pituitaries were removed, and adenohypophyses were dissected from neurohypophyses. Anterior pituitaries were then enzymatically dispersed for 20 min with 0.25% trypsin (bovine, type XII-S, Sigma) in a metabolic shaker at 370C. Cells were then filtered through organza cloth (Tetko, Elmsford, NY), diluted to 50 ml in medium 199 with Hanks' salts and L-glutamine (GIBCO), and centrifuged at 350 x g for 10 min. The supernatant was removed, and cells were resuspended by trituration through a Pasteur pipette in 5 ml ofmedium and then were plated on sterile, poly(L-lysine)-coated (10 ,ug/ml, Sigma) etched-grid coverslips (Bellco). The cell density was z'2.5 x 105 cells per coverslip. The cell yield was z4 x 105 cells per rat. Cells were incubated for 2 days in 60-mm Falcon culture dishes, with medium 199 containing 10% (vol/vol) heat-inactivated horse serum (GIBCO) and 2.5% (vol/vol) fetal bovine serum (GIBCO) and supplemented with penicillin (5 units/ml) and streptomycin (50 pg/ml), in a 5% C02/95% air atmosphere in a water-jacketed incubator at 370C.Identification of Isolated Gonadotropes. Sheep erythrocytes (Colorado Serum, Denver) were washed four times in 0.9o NaCl and conjugated to protein A (0.5 mg/ml, Sigma) with CrCl2 (0.2 mg/ml). After further washing, cells were then mixed with LH antiserum (1:5), guinea pig complement (1:10, GIBCO), and GnRH (100 nM, Peninsula Laboratories, San Carlos, CA).

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…6) (2). However, the precise source of the Ca2-+ involved in this response is somewhat controversial (2,18,19 (15,20).…”

Section: Methodsmentioning

confidence: 99%

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Gonadotropin-releasing hormone-induced Ca2+ transients in single identified gonadotropes require both intracellular Ca2+ mobilization and Ca2+ influx.

Shangold

Murphy

Miller

1988

Proc. Natl. Acad. Sci. U.S.A.

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Signal transduction of the gonadotropin releasing hormone (GnRH) receptor: Cross-talk of calcium, protein kinase C (PKC), and arachidonic acid

et al. 1995

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1. The decapeptide neurohormone gonadotropin releasing hormone (GnRH) is the first key hormone of the reproductive system. Produced in the hypothalamus, GnRH is released in a pulsatile manner into the hypophysial portal system to reach the anterior pituitary and stimulates the release and synthesis of the gonadotropin hormones LH and FSH. GnRH, a Ca2+ mobilizing ligand, binds to its respective binding protein, which is a member of the seven transmembrane domain receptor family and activates a G-protein (Gq). 2. The alpha subunit of Gq triggers enhanced phosphoinositide turnover and the elevation of multiple second messengers required for gonadotropin release and biosynthesis. 3. The messenger molecules IP3, diacylglycerol, Ca2+, protein kinase C, arachidonic acid and leukotriene C4 cross-talk in a complex networks of signaling, culminating in gonadotropin release and gene expression.

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Calcium mobilization and influx during the biphasic cytosolic calcium and secretory responses in agonist-stimulated pituitary gonadotrophs

Izumi

Stojilković

Catt

1989

Archives of Biochemistry and Biophysics

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The initial phase of GnRH‐stimulated LH release from pituitary cells is independent of calcium entry through voltage‐gated channels

Cited by 33 publications

References 19 publications

Gonadotropin-releasing hormone-induced Ca2+ transients in single identified gonadotropes require both intracellular Ca2+ mobilization and Ca2+ influx.

Gonadotropin-releasing hormone-induced Ca2+ transients in single identified gonadotropes require both intracellular Ca2+ mobilization and Ca2+ influx.

Signal transduction of the gonadotropin releasing hormone (GnRH) receptor: Cross-talk of calcium, protein kinase C (PKC), and arachidonic acid

Calcium mobilization and influx during the biphasic cytosolic calcium and secretory responses in agonist-stimulated pituitary gonadotrophs

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