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The initial phase of GnRH‐stimulated LH release from pituitary cells is independent of calcium entry through voltage‐gated channels
Author(s) -
Smith Colleen E.,
Wakefield I.,
King Judy A.,
Naor Z.,
Millar R.P.,
Davidson J.S.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81167-5
Subject(s) - endocrinology , medicine , extracellular , nifedipine , gonadotropin releasing hormone , chemistry , stimulation , luteinizing hormone , intracellular , gonadotropin , calcium , voltage dependent calcium channel , channel blocker , biophysics , hormone , biology , biochemistry
Kinetic studies on gonadotropin‐releasing hormone (GnRH)‐stimulated luteinizing hormone (LH) release were undertaken using rat and chicken pituitary cell cultures. In response to continuous GnRH stimulation, a biphasic pattern of LH release was demonstrated. The two phases showed different susceptibility to the voltage‐gated Ca 2+ channel blockers D600 and nifedipine. The first (transient) phase of LH release was unaffected by the Ca 2+ channel blockers whereas the second (sustained) phase was inhibited by both drugs. These results indicate that the initial phase of LH release is independent of Ca 2+ entry through voltage‐gated Ca 2+ channels and may depend on mobilisation of intracellular Ca 2+ or entry of extracellular Ca 2+ through another mechanism.