Calmodulin and Ca2+‐ and Calmodulin‐Dependent Protein Kinase in Rat Anterior Pituitary Gland

Yasuyuki Hatada, Masahide Munemura, Kohji Fukunaga, Hideyuki Yamamoto, Masao Maeyama, Eishichi Miyamoto

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Calmodulin and Ca2+‐ and calmodulin‐dependent protein kinase were identified in the rat anterior pituitary gland. The concentration of calmodulin was 1.18 ± 0.11 μg/mg protein (n = 7) in the cytosol fraction. The calmodulin of the anterior pituitary gland co‐migrated with brain calmodulin on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The Ka value of the partially purified enzyme for Ca2+ was 3.3 μ.M in the presence of 0.30μ.M calmodulin. Trifluoperazine and chlorpromazine, calmodulin‐interacting agents, inhibited enzyme activity, with Ki values of 1.3 and 2.6 x 10‐5M, respectively. The enzyme was resolved into two peaks of activity, with sedimentation coefficients of 5.5 S and 16.5 S, by sucrose density gradient centrifugation. At least nine proteins were phosphorylated by the enzyme in a Ca2+‐ and calmodulin‐dependent manner. In light of these results, the possibility that calmodulin and the calmodulin‐activatable protein kinase system are involved in the mediation of the Ca2+ effect on hormone release from the anterior pituitary gland must be given consideration.

Original languageEnglish
Pages (from-to)1082-1089
Number of pages8
JournalJournal of Neurochemistry
Volume40
Issue number4
DOIs
Publication statusPublished - 1983 Apr
Externally publishedYes

Keywords

  • Anterior pituitary gland
  • Ca‐ and calmodulin‐dependent protein kinase
  • Stimulus‐secretion coupling.

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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