Oxytocin regulates the plasma membrane Ca2+ transport in rat myometrium

A. Enyedi, J. Brandt, J. Minami, J. T. Penniston

Research output: Contribution to journalArticle

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Abstract

Development of myometrium in young female rats was stimulated by administration of diethylstilboestrol. Plasma membrane and sarcoplasmic reticulum from rat myometrium were separated by a new and rapid method using a Percoll gradient. Calcium uptake was inhibited in plasma membrane vesicles isolated from oxytocin-treated myometrium, while no consistent effect of oxytocin was found on the Ca2+ uptake in the sarcoplasmic reticulum. Oxytocin regulated the plasma membrane Ca2+ pump by decreasing its apparent affinity for Ca2+ without affecting its maximal velocity. The K( 1/2 ) for Ca2+ in the absence of calmodulin was 0.41 ± 0.04 μM in normal membranes; this was increased to 0.93 ± 0.12 μM in oxytoxin-treated membranes. Calmodulin decreased the K( 1/2 ) for Ca2+ to 0.27 ± 0.027 μM and oxytocin also increased this, to 0.46 ± 0.061 μM. The effect oxytoxin on the plasma membrane Ca2+ pump was highly dependent on the hormonal status of the animals. When the diethylstilboestrol was administered together with progesterone, the inhibitory action of oxytocin was totally suppressed, consistent with the expected action of this agent. The results suggest that regulation of the plasma membrane Ca2+ pump may be important in the prolonged elevation of intracellular Ca2+ caused by oxytocin.

Original languageEnglish
Pages (from-to)23-28
Number of pages6
JournalBiochemical Journal
Volume261
Issue number1
Publication statusPublished - 1989

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Myometrium
Oxytocin
Cell membranes
Rats
Cell Membrane
Diethylstilbestrol
Sarcoplasmic Reticulum
Pumps
Calmodulin
Membranes
Progesterone
Animals
Calcium

ASJC Scopus subject areas

  • Biochemistry

Cite this

Enyedi, A., Brandt, J., Minami, J., & Penniston, J. T. (1989). Oxytocin regulates the plasma membrane Ca2+ transport in rat myometrium. Biochemical Journal, 261(1), 23-28.

Oxytocin regulates the plasma membrane Ca2+ transport in rat myometrium. / Enyedi, A.; Brandt, J.; Minami, J.; Penniston, J. T.

In: Biochemical Journal, Vol. 261, No. 1, 1989, p. 23-28.

Research output: Contribution to journalArticle

Enyedi, A, Brandt, J, Minami, J & Penniston, JT 1989, 'Oxytocin regulates the plasma membrane Ca2+ transport in rat myometrium', Biochemical Journal, vol. 261, no. 1, pp. 23-28.
Enyedi, A. ; Brandt, J. ; Minami, J. ; Penniston, J. T. / Oxytocin regulates the plasma membrane Ca2+ transport in rat myometrium. In: Biochemical Journal. 1989 ; Vol. 261, No. 1. pp. 23-28.
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