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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat and bovine adrenal cortical microsomal fractions isolated at 27,000 x g and 105,000 x g accumulated Ca2+ by a nonmitochondrial, ATP-dependent uptake system that was stimulated by ammonium oxalate. ACTH (2 mU/ml) significantly increased Ca2+ uptake in bovine adrenal cortical microsomes and in adrenal microsomes from acutely hypophysectomized rats, but only when the hormone was preincubated with intact tissue and not when it was added after homogenization. ACTH did not stimulate C2+ uptake in adrenal microsomes isolated from nonhypophysectomized, ether-stressed rats, in which basal Ca2+ uptake was higher than that observed in microsomes from hypophysectomized animals. The peptides oxytocin, insulin, and TSH did not stimulate Ca2+ uptake by adrenal cortical microsomes. ACTH preincubated with intact tissue had no effect on Ca2+ uptake in microsomes from liver, kidney, esophagus, or aorta. cAMP, 5'-AMP, and several other nucleotides, nucleosides, and related compounds stimulated adrenal cortical microsomal Ca2+ uptake by as much as 540% of control. The stimulatory effects of nucleotides, unlike those of ACTH, were apparent even when the agents were added after homogenization. However, like ACTH, the nucleotides were unable to stimulate Ca2+ uptake when they were added to isolated membrane vesicles during Ca2+ uptake measurements. It is suggested that the microsomal Ca2+ uptake system may respond to physiological stimulants and regulate Ca2+ availability in the intact cell.
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PMID:The effect of adrenocorticotropin and nucleotides on Ca2+ uptake in adrenal cortical microsomal vesicles. 21 5

Uterotonic peptide hormone oxytocin has been studied for its effect on ATP-dependent accumulation of Ca2+ nonsensitive to the effect of ruthenium red (10 microM) that is potentiated by Ca2+-precipitating anion - oxalate. That was studied in experiments made on the suspension of myometrium cells from estrogenized rats processed by digitonin (0.1 mg/ml) with the aim permeabilization of plasmatic membrane. The preliminary processing of intact myocytes by oxytocin solution (final concentration 100 mM) to permeabilization of plasmatic membrane causes partial inhibition (stimulated by oxalate by 25-30% (0-10 mM) of Mg2+, ATP-dependent accumulation of Ca2+ in nonmitochondrion intracellular calcium depot of perforates smooth-muscled cells. The value of the component of power-dependent accumulation of Ca2+, that is inhibited by oxytocin, increased with both the incubation time and oxalate concentration. Thapsigargin and cyclopiasonium acid, selective inhibitors of calcium pump of endo(sarco)plasmatic reticulum, when used in saturation concentration (50 mM and 10 mM, respectively), completely inhibit the component of Mg2+, ATP-dependent accumulation of Ca2+ in nonmitochondrial intracellular calcium depot that is stimulated with oxalate (< 10 mM) and inhibited with oxytocin (100 mM). It is concluded that oxytocin partially inhibits Mg2+, ATP-dependent calcium pump of myometrium cell endoplasmic reticulum.
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PMID:[Treatment of intact myometrial cells with oxytocin inhibits Mg2+, ATP-dependent accumulation of Ca2+ in endoplasmic reticulum]. 922 49

The effect of the nonionic detergent digitonin on ruthenium red-insensitive, oxalate-stimulated, and thapsigargin-suppressed accumulation of Ca2+ by suspension of myometrial cells from ATP- and Mg(2+)-containing incubation medium was studied using passive loading with 45Ca2+. The dependence of Ca2+ accumulation by the cells on the concentration of digitonin is bell-shaped, the maximal Ca2+ uptake being observed at 0.05-0.1 mg/ml digitonin. Myocytes chemically skinned with digitonin represent a suitable experimental model for studying kinetic properties of the uterine myocyte endoplasmic reticulum Mg2+, ATP-dependent Ca2+ pump and assessing sensitivity of this Ca(2+)-transporting system to various effectors including the uterotonic octapeptide oxytocin.
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PMID:Suspension of smooth muscle cells treated with digitonin as a model for studying the myometrial endoplasmic reticulum calcium pump. 948 75