ROLE OF CALCIUM IN THE RELEASE OF VASOPRESSIN AND OXYTOCIN FROM POSTERIOR PITUITARY PROTEIN

ABSTRACT Using film dialysis experiments of crude posterior pituitary protein in 0.1 m acetic acid/sodium acetate buffer (pH 5.6) it was demonstrated that addition of calcium in concentrations of 0.2 or 0.5 mm increased the rate of dialysis of vasopressin activity from the film of protein solution....

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Bibliographic Details
Published inActa endocrinologica (Copenhagen) Vol. 50; no. 3; pp. 357 - 364
Main Author Thorn, N A
Format Journal Article
LanguageEnglish
Published Denmark 01.11.1965
Subjects
Calcium
Dialysis
In Vitro Techniques
Neurosecretion
Oxytocin
Pituitary Gland, Posterior
Proteins
Vasopressins
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Summary:ABSTRACT Using film dialysis experiments of crude posterior pituitary protein in 0.1 m acetic acid/sodium acetate buffer (pH 5.6) it was demonstrated that addition of calcium in concentrations of 0.2 or 0.5 mm increased the rate of dialysis of vasopressin activity from the film of protein solution. Sodium chloride, magnesium chloride or acetylcholine had no such effect. Calcium in a concentration of 0.2 mm also increased the rate of dialysis of oxytocin activity from the protein solution. The results seem to support the hypothesis that calcium ions function in the excitation-secretion coupling for vasopressin and oxytocin by releasing hormone peptide from its binding to neurophysin within the neurosecretory nerve endings. Thus the hormone becomes free to diffuse into the blood stream.
ISSN:0804-4643
0001-5598
1479-683X
DOI:10.1530/acta.0.0500357