SEPARATION OF OXYTOCIN FROM THE SUBSTANCES THAT INTERFERE WITH ITS BIOLOGICAL ASSAY ON THE ISOLATED RAT MAMMARY GLAND

Abstract

In an investigation on the isolation of oxytocin from the blood of lactating women (Coch, Fielitz, Brovetto, Cabot, Coda & Fraga, 1967) the hormone was assayed by measuring its effect on a strip of rat mammary gland. This preparation is suitable for detecting very small amounts of oxytocin, but it is also very sensitive to acetylcholine, adrenaline, noradrehaline, lysine vasopressin, histamine and to a lesser extent to 5-hydroxytryptamine (Smith, 1961; Rydén & Sjoholm, 1962). The separation of oxytocin from these interfering substances by paper chromatography or paper electrophoresis is now reported. Since hypertensin and bradykinin could also have been present in the blood extract used, we studied the effect of these drugs on a strip of rat mammary gland and found that neither of these peptides produced a measurable effect, even at concentrations as high as 1 μg./ml. For the separations Whatman 3 mm. filter paper was used, purified by