Deamino-oxytocin: Inactivation by Plasma of Women in Labor

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Science  05 Apr 1968:
Vol. 160, Issue 3823, pp. 81-82
DOI: 10.1126/science.160.3823.81


Incubation of deamino-oxytocin with plasma obtained from women in labor reduced the potency of this analog of oxytocin when assayed on an isolated strip of mammary gland taken from a lactating rat. Plasmas of nonpregnant women had no detectable effect on this activity of deamino-oxytocin, and the effect of plasmas from women just previous to the beginning of labor was not significant. The original. activities of the incubated deamino-oxytocin solutions could be restored by treatment with hydrogen peroxide. The inactivation may be caused by reductive cleavage of the disulfide bridge of deamino-oxytocin, this bridge being reformed by oxidation.