Oxytocin effect on myoepithelium of the breast throughout pregnancy

¹ Departments of Obstetrics and Gynecology and of Physiology and Pharmacology, New York Medical College, Flower and Fifth Avenue Hospitals, New York City

Sensitivity of the myoepithelium of the human breast to oxytocin during gestation has been evaluated in terms of threshold, threshold intensity, threshold lag period, dose response, slope of dose response, and multiple responses. A correlation of these data with advance in gestation was sought. Thresholds, threshold intensities, and threshold lag periods did not vary with age of gestation. Threshold lag periods were inversely proportional to the amplitude of the ensuing response, while amplitude of response was directly proportional to the log of the dose of oxytocin. Slopes of dose response did not vary with gestational age. Spontaneous myoepithelial contractions were found to occur in patients during gestation. Increasing sensitivity (magnitude of response at a given dose) to oxytocin, as found in the uterus, was not evident in the breast during gestation.

Submitted on May 23, 1963