Chaudhury & Chaudhury (1962) reported that both local and systemic injection of oxytocin caused a significant increase in weight of the pigeon's crop sac and suggested that a direct prolactin-like effect of oxytocin on the crop was indicated by their results. Since the crop sac response is regarded as specific and is of great value in the assay of prolactin it was felt imperative to investigate the suggested prolactin-like action of oxytocin. The results to be reported below show no true prolactin-like effect from local oxytocin but demonstrate that the preparations used caused local irritation. The increased weight of the crop sacs observed by Chaudhury & Chaudhury can therefore readily be explained as due to inflammatory thickening. The results obtained with systemic oxytocin also failed to show clear-cut evidence of a prolactin-like crop sac response.
EXPERIMENTAL METHODS AND RESULTS
Common domestic pigeons (Columba livia) of both sexes weighing 180–293 g.