Bile, prolactin, and the maternal pheromone

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Science  01 Apr 1977:
Vol. 196, Issue 4285, pp. 81-83
DOI: 10.1126/science.190682


When bile from females that had been lactating for 21 days was injected into the cecum of male rats it induced release of a maternal pheromone. Males injected with bile drawn from females in which prolactin had been inhibited, or from females that had been lactating for only 5 days, did not emit the pheromone. These data suggest a sex difference in the way prolactin alters the composition of bile so that the female can emit the maternal pheromone while the male normally cannot.