The effects of prolactin on pulmonary maturation in the fetal rabbit

The effect of ovine prolactin administration on the fetal rabbit pulmonary pressure volume relationship was determined. Using pentobarbital anesthesia, on Day 24 of gestation, a midline incision on the maternal abdomen was made to expose the bicornuate uterus. Fetal rabbits in one horn of the uterus were injected intramuscularly with a dose of 1.0 mg (0.05 ml) of prolactin solution. Similarly, fetuses in the opposite horn were administered an equivalent volume of control vehicle. On Day 26 of gestation, no significant enhancement of lung maturation, as judged from the pressure volume relationship, was found to result from prolactin administration. These results suggest that prolactin does not initiate the secretion of surface active material into the alveolar lumen of the fetal lung in sufficient amounts to induce physiologic maturation of the rabbit fetal lung.