The initiation of human lactation and prolactin response to suckling
Aono, T.; Shioji, T.; Shoda, T.; Kurachi, K.
Journal of Clinical Endocrinology and Metabolism 44(6): 1101-1106
1977
ISSN/ISBN: 0021-972X PMID: 874046 DOI: 10.1210/jcem-44-6-1101Document Number: 460302
Serum levels of prolactin (PRL) in 18 nursing mothers were determined by homologous radioimmunoassay, near term, immediately after delivery, and before and after a morning nursing on the 2nd, 4th and 6th post-partum day. The mothers were divided into 3 groups (good, moderate and poor lactation) according to the amount of milk produced during the 1st 5 post-partum days. Basal levels of PRL gradually declined in all groups and were not significantly different between the 3 groups. However, significant post-nursing increases in PRL levels (P<0.05) were observed 4 days (168%) and 6 days (236%) after delivery in the good lactation group, and on the 6th post-partum day (172%) in the moderate lactation group; no post-nursing increases were found in the poor lactation group. 26 nursing mothers volunteered to have a 20 min breast pump stimulation on the 5th post-partum day, and serum PRL levels were determined before and after the stimulation. Significant increases in PRL levels following uniform breast stimulation (P<0.05) were observed in all 3 groups and these were not different between groups. Data suggest that the initiation of milk secretion in the human seems to be closely related to the increase in PRL levels induced by an adequate baby's suckling.