Prolactin release during nursing and breast stimulation in postpartum and nonpostpartum subjects
Noel, G.L.; Suh, H.K.; Frantz, A.G.
Journal of Clinical Endocrinology and Metabolism 38(3): 413-423
1974
ISSN/ISBN: 0021-972X PMID: 4815172 DOI: 10.1210/jcem-38-3-413Document Number: 518165
The effect of suckling and breast stimulation on plasma prolactin measured by homologous radioimmunoassay was studied in nursing women, normal, non-lactating women and men, chlorpromazine-treated women, pregnant women and in women with galactorrhoea. In nursing women during the 1st 6 wk post partum plasma prolactin was increased before nursing and rose further during 30-min suckling to a peak value 8.5-fold greater than baseline level at termination of nursing. Nursing women between 7 and 28 wk post partum had normal plasma prolactin levels before nursing with increases up to 6-fold at the end of nursing. When women were allowed to play with but not nurse their infants, plasma prolactin level did not increase despite the occurrence of milk ejection, whereas stimulation with a breast pump for 30 min produced an elevation of prolactin level similar to that during suckling. Stimulation of the breast with a breast pump for 30 min produced significant prolactin increases in 7 of 18 normal women but no increase in normal men. Self-stimulation of the nipple also produced prolactin increases in a minority of normal women. Chronic chlorpromazine treatment raised basal prolactin but did not enhance sensitivity to breast stimulation in 4 subjects. Breast pump stimulation caused a prolactin rise in all of 3 pregnant women and induced lactation in one woman 7 months pregnant. Of 9 women with galactorrhoea, only 1 had increased plasma prolactin after breast pump or manual stimulation.