Pup Survival and Prolactin Levels in Nicotine-Treated Lactating Rats 1

Summary Administration of 0.5 and 1 mg nicotine tartrate twice daily to female rats through pregnancy and lactation affected neither duration of pregnancy nor litter size at birth. However, pups born to females given the higher dose of nicotine were lighter in weight at birth than pups in the two other groups, and most of them died of starvation before weaning because the mother's mammary glands contained so little milk. Blood was collected via a chronic intra-atrial cannula, and radioimmunoassay of prolactin was performed. Plasma prolactin levels of the group receiving the high dose of nicotine were much lower than in the low dose nicotine and saline groups. It is suggested that failure of prolactin release following chronic nicotine administration was responsible for low milk production and starvation of the pups. The mechanism by which nicotine affects prolactin levels may involve effects on brain catecholamines. We thank Mrs. Sylvia Barr for the drawing of the figure and Mrs. Frances Smith for secretarial aid.