Regulation of oxytocin secretion.
A baby sucks at a mother's breast for comfort and, of course, for milk. Milk is made in specialized cells of the mammary gland, and for a baby to feed, the milk must be released into a collecting chamber from where it can be extracted by sucking. Milk "let-down" is a reflex response to the suckling and kneading of the nipple--and sometimes in response to the sight, smell, and sound of the baby--and is ultimately affected by the secretion of oxytocin. Oxytocin has many physiological roles, but its only irreplaceable role is to mediate milk let-down: oxytocin-deficient mice cannot feed their young; the pups suckle but no milk is let down, and they will die unless cross-fostered. Most other physiological roles of oxytocin, including its role in parturition, are redundant in the sense that the roles can be assumed by other mechanisms in the absence of oxytocin throughout development and adult life. Nevertheless, physiological function in these roles can be altered or impaired by acute interventions that alter oxytocin secretion or change the actions of oxytocin. Here we focus on the diverse stimuli that regulate oxytocin secretion and on the apparent diversity of the roles for oxytocin.
Leng
Gareth
G
Centre for Integrative Physiology, The University of Edinburgh College of Medicine and Veterinary Sciences, Edinburgh EH8 9XD, United Kingdom.
Caquineau
Celine
C
Sabatier
Nancy
N
D000818:Animals; D005260:Female; D006801:Humans; D007031:Hypothalamus / Q000502:physiology; D008297:Male; D008893:Milk Ejection; D009994:Osmolar Concentration; D010121:Oxytocin / Q000378:metabolism*; D036801:Parturition / Q000502:physiology; D010410:Penile Erection; D010904:Pituitary Gland, Posterior / Q000502:physiology; D012725:Sexual Behavior; D013312:Stress, Physiological; D013950:Thymus Gland; D000521:alpha-MSH / Q000502:physiology
D010121:Oxytocin; D000521:alpha-MSH