About Lesson
Milk secretion
- Prolactin secreted by anterior pituitary gland causes breast changes during lactation.
- Prolactin also stimulates the production of milk
- Estrogen increases secretion of prolactin and along with prolactin promotes breast growth and differentiation.
- Estrogen along with progesterone , estrogen antagonizes prolactin action on milk production and milk secretion
- Following parturition ,estrogen and progesterone concentration in plasma falls due to absence of placenta so milk production is increases due to effect of prolactin .
- Large secretory burst of prolactin occurs during each nursing period.
- This episodic burst of prolactin signals the breasts for maintenance of milk production .
- These prolactin pulse continue for several days after the mother completely stop nursing her infant .
- The mechanism mediating prolactin pulses is initiated by stimulation of nipple receptor by suckling that send afferent input to hypothalamus .
- This input inhibits hypothalamic release of dopamine .
- Decreased dopamine release from hypothalamus stimulates prolactin secretion.
- Prolactin also inhibit GnRH secretion from hypothalamus that prevent ovulation therefore , till mother continues to nurse the baby ,normally pregnancy does not occur.
- Suckling also stimulate milk ejection reflex.