The pituitary hormone that stimulates the secretion of milk from the mammary glands –

Correct option is D

Sol. Prolactin, secreted by the anterior pituitary gland, is the primary hormone responsible for milk production (lactogenesis) in the mammary glands after childbirth. It stimulates the alveolar cells in the breasts to synthesize and secrete milk. Its levels rise significantly after delivery, especially when nipple stimulation continues through breastfeeding. Prolactin also suppresses ovulation in lactating women by inhibiting gonadotropins.
Explanation of each option:
· (a) Oxytocin – Involved in milk ejection (let-down reflex), not milk secretion. It is released by the posterior pituitary.
· (b) Progesterone – Important for maintaining pregnancy, but it inhibits milk secretion before delivery.
· (c) Estrogen – Promotes breast development during pregnancy but, like progesterone, inhibits lactation until after birth.
· (d) Prolactin – Correct. Directly stimulates the production and secretion of breast milk post-delivery.