The correct option is Prolactin.
Explanation
Lactation is regulated by specific hormones that control the development of mammary glands, the synthesis of milk, and the release of milk. The two primary hormones involved are Prolactin and Oxytocin, which have distinct functions.Detailed Analysis:
- Prolactin (Option a): This hormone is secreted by the anterior pituitary gland. Its primary function is to stimulate the synthesis and production of milk within the alveoli of the mammary glands. It promotes the growth of mammary tissue and the initiation of milk secretion after childbirth.
- Oxytocin (Option b): This hormone is released by the posterior pituitary gland. It is responsible for the milk ejection reflex (also known as the let-down reflex). It causes the contraction of myoepithelial cells surrounding the alveoli to push milk into the ducts, but it does not synthesize milk.
- Estrogen (Option c): Estrogen stimulates the growth of the ductal system in the mammary glands during pregnancy. However, high levels of estrogen during pregnancy actually inhibit the milk-secreting action of prolactin.
- LH (Option d): Luteinizing Hormone (LH) is involved in the reproductive cycle, specifically triggering ovulation and the maintenance of the corpus luteum. It does not play a direct role in lactation.
Key Takeaway:
Prolactin is responsible for milk production (synthesis), whereas Oxytocin is responsible for milk ejection (release).