Chemical Coordination and Regulation Question 54
54. Which one of the following hormone stimulates the “let-down” (release) of milk from the mother’s breasts when the baby is sucking ?
[1996]
(a) Progesterone
(b) Oxytocin
(c) Prolactin
(d) Relaxin
Show Answer
Answer : b
Hints & Solutions
(b) Prolactin is a proteinaceous hormone released by anterior lobe of pituitary. Prolactin supplements the action of gonadal hormones in stimulating the growth and activity of female mammary gland during pregnancy and lactation. Oxytocin released by the posterior lobe of pituitary gland, is important for the mechanism of ejection of milk from the mammary glands due to sucking of breasts by infant. Progesterone, released by corpus luteum brings about pregnancy changes such as uterine growth, implantation of embryo etc. Relaxin is a proteinaceous hormone secreted by corpus luteum towards the end of gestation period for loosening and softening of pelvic ligaments, relaxing of uterus for easing parturition.
