This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Prolactin: 
Select and explain. 
A. Has somatotropic activity., B. It flow can cause infertility in women., C. Can suppress menstrual cycle in lactating women., D. Levels are increased by dopamine.
C: Can suppress menstrual cycle in lactating women.
Answer: C: Can suppress menstrual cycle in lactating women. 
Explanation: Prolactin, though structurally related to growth hormone does not share its somatotropic activity. Dopamine binds to the lactotropes and inhibits the synthesis and release of prolactin. Hyperprolactinemia suppresses the hypothalamic-pituitary-gonadal axis, causes infertility in women and suppresses the normal menstrual cycle in lactating women.