This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and Reproduction, Subject name: Physiology
[{'content': 'Prolactin inhibiting substance is: \nSelect and explain. \nA. Dopamine, B. Adrenaline, C. Thyroxin, D. ACTH', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (Dopamine) Ref: Ganong,22nd ed, p. 423Dopamine is the hypothalamic prolactin inhibiting hormone.Prolactin facilitates dopamine secretion in median eminence, thus acting in a negative feed back fashion to inhibit its own secretion.Factors that increase prolactinFactors that decrease prolactin1. Sleep, nursing stress, exercise2. Pregnancy, breast stimulation3. Section of pituitary stalk.4. TRH, estrogen5. Phenothiazines, butyrophenons.1. L-Dopa by increasing dopamine2. Apomorphine3. Bromocriptine4. Ergot derivatives.KememberHypoglycaemia increases prolactin whereas glucose produces no change.Opioids increase prolactin whereas apomorphine decreases prolactin.', 'role': 'assistant'}]