Prolactin inhibiting substance is:

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.