Stimulus for prolactin release is ?
Dopamine
Hyperglycemia
Sleep
Nipple stimulation
Ans. is'd'i.e., Nipple stimulation[Ref: Human physiology p.383)Prolactin is the only pituitary hormone which is primarily under inhibitory control of hypothalamus .Its secretion is suppressed by dopamine (Prolactin inhibitory substance) secreted by hypothalamus.