Prolactin (PRL) is a polypeptide hormone that is synthesized and released from lactotroph cells in the pituitary. Episodic release of the hormone from the anterior pituitary is under the control of PRL-releasing and inhibitory factors secreted from the hypothalamus. Hypothalamic dopamine inhibits PRL release. The hormone PRL, which is mainly responsible for lactation, may also act as a neurotransmitter, growth factor or immunoregulator.
The normal range of prolactin values is 5-20 ng/mL. Although the PRL level in women is slightly higher than in men, it is below 25 ng/mL. A single PRL measurement is sufficient to make a diagnosis unless there is excessive stress during blood collection. However, in order to eliminate the stress factor that will occur during blood collection, some patients will be given a more accurate result by attaching a cannula and making 2-3 measurements with 15-20 minutes intervals and calculating the average PRL value. Sleep, exercise, emotional and physical stress, breast or chest wall stimulation, coitus, and a high protein diet can increase PRL levels. PRL measurement can be made preferably 4 hours after ingestion of protein food.
Prof. Dr. Ayşe ÇARLIOĞLU Internal Medicine - Internal Medicine, Endocrinology and Metabolism Diseases