Prolactin (PRL) is a polypeptide hormone, with a molecular weight of approximately 23.000 Da. It is composed of a single chain of 198 amino acids and it is secreted from the anterior lobe of the pituitary gland.
Prolactin (PRL) is a polypeptide hormone, with a molecular weight of approximately 23.000 Da. It is composed of a single chain of 198 amino acids and it is secreted from the anterior lobe of the pituitary gland. The synthesis and secretion of prolactin are regulated by hypothalamic factors such as the thyrotropin-releasing hormone (TRH) that stimulates its production and the dopamine that inhibits it.
Prolactin plays its most important role in females, stimulating the development of the mammary gland and starting and maintaining the milk secretion.
The basal concentrations of prolactin in adults present significant circadian oscillations, with higher values during the sleeping hours and lower values during the waking hours.
Physical exercise and stress can also cause an increase of serous prolactin, as well as some medicines such as sulpiride and chlorpromazine. As regards to its physiological function, prolactin rises during pregnancy and reaches its maximum level around the 38° week. After delivery, prolactin still maintains high values for the whole nursing period.
The assay of prolactin is significantly useful to clarify many clinical pictures concerning sterility problems, both in males and females, or relative to hypothalamic-pituitary axis dysfunctions.