Formation of prolactin: The hormone prolactin of the pituitary gland is also called lactotropin and is a peptide hormone.
Regulation
Regulation of prolactin: The PRH (prolactin releasing hormone) and the TRH (thyrooliberin) of the hypothalamus stimulate the release of prolactin from the anterior pituitary gland, which has a day-night rhythm. Oxytocin and several other substances also have a stimulating effect. In contrast, dopamine (prolactostatin) inhibits the release of the hormone.
As negative feedback, prolactin increases the release of dopamine and thus inhibits its release itself. Dopamine secretion is inhibited by the hormones estradiol and progesterone. Consequently, prolactin secretion increases when oestradiol or progesterone levels are high (low dopamine levels).
The corresponding receptor is one of the cell surface receptors. Prolactin causes breast growth during pregnancy and lactogenesis. In addition, by inhibiting FSH and GnRH, this hormone prevents the maturation of follicles in the ovary and thus prevents ovulation.
The increased release of the hormone during breastfeeding by sucking on the breast therefore acts as a kind of contraceptive protection. Prolactin is also produced in men, although the function of the hormone is unclear in them.
