Prolactin Research Paper

866 Words4 Pages
PHYSIOLOGICAL FUNCTION OF PROLACTIN Prolactin provides the body with sexual gratification after sexual acts. The hormone counteracts the effect of dopamine, which is linked to sexual arousal. This is thought to cause the sexual refractory period. The amount of prolactin can be an indicator for the amount of sexual satisfaction and relaxation. Elevated levels of prolactin decrease the levels of sex hormones estrogen in women and testosterone in men.Prolactin within the normal reference ranges can act as a weak gonadotropin, but at the same time suppresses GnRH secretion. The exact mechanism by which it inhibits GnRH is poorly understood. Physiologic levels of prolactin in males enhance luteinizing hormone-receptors in Leydig…show more content…
Vasoactive intestinal peptide and peptide histidine isoleucine help to regulate prolactin secretion in humans.Prolactin follows diurnal and ovulatory cycles. Prolactin levels peak during REM sleep and in the early morning. Many mammals experience a seasonal cycle.During pregnancy, high circulating concentrations of estrogen and progesterone increase prolactin levels by 10- to 20-fold. Estrogen and progesterone inhibit the stimulatory effects of prolactin on milk production. The abrupt drop of estrogen and progesterone levels following delivery allow prolactin—which temporarily remains high—to induce lactation. Sucking on the nipple offsets the fall in prolactin as the internal stimulus for them is removed. The sucking activates mechanoreceptors in and around the nipple. These signals are carried by nerve fibers through the spinal cord to the hypothalamus, where changes in the electrical activity of neurons that regulate the pituitary gland increase prolactin secretion. The suckling…show more content…
In a study on female volunteers under hypnosis, prolactin surges resulted from the evocation, with rage, of humiliating experiences, but not from the fantasy of nursing. Hypersecretion is more common than hyposecretion. Hyperprolactinemia is the most frequent abnormality of the anterior pituitary tumors, termed prolactinomas. Prolactinomas may disrupt the hypothalamic-pituitary gonadal axis as prolactin tends to suppress the secretion of GnRH from the hypothalamus and in turn decreases the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary, therefore disrupting the ovulatory cycle.[28] Such hormonal changes may manifest as amenorrhea and infertility in females as well as impotence in males. Inappropriate lactation (galactorrhoea) is another important clinical sign of

More about Prolactin Research Paper

Open Document