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Prolactin has a wide variety of effects. It stimulates the mammary glands to produce milk (): increased serum concentrations of prolactin during pregnancy cause enlargement of the mammary glands and prepare for milk production, which normally starts when levels of progesterone fall by the end of pregnancy and a suckling stimulus is present.
A prolactin cell (also known as a lactotropic cell, epsilon acidophil, lactotrope, lactotroph, mammatroph, mammotroph) is a cell in the anterior pituitary which produces prolactin (a peptide hormone) in response to hormonal signals including dopamine (which is inhibitory), thyrotropin-releasing hormone and estrogen (especially during pregnancy), which are stimulatory.
During pregnancy, the production of prolactin by the mother increases steadily, starting at 6–8 weeks of gestation and continuing until the end of the pregnancy. [32] Prolactin levels in the human fetal circulation see a gradual increase from around 30 weeks of gestation until birth. [ 32 ]
The early embryo has 1–2 weeks in order to produce sufficient hCG in order to stabilize the endometrial lining to allow for blastocyst attachment. The dramatic increase in trophoblastic and corpus luteal hCG synthesis signals both blastocyst [ 5 ] and corpus luteal [ 6 ] production of P4, crucial for the maintenance of the endometrium .
Hyperprolactinemia, characterized by abnormally high levels of prolactin, may cause galactorrhea (production and spontaneous flow of breast milk), infertility, and menstrual disruptions in women. In men, it can lead to hypogonadism, infertility and erectile dysfunction. Prolactin is crucial for milk production during pregnancy and lactation.
From about the 16th week of pregnancy the breasts are able to begin to produce milk. It’s not unusual for small amounts of straw-coloured fluid called colostrum to leak from the nipples. Breast lumps also sometimes develop during pregnancy but these are generally benign cysts or fibroadenoma which are not cause for concern. If the nipples ...
High levels of prolactin during pregnancy and breastfeeding also increase insulin resistance, increase growth factor levels (IGF-1) and modify lipid metabolism in preparation for breastfeeding. During lactation, prolactin is the main factor maintaining tight junctions of the ductal epithelium and regulating milk production through osmotic balance.
[1] [2] It is involved in lobuloalveolar maturation of the mammary glands during pregnancy and the induction and maintenance of lactation following parturition. [3] Hormones that control the secretion of prolactin from the pituitary gland include dopamine ("prolactin-inhibiting factor", or "PIF"), estradiol , progesterone , thyrotropin ...