Hyperprolactinaemia (BrE) or hyperprolactinemia (AmE) is the presence of abnormally-high levels of prolactin in the blood. Normal levels are less than 580 mIU/L for women, and less than 450 mIU/L for men.
Prolactin is a peptide hormone produced by the anterior pituitary gland primarily associated with lactation and plays important breast development during pregnancy. Hyperprolactinaemia may cause production and spontaneous flow of breast milk and disruptions in the normal menstrual period in women and hypogonadism, infertility and erectile dysfunction in men.
Hyperprolactinaemia can be a part of normal body changes during pregnancy and breastfeeding. It can also be caused by diseases affecting the hypothalamus and pituitary gland. It can also be caused disruption of the normal regulation of prolactin levels by drugs, medicinal herbs and heavy metals. Hyperprolactinaemia may also be the result of disease of other organs such as the kidneys, ovaries and thyroid.
Hyperprolactinaemia may be caused by either disinhibition (e.g., compression of the pituitary stalk or reduced dopamine levels) or excess production from a prolactinoma (a pituitary gland adenoma tumour). A blood serum prolactin level of 1000â€"5000 mIU/L could be from either mechanism, but >5000 mIU/L is likely due to the activity of an adenoma with macroadenomas (large tumours over 10 mm diameter) whose levels of prolactin are up to 100,000 mIU/L.
Hyperprolactinemia inhibits gonadotropin-releasing hormone (GnRH) by increasing the release of dopamine from the arcuate nucleus of the hypothalamus (dopamine inhibits GnRH secretion), thus inhibiting gonadal steroidogenesis, which is the cause of many of the symptoms described below.
There is a suspicion that -->“Minoxidil”<-- a potassium channel agonist, may be related to the development of this disease. A two-year test with Minoxidil, under normal dosing parameters, was carried out on rats, which caused pheochromocytomas in both males and females, and preputial gland adenomas in males.
Physiological causes (i.e., as result of normal body functioning): pregnancy, breastfeeding, stress, sleep.
Use of “Prescription Drugs” is the most common cause of hyperprolactinaemia. Prolactin secretion in the pituitary is normally suppressed by the brain chemical dopamine. Drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete prolactin.
These drugs include the major tranquilizers (phenothiazines), trifluoperazine (Stelazine), and haloperidol (Haldol); some antipsychotic medications; metoclopramide (Reglan), used to treat gastroesophageal reflux and the nausea caused by certain cancer drugs; and, less often, alpha-methyldopa and reserpine, used to control hypertension; and oestrogens and TRH.
Prolactinoma or other tumors arising in or near the pituitary, such as those that cause acromegaly or Cushing’s syndrome, may block the flow of dopamine from the brain to the prolactin-secreting cells, likewise, division of the pituitary stalk or hypothalamic disease. Other causes include chronic renal failure, hypothyroidism, and sarcoidosis.
Some women with polycystic ovary syndrome may have mildly-elevated prolactin levels. Apart from diagnosing hyperprolactinaemia and hypopituitarism, prolactin levels are often determined by physicians in patients that have suffered a seizure, when there is doubt as to whether this was an epileptic seizure or a non-epileptic seizure. Shortly after epileptic seizures, prolactin levels often rise, whereas they are normal in non-epileptic seizures.
In many patients, elevated levels remain unexplained and may represent a form of hypothalamic-pituitary dysregulation.
In men, the most common symptoms of hyperprolactinemia are decreased libido, erectile dysfunction, and infertility. Because men have no reliable indicator such as menstruation to signal a problem, many men with hyperprolactinemia being caused by an adenoma may delay going to the doctor until they have headaches or eye problems caused by the enlarged pituitary pressing against nearby optic nerves.
They may not recognize a gradual loss of sexual function or libido. Only after treatment do some men realize they had a problem with sexual function. In men excess prolactin may also cause Gynecomastia. Hyperprolactinaemia can lead to osteoporosis.
A doctor will test for prolactin blood levels in women with unexplained milk secretion (galactorrhea) or irregular menses or infertility, and in men with impaired sexual function and, in rare cases, milk secretion. If prolactin is high, a doctor will test thyroid function and ask first about other conditions and medications known to raise prolactin secretion.
While a plain X-ray of the bones surrounding the pituitary may reveal the presence of a large macro-adenoma, the small micro-adenoma will not be apparent.
Magnetic resonance imaging (MRI) is the most sensitive test for detecting pituitary tumors and determining their size. MRI scans may be repeated periodically to assess tumor progression and the effects of therapy. Computed Tomography (CT scan) also gives an image of the pituitary, but it is less sensitive than the MRI. In addition to assessing the size of the pituitary tumor, doctors also look for damage to surrounding tissues, and perform tests to assess whether production of other pituitary hormones is normal. Depending on the size of the tumor, the doctor may request an eye exam with measurement of visual fields.
The hormone prolactin is downregulated by dopamine and is upregulated by estrogen. A falsely-high measurement may occur due to the presence of the biologically-inactive macroprolactin in the serum. This can show up as high prolactin in some types of tests, but is asymptomatic.
Those with abnormally-high levels of prolactin in their blood should consider Dopamine agonists.
Dopamine agonists have been around for many decades, and their pro-libido effect is well established. Apart from Dostinex, the assortment of dopamine agonists includes cabergoline, bromocriptine, pergolide, pramipexole, lisuride, apomorphine, and a few more.
Apomorphine (brand name: Uprima) is sold in “Europe” as a medication for erectile dysfunction. But it’s wrong marketing. Dopamine agonists don’t work for erections as reliably as phosphodiesterase inhibitors. They work on “libido”. Therefore, Uprima typically is a disappointment for men whose problems are primarily vascular. Uprima is sold as a medication for erectile dysfunction mainly because erectile dysfunction meanwhile is an accepted medical condition, while low libido is not.
Dopamine agonists are the agent of choice for enhancing sexual excitement, orgasm, and ejaculation. Because dopamine agonists suppress the hormone prolactin, which in turn suppresses testosterone, dopamine agonists can, in people with elevated prolactin levels, function in the same way as a testosterone replacement therapy would.
This most clearly happens in patients with pituitary cancer, which typically expresses itself in strongly elevated prolactin levels. Those afflicted by the disease have very low testosterone levels. Thus, for them, Dostinex and other dopaminergic agents work as hormonal therapy. The hormonal effects of Dostinex are less extreme in healthy subjects.
Dopamine agonists not only support sexual excitement; they also tend to enhance orgasm and make for a stronger ejaculation, though the ejaculation-enhancing effect is greater with tongkat ali, which can account for an additional half meter in ejaculatory range (and ejaculations on tongkat ali can feel like pellets, not fluid, moving through the urethra). Orgasms in general will be much more overwhelming.
It should be noted, Dopamine agonists have a downside. All the older ones can cause nausea.