Hyperprolactinaemia Health Dictionary

Prolactin is the pituitary hormone (see PITUITARY GLAND) which initiates lactation. The development of the breasts during pregnancy is ascribed to the action of OESTROGENS; prolactin starts them secreting. If lactation does not occur or fails, it may be started by injection of prolactin.

The secretion of prolactin is normally kept under tonic inhibition by the secretion of DOPAMINE which inhibits prolactin. This is formed in the HYPOTHALAMUS and secreted into the portal capillaries of the pituitary stalk to reach the anterior pituitary cells. Drugs that deplete the brain stores of dopamine or antagonise dopamine at receptor level will cause HYPERPROLACTINAEMIA and hence the secretion of milk from the breast and AMENORRHOEA. METHYLDOPA and RESERPINE deplete brain stores of dopamine and the PHENOTHIAZINES act as dopamine antagonists at receptor level. Other causes of excess secretion of prolactin are pituitary tumours, which may be minute and are then called microadenomas, or may actually enlarge the pituitary fossa and are then called macroadenomas. The most common cause of hyperprolactinaemia is a pituitary tumour. The patient may present with infertility – because patients with hyperprolactinaemia do not ovulate – or with amenorrhea and even GALACTORRHOEA.

BROMOCRIPTINE is a dopamine agonist. Treatment with bromocriptine will therefore control hyperprolactinaemia, restoring normal menstruation and ovulation and suppressing galactorrhoea. If the cause of hyperprolactinaemia is an adenomatous growth in the pituitary gland, surgical treatment should be considered.... prolactin

This drug antagonises the actions of DOPAMINE. Given orally, intramuscularly, or intravenously, it is used to treat nausea and vomiting, particularly in gastrointestinal disorders, or when associated with cytotoxics or radiotherapy. It is useful in the early treatment of MIGRAINE.

Caution is indicated in prescribing metoclopramide for elderly and young patients, and whenever hepatic or renal impairment is present, and it should be avoided in pregnancy or cases of PORPHYRIAS. Adverse effects include extrapyramidal effects (see under EXTRAPYRAMIDAL SYSTEM) and HYPERPROLACTINAEMIA with occasional TARDIVE DYSKINESIA on prolonged administration. There have also been occasional reports of drowsiness, restlessness, diarrhoea, depression and neuroleptic malignant syndrome, with rare cardiac conduction abnormalities following intravenous administration.... metoclopramide

Drugs used to quieten disturbed patients, whether this is the result of brain damage, MANIA, DELIRIUM, agitated DEPRESSION or an acute behavioural disturbance. They relieve the ?orid PSYCHOTIC symptoms such as hallucinations and thought-disorder in SCHIZOPHRENIA and prevent relapse of this disorder when it is in remission.

Most of these drugs act by blocking DOPAMINE receptors. As a result they can give rise to the extrapyramidal effects of PARKINSONISM and may also cause HYPERPROLACTINAEMIA.

Troublesome side-effects may require control by ANTICHOLINERGIC drugs. The main antipsychotic drugs are: (i) chlorpromazine, methotrimeprazine and promazine, characterised by pronounced sedative effects and a moderate anticholinergic and extrapyramidal e?ect; (ii) pericyazine, pipothiazine and thioridazine, which have moderate sedative effects and marked anticholinergic effects, but less extrapyramidal effects than the other groups; (iii) ?uphenazine, perphenazine, prochlorperazine, sulpiride and tri?uoperazine, which have fewer sedative effects and fewer anticholinergic effects, but more pronounced extrapyramidal effects.... neuroleptics

ACROMEGALY or gigantism is the result of the overactivity of, or tumour formation of cells in, the adenohypophysis which produces GROWTH HORMONE (see also PITUITARY GLAND). If this overactivity occurs after growth has ceased, acromegaly arises, in which there is gross overgrowth of the ears, nose, jaws, and hands and feet. DWARFISM may be due to lack of growth hormone.

DIABETES INSIPIDUS, a condition characterised by the passing of a large volume of URINE every day, is due to lack of the antidiuretic hormone (see VASOPRESSIN). Enhanced production of the ADRENOCORTICOTROPHIC HORMONE (ACTH) leads to CUSHING’S SYNDROME. Excessive production of PROLACTIN by micro or macro adenomas (benign tumours) leads to hyperprolactinaemia and consequent AMENORRHOEA and GALACTORRHOEA. Some adenomas do not produce any hormone but cause effects by damaging the pituitary cells and inhibiting their hormone production.

The most sensitive cells to extrinsic pressure are the gonadotrophin-producing cells and the growth-hormone producing cells, so that if the tumour occurs in childhood, growth hormone will be suppressed and growth will slow. Gonadotrophin hormone suppression will prevent the development of puberty and, if the tumour occurs after puberty, will result in amenorrhoea in the female and lack of LIBIDO in both sexes. The thyroid-stimulating hormone cells are the next to suffer and the pressure effects on these cells will result in hypothyroidism (see under THYROID GLAND, DISEASES OF).

Fortunately the ACTH-producing cells are the most resistant to extrinsic pressure and this is teleologically sound as ACTH is the one pituitary hormone that is essential to life. However, these cells can suffer damage from intracellular tumours, and adrenocortical insu?ciency is not uncommon.

Information about these disorders may be obtained from the Pituitary Foundation.... pituitary-linked disorders

n. a physiologically inactive form of the hormone prolactin, bound to immunoglobulin G to create a much bigger molecule. It is found in a small proportion of people but is important because some laboratory assays will detect it as prolactin, leading to a falsely elevated prolactin level in the blood and a misdiagnosis of hyperprolactinaemia (see prolactin).... macroprolactin

Inadequate sexual response may be due to a lack of sexual desire (LIBIDO) or to an inadequate performance; or it may be that there is a lack of satisfaction or ORGASM. Lack of sexual desire may be due to any generalised illness or endocrine disorder, or to the taking of drugs that antagonise endocrine function (see ENDOCRINE GLANDS). Disorders of performance in men can occur during arousal, penetration and EJACULATION. In the female, DYSPAREUNIA and VAGINISMUS are the main disorders of performance. DIABETES MELLITUS can cause a neuropathy which results in loss of erection. IMPOTENCE can follow nerve damage from operations on the PROSTATE GLAND and lower bowel, and can be the result of neurological diseases affecting the autonomic system (see NERVOUS SYSTEM). Disorders of satisfaction include, in men, impotence, emission without forceful ejaculation and pleasureless ejaculation. In women such disorders range from the absence of the congestive genital response to absence of orgasm. Erectile dysfunction in men can sometimes be treated with SILDENAFIL CITRATE (Viagra®), a drug that recent research suggests may also be helpful to women with reduced libido and/or inability to achieve orgasm.

Sexual dysfunction may be due to physical or psychiatric disease, or it may be the result of the administration of drugs. The main group of drugs likely to cause sexual problems are the ANTICONVULSANTS, the ANTIHYPERTENSIVE DRUGS, and drugs such as metoclopramide that induce HYPERPROLACTINAEMIA. The benzodiazepine TRANQUILLISERS can reduce libido and cause failure of erection. Tricyclic ANTIDEPRESSANT DRUGS may cause failure of erection and clomipramine may delay or abolish ejaculation by blockade of alpha-adrenergic receptors. The MONOAMINE OXIDASE INHIBITORS (MAOIS) often inhibit ejaculation. The PHENOTHIAZINES reduce sexual desire and arousal and may cause di?culty in maintaining an erection. The antihypertensive drug, methyldopa, causes impotence in over 20 per cent of patients on large doses. The beta-adrenoceptorblockers and the DIURETICS can also cause impotence. The main psychiatric causes of sexual dysfunction include stress, depression and guilt.... sexual dysfunction