Subject of this literature review, is the mechanism of prolactin inhibition and the clinical actions of the first dopamine agonist introduced in endocrine practice, bromocriptine. 2Br-a-methyl-ergocriptine (CB154-bromocriptine mesylate) (Parlodel, Provide!) was produced in 1967 and has initially been used in the treatment of hyperprolactinaemia. Bromocriptine was found to inhibit prolactin secretion in all mammals and fishes that have so far been examined, either under physiological conditions or during the phase that the hormone secretion is stimulated with physiological, pharmacological or surgical criteria. The drug acts directly on the pituitary lactotrophs and reduces prolactin secretion without influencing the hormonal synthesis but with reducing the out cellular events. It suppresses post partum lactation and galactorroea of any cause. It restores infertility due to hyperproiactinaemia and it has been so far particularly useful in the treatment of micro and macroprolactinomas. It has also been used as a secondary form of treatment in acromegaly. It has also been useful in the treatment of Parkinson's disease. Prolactinomas may show resistance to bromocriptine and other dopamine agonists in both prolactin levels and tumour size reduction and this may be due to the fact that some tumours have reduced number of D2 receptors. Another disadvantage of the dopamine agonist therapy is its supposed lifelong requirement, since after discontinuation, prolactin levels increase and tumour size may show clear-cut re-expansion. Newer and stronger dopamine agonists with longer duration of action have been developed through the years to overcome the side effects of bromocriptine and its three daily dosage requirement; till now most of these drugs are being compared with the well known clinical behaviour of bromocriptine.
|Number of pages||7|
|Journal||Epitheorese Klinikes Farmakologias kai Farmakokinetikes|
|Publication status||Published - 1 Dec 2009|
- dopamine agonist resistance
- prolactin suppression
- tumour reduction