Bromocriptine

Bromocriptine (brand names include Parlodel), an ergoline derivative, is a dopamine agonist that is used in the treatment of pituitary tumors and Parkinson's disease.

Uses
Amenorrhea, female infertility, galactorrhea, hypogonadism, and acromegaly may all be caused by pituitary problems, such as hyperprolactinaemia, and therefore, these problems may be treated by this drug.

It has also used in some countries to prevent lactation following childbirth if the mother does not wish to breastfeed; one of dopamine's effects on the pituitary is as an antagonist of prolactin production by lactotrophs. However, the FDA removed this indication in 1995, because of concerns with respect to an increased risk of heart attack, seizure and stroke.

Because of prolactin's role in stimulating proliferation of the T-lymphocytes of the immune system, bromocriptine has also been used to suppress the immune system in organ transplant patients.

Since bromocryptine acts as a dopamine agonist, it has potential use in treating cocaine addiction, since the addictive effects of cocaine are caused by it blocking dopamine reuptake. Although it has negligible subjective effects when administered alone, studies show it has the potential to significantly ease the cocaine withdrawal syndrome.

There appear to be some connections between insulin insensitivity and dopamine. A company called Veroscience is using bromocriptine to treat diabetes and obesity, and their website postulates a connection between neurotransmitters and seasonal variation in insulin sensitivity among vetebrate animals. There are also some connections between temperature and dopamine and serotonin production. In addition, new research indicates that patients with diabetes are more likely to develop parkinson's disease, which is characterized by a dopamine deficiency in the brain.

Parkinson's disease
Bromocriptine is an agonist of D2 dopamine receptors and has therefore been used as a treatment for Parkinson's disease. Early studies suggested that treating patients with bromocriptine before levodopa would delay the onset of side effects such as dyskinesia. However, a recent Cochrane review found a lack of evidence to support this view.

Structure
Like all ergopeptides, bromocriptine is a cyclol; two peptide groups of its tripeptide moiety (shown in black at the upper left of the Figure) are crosslinked, forming the >N-C(OH)< juncture between the two rings with the amide functionality.