Keeping what 3J mentioned in mind (he does bring up a VERY good point that I somehow missed), I can give you a quick and dirty version.
Dopamine agonists are a class of chemicals that trigger your brain to release dopamine. As it has been demonstrated that prolactin has an inverse relationship with dopamine (a feel good hormone/reward stimulus), this sudden increase of dopamine will cause your pituitary gland to cease or drastically lower its production of the hormone. There are several anti-depressants in fact that utilize this very same pathway to help folks suffering from depression feel better, which is why some even note a feeling of well-being while on some DA's.
Common dopamine agonists would be cabergoline and pramipexole. Caber (for short) is often sought as it does tend to have less of an ability to make folks nauseous, but it is also much harder to procure as it is not stable in liquid form - which many research chem companies are only able to offer for legal reasons. Many folks often take .25 to .5mg of caber E3.5D (2x a week) and see positive results. As prolactin can rebound, it should be continued even
after cessation of a progestin (19-nor), or deca in this case for another week or two.
Pramipexole, or prami for short is far more commonly found as it is stable in liquid form, but it does have the propensity to make you feel ill or nauseous. My personal experience as well as a few others has been to take it right before bed (DA's can make you sleepy after ingestion) with a light protein snack such as greek yogurt or casein. 2rude4u (a member here) has even found that prami may elevate natural growth hormone levels by up to 300%, which sounds like a bonus to me. Prami is often dosed at .25mg EOD for a week and then increased once a slight tolerance has built up to either .25mg ED or .5mg EOD. If problems with prolactin are still evident at this dose, it may be increased to .5mg ED or 1mg EOD. I have yet to see many studies indicating any negatives associated with dropping prolactin levels too low in men, but I feel caution should still be observed when increasing a dose.
Other notable side effects of DA's include: A shortened refractory period (being able to have sex again shortly after climax), a feeling of well-being, slight appetite changes (I tend to get hungrier personally), and of course getting sleepy shortly after ingestion. It should be mentioned that while dopamine is a naturally occurring hormone in the human body, it is potentially habit-forming. As such, I would limit exposure to prami/caber for times when needed ONLY; such as during times of 19-nor usage.
My .02c