How does bromocriptine affect insulin resistance?

Helps. Bromocriptine is usually used to reduce elevated prolactin levels made by the brain, but recent studies have indicated that it may also improve glucose tolerance, hence decrease Insulin resistance.
It's possible. Bromocriptine is a Dopamine agonist that lowers serum prolactin that is responsible for lactation. In women with high prolactin, it may help ovulation, improve implantation. Compelling literature (animals) suggest that lack of Dopamine may induce Insulin resistance and may reduce arterial fatty uptake and shift to carb uptake. Thus, its possible bromoriptine may enhance Insulin sensitivty.