Inhibitory Effects of Pergolide and Cabergoline Formulations on Daily Plasma Prolactin Concentrations in Geldings and on the Daily Prolactin Responses to a Small Dose of Sulpiride in Mares
Journal of Equine Veterinary Science Article in press published online 18 Feb 2013
An injection of 2 mg pergolide in a slow-release vehicle reduced prolactin secretion in geldings for 6 - 24 hours, compared to 6 hours or less when 2 mg pergolide was given orally. An injection of 5 mg of cabergoline in a slow release vehicle reduced prolactin secretion for at least 6 days. The research concluded that both daily injections of 2 mg pergolide or a single injection of 5 mg cabergoline (both in slow-release vehicles) effectively applies dopaminergic activity to horses for 7 - 10 days, and that this may be useful in the treatment of PPID.
PPID affects the pars intermedia, prolactin is secreted by the pars distalis, so further research would be needed to verify the effects of these treatments for PPID.