Long-term treatment of insulin insensitive mares with cabergoline: Effects on insulin sensitivity, insulin response to glucose infusion, and prolactin response to sulpiride

Prolactin in the Horse: Historical Perspective, Actions and Reactions, and Its Role in Reproduction

“…In a study with similar results (no effect on first ovulation), Oberhaus et al [53] used a long-acting dopaminergic compound, cabergoline, in every-10-day injections in a slow-release vehicle to suppress prolactin concentrations in mares starting on February 4. Identical injections of cabergoline had been previously shown to suppress prolactin secretion and the prolactin response to low-dose sulpiride injections for at least 10 days [54,55]. For comparison, administration of 2 mg of pergolide, another dopaminergic compound commonly used to treat pituitary pars intermedia dysfunction in horses [56], reduced plasma prolactin concentrations in geldings for only 6 hours when given PO and only 24 hours when injected intramuscularly in a slow-release vehicle formulation [54].…”

“…During the autumnal transition period, suppression of prolactin secretion in mares with every-10-day injections of cabergoline [55] from September to November initially caused an approximate 25% increase in hair shaved from the shoulder in the first 30 days. However, because of the naturally rising increase in hair growth of the control mares and an apparent plateau of hair growth in the cabergoline-treated mares, the effect was reversed after 61 days of treatment.…”

Equine obesity: current perspectives

“…Despite a recent questionnaire survey of equine veterinary surgeons indicating that 20% used pergolide for the management of EMS (Menzies-Gow, 2012), there is no indication for its use in the management of obesity or EMS in the absence of PPID. While it had been suggested that pergolide might have an insulin sensitising effect, a recent investigation determined that dopamine agonists do not increase insulin sensitivity (Valencia et al, 2013). Various nutraceuticals have been suggested to be of benefit in the management of obesity and particularly EMS, but there is insufficient scientific evidence to justify their use.…”