Effect of phenylbutazone on insulin secretion in horses with insulin dysregulation.

The research study investigated how the drug phenylbutazone, used for pain relief in horses, affects insulin secretion in horses diagnosed with insulin dysregulation. The study found that phenylbutazone decreased glucose and insulin concentrations in such horses, suggesting potential therapeutic uses beyond pain management.

Research Methodology

• The study involved sixteen light breed horses, seven of which had insulin dysregulation (ID).
• The research design was a randomized cross-over study. This means the horses underwent treatment with phenylbutazone (a nonsteroidal anti-inflammatory drug) or a placebo, followed by a washout period and then the alternative treatment.
• Each horse was subjected to an oral glucose test (OGT) after nine days of either phenylbutazone treatment (administered intravenously at 4.4mg/kg every 24 hours) or a placebo (5mL 0.9% saline).
• Analyses of variance and t tests were used to compare insulin and glucose responses between the groups (ID horses and controls) and the treatments received, considering P values less than 0.05 as statistically significant.

Research Findings

• In the horses diagnosed with ID, phenylbutazone treatment demonstrated a significant decrease in glucose and insulin concentrations in response to an OGT.
• Specifically, the glucose area under the curve (measurement that quantifies the overall glucose concentration over time during the OGT) reduced from 2847 to 2429 mmol/L x min, and the insulin area under the curve fell from 22,930 to 17,710 μIU/mL x min.
• No significant effect of phenylbutazone or the placebo was observed in the control horses (those without ID).

Conclusions and Implications

• The study showed that the administration of phenylbutazone in horses with ID decreases both glucose and insulin concentrations following an OGT. This outcome deviated from the initial hypothesis that phenylbutazone would increase insulin secretion.
• The findings indicate a potential therapeutic value for phenylbutazone in managing hyperinsulinemia-associated laminitis, an inflammation of certain foot tissues in horses often linked to high insulin levels and typically addressed through pain relief.
• However, further research is needed to conclusively determine the viability of using phenylbutazone for this secondary purpose.