Intracellular free magnesium concentration in healthy horses.
Authors: Winter J C, Sponder G, Merle R, Aschenbach J R, Gehlen H
Journal: Journal of animal physiology and animal nutrition
Summary
Magnesium plays a crucial role in insulin sensitivity, and whilst human research demonstrates clear benefits of magnesium supplementation in metabolic syndrome, serum magnesium measurements have proven unreliable for assessing true cellular status in both species. Winter and colleagues established the first reference ranges for intracellular free magnesium concentration in equine blood lymphocytes using mag-fura 2 spectrophotometry, measuring 12 healthy horses at three time points throughout the day and finding a mean concentration of 0.291 mmol/L (reference range 0.16–0.42 mmol/L)—slightly lower than healthy human values despite all horses having serum magnesium within conventional laboratory ranges. This methodological framework now provides equine practitioners and researchers with a sensitive diagnostic tool to detect altered cellular magnesium homeostasis in suspected equine metabolic syndrome cases, potentially identifying nutritional deficits that serum testing alone would miss and guiding targeted supplementation strategies where conventional indicators appear normal. Future research comparing intracellular magnesium concentrations between healthy horses and those with confirmed EMS will determine whether this measurement can serve as a reliable biomarker for the condition and help optimise nutritional management protocols for metabolically compromised animals.
Read the full abstract on PubMed
Practical Takeaways
- •Serum magnesium levels alone are unreliable for assessing a horse's magnesium status; intracellular measurement via mag-fura 2 spectrophotometry is needed for accurate diagnosis
- •This established reference range (0.16-0.42 mmol/L) for healthy horses can now be used to identify magnesium homeostasis alterations in EMS-affected horses
- •Given magnesium's role in insulin sensitivity, this diagnostic tool may help identify metabolic dysfunction earlier in horses at risk for or with EMS
Key Findings
- •Mean free intracellular magnesium concentration in equine lymphocytes was 0.291 ± 0.067 mmol/L with reference range of 0.16-0.42 mmol/L
- •No significant variation in free magnesium concentration across different time points (9 a.m., 12 a.m., 4 p.m.)
- •All horses had total serum magnesium within normal reference ranges despite potential variations in intracellular status
- •Intracellular free magnesium measurement is more sensitive than serum magnesium for assessing true magnesium status in horses