Calcium and Magnesium Regulation

Closeup of horse eyeDisorders of calcium and magnesium regulation are frequent in critically ill horses and foals. Both hypocalcemia and hypomagnesemia are associated with neuromuscular dysfunction, excitability, ileus, cardiac arrhythmias, and death in horses. For the past 10 years we have been actively working in this field, in particular on parathyroid hormone (PTH) and calcitonin physiology and pathophysiology. Important discoveries have been made (see selected publications). We have found that horses with gastrointestinal diseases often develop severe calcium and magnesium derangements result of low PTH concentrations (parathyroid gland dysfunction). In septic foals, we discovered that abnormally high PTH concentrations were associated with mortality. Sepsis is the number one cause of foal mortality. Our results have provided insight on the endocrine aspects of diseased horses and foals.

Selected Publications

  • Toribio RE, Kohn CW, Rourke KM, Levine AL, Rosol TJ. Effects of hypercalcemia on serum concentrations of magnesium, potassium, and phosphate and urinary excretion of electrolytes in horses. Am J Vet Res. 2007;68:543-554.
  • Toribio RE, Kohn CW, Hardy J, Rosol TJ. Alterations in serum parathyroid hormone and electrolyte concentrations and urinary excretion of electrolytes in horses with induced endotoxemia. J Vet Intern Med. 2005;19:223-231.
  • Toribio RE, Kohn CW, Leone GW, Capen CC, Rosol TJ. Molecular cloning and expression of equine calcitonin, calcitonin gene-related peptide-I, and calcitonin gene-related peptide-II. Mol Cell Endocrinol. 2003;199:119-128.

Insulin resistanceDiagram of Calcium and Magnesium Regulation