Thyroidectomy and thyroxine administration alter serum calcium levels in rat.

The effects of thyroidectomy and thyroxine on serum calcium concentration were studied in adult albino Wistar strain rats using the technique described by Baginski et al. (1973) as used by Lorentz [10]. Thyroidectomy decreased serum calcium concentration from 2.28 +/- 0.02 mmol/l to 1.61 +/- 0.01 mmol/l. Chronic administration of thyroxine (6-8 micrograms/100 g body wt/day) for 35 days caused an increased serum calcium concentrations from 2.28 +/- 0.02 mmol/l to 2.98 +/- 0.05 mmol/l. These findings suggest that thyroidectomy and the dose of thyroxine used affected calcium metabolism in rats.