Muscular spasms and death in thyroparathyroidectomized rats subjected to pinealectomy

If rats were thyroparathyroidectomized when 24 to 25 days of age and were later (10 to 21 days) pinealectomized, all animals experienced severe convulsive attacks and most of them died within 14 hours. Sham thyroparathyroidectomized rats that were subjected to pinealectomy exhibited no similar convulsive episodes nor did they die. Thyroparathyroidectomy caused the anticipated decrease in serum calcium levels but had no influence on serum sodium, potassium or magnesium concentrations. Pinealectomy was followed by a slight elevation in serum potassium levels regardless of the status of the thyroparathyroid gland complex. Pineal removal did not influence the serum levels of either sodium, calcium or magnesium.