Responses of serum calcium and inorganic phosphate levels, parathyroid gland and C cells of Rattus norvegicus to heptachlor administration.

Intramuscular administration of two doses: 0.50 LD50 (14.70 mg/kg b w) and 0.75 LD50 (22.30 mg/kg b w) of heptachlor in Rattus norvegicus for 14 days induced significant hypocalcemia without altering serum inorganic phosphate value. Parathyroid chief cells of the experimental rats exhibited degranulation, vacuolation, loss of secretory granules and lipid droplets, reduction in chromatin, and degenerative changes in endoplasmic reticulum and cristae of the mitochondria. Not much of histological and ultrastructural changes could be seen in C cells of the heptachlor treated rats.