SKELETAL MALFORMATIONS INDUCED BY THE INSECTICIDES ZZ-APHOX(R) AND FOLIDOL(R) DURING LARVAL DEVELOPMENT OF RANA-PEREZI

Tadpoles of Rana perezi were kept for 14 weeks in water containing two sublethal levels of the carbamate insecticide ZZ-Aphox(R) or the orga nophosphate Folidol(R). Approximate concentrations of their active ing redients were 0.25 and 1 mg/L. Resulting malformations were studied by skeletal analysis and histological and histochemical investigation of the rear limbs of the tadpoles. The pesticides caused the animals to have malformations of the spinal column (scoliosis) and/or limbs (shor t and thick long bones with the epiphyses grossly twisted). Histochemi cal study showed differences in the composition of the connective matr ix, and microscopic examination of the long bones indicated alteration s in the thickness of the uncalcified bone matrix (osteoid) and the pr esence of abundant vascularised connective tissue in the region of the periosteum. The results confirmed changes in the composition of the c onnective tissue matrix as the cause of the defects observed in bone f ormation which are also discussed in relation to vitamin D absorption and calcium homeostasis.