FENVALERATE-INDUCED ALTERATIONS IN CIRCULATORY THYROID-HORMONES AND CALCIUM STORES IN RAT-BRAIN

Intraperitoneal administration of fenvalerate, a synthetic pyrethroid, in male rats for 45 days in doses of 100 and 200 mg/kg body weight/da y induced hyperexcitability, tremors and paralysis. Tremors were obser ved after 7 days and gradually reached maxima on 45th day. The symptom s were more marked in rats treated with 200 mg/kg body weight/day. Fen valerate provoked significant elevation of circulatory thyroid hormone s, namely tri-iodothyronine (T-3) and thyroxine (T-4). A significant i ncrease in total calcium as well as protein-bound calcium in whole bra in and hypothalamus were recorded. The elevation of circulatory thyroi d hormones as well as the active calcium pool could be together respon sible for impairment of motor activity by altering various neuronal pr ocesses.