Hematologic and clinical chemistry effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin in laboratory animals.

Chlorodibenzo-p-dioxins, especially 2,3,7,8tetrachlorodibenzo-p-dioxin (TCDD), are among the most toxic compounds known. These compounds are found as contaminants of technical chlorophenols and their derivatives. A variety of pathologic condition have been associated with the injestion of products containing chlorodibenzo-p-dioxins. Toxic fat, the cause of chick edema disease (1, 2) and a variety of pathologic manifestations in monkeys (3), has been found to contain chlorodibenzo-p-dioxins, among which is TCDD (4, 5). TCDD has been implicated in a variety of other toxicoses, including outbreaks of chloracne in chemical workers (6), hepatonecrosis in rabbits (6), and hepatonecrosis and thymic atrophy in rats (7). However, only in the studies in which monkeys were fed toxic fat (3) and in which rats were given TCDD orally (7, 8) were substantial clinical pathologic analyses performed. Toxic fat caused in the monkeys, among other lesions, anemia, leukopenia and hypoproteinemia. The hypoproteinemia was primarily due to decreased serum albumin concentration. The blood urea nitrogen