[Study of the potential carcinogenic activity of reserpine]

A single dose of 2.5 mg/kg body of reserpine was injected subcutaneously (once a week) or given per os (2-5 times a week) to 100 rats and 100 mice of local breeding throughout their life-time. Another 100 rats and 100 mice in control received only sunflower oil used as a vehicle. Tumor incidence rates were 34.6 (sc injection), 40 (per os) and 7.8% (control). The differences in the percentage values were significant. Tumor frequency in mice for subcutaneous and oral treatment was 24 and 43%, respectively, which was significantly higher than in controls (6.3 and 10%, respectively). Experimental animals revealed a tendency towards a shorter period of tumor latency. Rats developed mostly pheochromocytoma of the adrenals, whatever the route of administration, mice-mammary neoplasms. Other localizations of tumor were also found. The results point to reserpine's slight carcinogenic effect on rats and mice.