An indirect assessment of the Chernoff/Kavlock assay.

The underlying principle of the Chernoff/Kavlock assay--namely that prenatal toxicity can be detected by means of simple postnatal endpoints--is strongly supported by experience gained in performing reproductive and developmental toxicity studies to international requirements. Compared with the supposedly more sophisticated procedures of regulatory tests, the simpler endpoints of the assay offer greater speed, economy, consistency and reliability. At the most, there is only a marginal loss of sensitivity in respect of detecting the lowest dosage at which effects may occur. The assay is best used as a concept rather than as a protocol with, "tailored" variations providing effective means of priority selection from a series of chemicals, especially analogue series. The underlying principle is applicable at levels through and beyond formal regulatory testing.