Pharmacological concepts and developmental toxicology.

This communication provides evidence to support the concept that developmental toxicants (teratogens) produce their effect by either interfering with or enhancing the time-dependent signal-response mechanisms within the embryo. Essential to this hypothesis is the need to show that an observed effect is a function of the administered dose, that there is a positive correlation between the observed effect and pharmacokinetic parameters and that there is evidence for the existence of a specific receptor for the toxicant. While extensive effort is required for ultimate validation of this concept, it serves to emphasize the value of applying known pharmacological principles in defining a mechanistic framework for the biological activity of developmental toxicants.