Dosage – Response Curves for the Teratogenic Activity of Trypan Blue

Abstract

A TERATOGENIC agent is one which, acting directly or indirectly on the developing organism, alters ontogenesis with consequent production of a malformed individual. In order to produce its characteristic effects the agent must be given within a specific dosage range, but this aspect of teratology is often neglected. Attempts have been made^1,2 to compare the teratogenic dose of certain substances with the adult LD₅₀ and recently the fœtal LD₅₀ has been considered useful³. This has led workers to relate embryo-toxic doses of drugs with their therapeutic dose⁴, and regression lines relating fœtal resorption to dose have been constructed for a number of drugs⁵. Here, dosage–response curves for the teratogenic dye trypan blue are constructed, and certain parameters relevant to teratogenic activity defined; these definitions may be widely applicable⁶.