THE RELATIVE ACTIVITY OF LATHYROGENIC AGENTS EXAMINED IN ORGAN CULTURES OF EMBRYONIC CHICK TIBIOTARSI EXAMPLE OF AN ASSAY USING PAIRED ORGANS IN AN INCOMPLETE BLOCK DESIGN

The effects of three commonly used lathyrogenic agents, methyleneaminoacetonitrile, beta-aminopropiobitrile and aminoacetonitrile, have been compared in vitro on chick embryo tibiotarsi in three replicated six-point assays using a balanced incomplete block design. MAAN and BAPN have parallel dose-response lines for all of the responses measured. Thus the relative potency of these preparations was calculated. Both have an equal effect on the elongation of the explanted chick bones but MAAN has a greater inhibitory effect on the weight gains by the bones. The dose-response lines for AAN are flatter than those for MAAN or BAPN and were not parallel to those for the other agents. Therefore, AAN could not be readily compared in terms of potency to the other lathyrogenic agents. The biological significance and the problems of comparing the relative activity of lathyrogenic agents are discussed.