Amphetamines reduce embryonic size and produce caudal hematomas during early chick morphogenesis.

Experiments were designed to study some of the similarities and differences in the effects of amphetamines and trypan blue on early chick morphogenesis. Both dextroamphetamine sulfate (0.5 mg/egg) and methamphetamine hydrochloride (1.0 mg/egg) were capable of inducing, in 3-day chick embryos, caudal hematomas which were similar in appearance and location to those routinely observed following treatment with trypan blue. It was found, too, that both dextroamphetamine and methamphetamine treated embryos frequently exhibited a significant decrease in crown rump length and cross-sectional area of the notochord, neural tube, dorsal aortae and whole body section, when compared with unopened or saline injected controls. Trypan blue treated embryos had only a rare decrease or increase in the size of structures when compared to either control group. These findings suggest that the amphetamines have an ability to decrease or retard embryonic growth in the chick.