Centrifugation of 2 g does not affect otoconial mineralization in chick embryos

Chick embryos were grown on a rotating centrifuge for periods of 2 wk to study the effects of increased gravity on the relative growth of their otoliths and femurs. Embryos, 20-21 days of age, centrifuged at 2 g showed no difference in utricular otoconial CaCO3 weights and femur CaPO4 weights compared with stationary control embryos of the same age. In addition, control embryos rotated at the center of the centrifuge had otoconial CaCO3 weights and femur CaPO4 weights not significantly different from stationary controls or from embryos rotated at 2 g. Accordingly these data do not support the hypothesis that the weight of the embryonic otoconial membrane is involved in the feedback regulation of its growth.