A possible hormone controlling O2 consumption in the nematode Phocanema decipiens

The third-stage larva of Phocanema decipiens, which initiates development upon transfer from 5 to 37 degrees, has been used in these experiments. Larvae ligatured at both the head and tail ends lose weight more rapidly during the first 4 hr after transfer to 37 degrees than do normal worms or those ligatured at the front end alone. Larvae ligatured at the tail end exhibit a higher rate of O2 consumption as determined manometrically than do normal larvae. The O2 consumption of strips of body wall is depressed by the addition of an homogenate of the posterior ends of worms, but unaffected by the addition of an homogenate of the anterior ends. These facts are consistent with the release from the tail end of the worm of a hormone which depresses the O2 consumption of the worm.