Changes of creatine concentration during development of chick embryo

Changes of creatine concentration during development of chick embryo. Acta physiol. pol., 1985, 36 (3): 208-215. Investigations were carried out on embryos of Star Cross chicken after 6, 8, 10, 12, 14, 16, 18 and 20 days of incubation. It was found that the concentration of total creatine increased from 0.18 to 0.67 mg/g of embryo weight. The increase of creatine concentration at the time of development of the embryo was proportional to the increase in nitrogen concentration, and the share of creatine nitrogen in the pool of total nitrogen was about 1% throughout the whole period of embryonal development and during the first two days after hatching. The amount of creatine in fresh egg and in the yolk sac of the newly hatched chicken was about 1.5 mg. It was estimated that chick embryos during their development synthesized, on the average, 18 mg (6 mMol) of creatine. The course of changes in creatine concentration in the developing chick embryo is very similar to the course of changes in the rate of heat production.