Ultrastructural and biochemical alterations in the livers from chick embryos maintained in shell-less culture.

ABSTRACT

Ultrastructural and biochemical studies were conducted on the livers from chick embryos maintained in shell-less culture up to stage 39 (Hamburger-Hamilton) and from control embryos developed in ovo up to the same stage. The ultrastructural characteristics of hepatic cells from the cultured embryos were similar to those found in the controls except that they contained many large lipid droplets and were almost devoid of lipoprotein granules normally associated with the Golgi complex and the smooth endoplasmic reticulum. These changes suggest the existence of alterations in the lipid metabolism. The livers from cultured embryos showed also a decreased incorporation of tritiated leucine into proteins, which indicates a reduced rate of protein synthesis. These results are consistent with previous reports showing that cultured embryos possess hypoproteinemia. Lactic dehydrogenase activity was similar and pyruvic kinase higher in the livers from cultured with respect to control embryos. This appears to indicate that both aerobic and anaerobic glycolysis were not depressed and that the changes observed in the rate of protein synthesis should not be attributed to hypoxia. "Fat-storing cells" similar to those described in mammals were found both in control and cultured embryos. They had not been previously described in the livers from chick embryos.