Direct evidence that IGF-I has any significant effect on embryo growth is lacking. We therefore studied the effect of administration of IGF-I on the chick embryo in ovo. Five hundred ng pure IGF-I (purified from human plasma) were given to chick embryos on 2 occasions (7 and 14 d) by injection directly into the allantoic sac. Treated and control (saline injected) chicks hatched on the same day ...

This study investigated whether the same cytochrome P-450 (P-450) isoenzymes were inducible in cultures of chick-embryo hepatocytes as in the liver of chicken embryos. We purified two isoenzymes of cytochrome P-450 from the livers of 17-day-old-chick embryos: one of molecular mass approx. 50 kDa induced in vivo by the phenobarbital-like inducer glutethimide, and the second of approx. 57 kDa ind...

It has been demonstrated that hypophysectomy decreased the rate of incorporation of radiosulfate into cartilage of rats and that the administration of growth hormone resulted in a remarkable rise of the uptake of labeled sulfate (Ellis et al., 1953;Denko and Bergenstal, 1955; Murphy et al., 1956). In order to clarify the mechanism of notable action of pituitary growth hormone on the growth of c...

Temperature-sensitive mutants of Sindbis virus were employed to investigate the nature of the viral event(s) which induces chick-embryo cells to produce interferon. Chick embryo cells induced by the parental heat-resistant strain of Sindbis virus produced essentially equal amounts of interferon at 29 and 42 C. An RNA(-) and three RNA(+) strains [temperature-sensitive mutants unable (RNA(-)) and...

UDP-glucuronyltransferase activity of neonatal-chick liver or phenobarbital-treated chick-embryo liver catalysed the glucuronidation of 1-naphthol, 4-nitrophenol and 2-aminophenol. Only low transferase activity towards testosterone was detected, and activity towards bilirubin was not detectable. Liver microsomal transferase activity towards the three phenols was increased approx. 20-50-fold by ...

Infection of stationary chick embryo fibroblasts by reticuloendotheliosis virus (REV) is sensitive to cytosine arabinoside, an inhibitor of DNA synthesis. Furthermore, the majority of the nucleic acid sequences contained in the REV genome can be detected in infected cells in the form of DNA by RNA-DNA hybridization techniques. A small portion (ca. 5%) of the REV-specific sequences can be detect...

We have made ten attempts to cultivate vaccine virus in tissue extracts prepared according to the method described by Eagles and Kordi (4). Renal, testicular, and chick embryo extracts were employed with a dermal strain of vaccine virus and with the Levaditi strain of neuro-vaccine virus. In no instance were we able to show that the virus multiplied in the extract media. Both of these strains o...

Cells of the Krebs ascites tumor of mice grow well in the body of the chick embryo until about the 17th day of incubation, when degeneration of the tumor can be seen in tissue sections and viable tumor cells begin to disappear from the internal organs of the embryo. This death of tumor cells follows the appearance in the chick embryo of serum gamma globulins. Among these are antibodies which ca...