FACTORS IN PANCREATIN WHICH INFLUENCE THE NUCLEOPROTEIN CONTENT OF FIBROBLASTS GROWING IN VITRO

• Published in: Experimental physiology 1944-09, Vol.33 (1), p.19-34
• Main Authors: Davidson, J. N., Waymouth, C.
• Format: Article
• Language: English
• ISSN: 0958-0670; 0033-5541; 1469-445X
• DOI: 10.1113/expphysiol.1944.sp000894

Material has been prepared from pancreatin which influences the growth of fresh explants of the 9-day chick embryo heart in roller-tubes. Cultures grown in a mixture of this material and embryo-extract show a much higher nucleoprotein phosphorus (N. P. P.) content than do control cultures grown in embryo-extract alone. They also have a characteristic dense compact appearance and are composed of well-nourished polyhedral cells with numerous mitotic figures. A method for the partial purification of the factor (or factors) responsible for these phenomena is described. It appears that at least two components are involved, one of which is responsible for the characteristic morphological changes in the cells, while the other can produce even in the absence of embryo-juice a very marked rise in N. P. P., as great as that produced under similar conditions by a very concentrated extract of embryonic tissue. Such nucleoprotein synthesis appears to be a necessary preliminary to cell division in cultures stimulated by the factor. This would be in accordance with the views of Willmer [1942 b, 1943]. Some chemical properties of the purified material are described. It appears to consist mainly of polypeptides and nucleotide derivatives. Crude preparations of lecithinase A from pancreatin and snake venom produce the morphological changes described, and this enzyme may be one of the active components. Our grateful thanks are due to Mr. E. N. Willmer of Cambridge and to Lt.-Col. W. F. Harvey of the Royal College of Physicians Laboratory, Edinburgh, for much valuable advice, to Dr. F. W. Landgrebe for photographic assistance, and to Dr. G. R. Barker and Messrs. Boots Pure Drug Co. for samples of snake venom. A grant for scientific assistance from the Medical Research Council and an expenses grant from the Carnegie Trust for the Universities of Scotland to one of us (J. N. D.) are gratefully acknowledged.