title: Basis for the assay of myogenic cell growth in vitro using creatine kinase activity as an index, with special reference to measurement of power ratio of transferrins in growth promotion.
abstract: In order to establish an assay for the in vitro growth of myogenic cells, we investigated whether creatine kinase (CK) activity can be used as an index for the estimation of growth. The content of CK activity in a primary myogenic cell culture, almost all of which originated from myotubes, was shown to be linearly proportional to the content of proteins in the myotubes and increased concomitantly with myotube growth. CK activity can be easily and accurately assayed and used for routine assay of the cell growth. As an example of the application of CK activity for the bioassay of growth promoting substances, the relative potency (Pr) of turkey transferrin (Tf) to chick Tf in the promotion of chick myogenic cells was examined with a parallel line assay. The calculation limited that Pr = 0.363, ranging from 0.356 to 0.370, at 95% safety. The results demonstrated the usefulness of CK activity for estimating cell growth, as well as the value of a statistical method for the assay of a growth factor in vitro.
authors.affiliation: Division of Cell Biology, National Institute of Neuroscience, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hagiwara
authors.forename: T
authors.initials: T
authors.lastname: Shimo-Oka
authors.forename: K
authors.initials: K
authors.lastname: Okamura
authors.forename: E
authors.initials: E
authors.lastname: Ozawa
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002455:Cell Division; D002642:Chick Embryo; D003402:Creatine Kinase / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D024510:Muscle Development; D009124:Muscle Proteins / Q000032:analysis; D009132:Muscles / Q000032:analysis / Q000166:cytology; D013997:Time Factors; D014168:Transferrin / Q000494:pharmacology*
chemical_list: D009124:Muscle Proteins; D014168:Transferrin; D003402:Creatine Kinase