Detection of the Multiple Forms of Human Growth Hormone

Abstract

It was not until the introduction of gel electrophoresis that the heterogeneity of preparations of growth hormone was uncovered. Prior to that time, moving boundary electrophoresis in the Tiselius apparatus was the most discriminating method for resolution of protein mixtures (1). A comparison of the resolving power of the Tiselius method with that of gel electrophoresis for separating components of bovine growth hormone can be found in an early paper by Lewis (2). The moving boundary technique only suggested heterogeneity by the nonsymmetry of the protein peak whereas by the polyacrylamide gel disc electrophoresis method of Ornstein and Davis (3,4), three well-separated components were detected. Before the use of polyacrylamide, starch gel was used as the supporting medium. Starch gel was difficult to work with but excellent resolution of components of human GH could be demonstrated as shown by Wallace and Ferguson (5). With the introduction of disc electrophoresis with its simple polyacrylamide gel formation technique, the reports dealing with the heterogeneity of preparations of pituitary proteins multiplied enormously. The technique owes its resolving power to separations on the basis of both charge and molecular size. The method is also versatile with regard to the ability to choose a wide range of pH values for the electrophoresis (6).