Determination of the activity of clinical grade human growth hormone preparations by in vivo bioassay, in vitro cell proliferation assay and solid phase radioimmunoassay.
Preparations of clinical grade human growth hormone (hGH) have been examined for activity by an in vitro bioassay using NB2 lymphoma cells and by a monoclonal antibody (NA 71)-based radioimmunoassay. The activities observed have been compared with those obtained by the in vivo growth bioassay performed in mice of the Snell dwarf strain. The two in vitro assays correlated well with each other for specific preparations of hGH, although non-parallelism was observed between different preparations of the hormone. Some preparations of hGH were highly potent in the NA 71 immunoassay, but not in the NB2, cell-proliferation assay, suggesting the presence of antigenically active but biologically inactive hormone. Chromatographic studies on early hGH preparations revealed the presence of dimetric, trimetric and aggregated hormone as well as small quantities of prolactin. These were studied individually and shown to diverge in potency in the respective assays. It is concluded that the correlations between the in vivo bioassay in dwarf mice and the in vitro assays may be compromised by the varying potency of the constituent forms of the hormone and the non-linearity of the in vivo growth assay.
D000818:Animals; D000911:Antibodies, Monoclonal; D001681:Biological Assay; D002455:Cell Division; D013006:Growth Hormone / Q000032:analysis / Q000592:standards*; D006801:Humans; D051379:Mice; D008970:Molecular Weight; D011863:Radioimmunoassay; D013329:Structure-Activity Relationship
D000911:Antibodies, Monoclonal; D013006:Growth Hormone