Summary. A number of horse chorionic gonadotrophin (CG) preparations of different purities and from diverse sources have been compared in radioimmuno-, radioreceptor, in-vitro cell culture, and in-vivo assays. The relative activities of the great majority of the preparations tested were consistent in the 4 assay systems. Moreover, their relative activities in the 4 assays were consistent with those found for unfractionated plasmas. These preparations were therefore considered to represent the native form of hormone.
The second International Reference Preparation (IRP2) was among the few preparations exhibiting discordant relative activities in the different assay systems. Its relative in-vivo activity was almost 50% lower than that found in the 3 other assays. This could be due to denaturation of the hormone during its preparation or to selection of isoform(s) not representative of the whole population of molecules.
For standardization of horse CG preparations by in-vivo assay, IRP2 has proved to be a reliable standard. However, for the standardization of preparations by in-vitro methods, a standard giving consistent results in in-vivo and in-vitro assays must be used. The present report indicates that the NIH standard, but not IRP2, fulfils these requirements.
Reproduction is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
Sept 2018 onwards | Past Year | Past 30 Days | |
---|---|---|---|
Full Text Views | 111 | 21 | 1 |
PDF Downloads | 76 | 23 | 1 |