Thyroid hormone stimulates progesterone release from human luteal cells by generating a proteinaceous factor

Specifications are the regulatory and legal standards that a product must meet to be suitable for use in humans. Specifications evolve in parallel with drug development and are refined prior to marketing authorization and, in some cases, after marketing. Recent changes in regulatory procedures for biotechnology-derived protein products have placed much emphasis on the use of characterization and final product specifications to provide assurance of overall quality of these products. In addition, harmonized guidelines for the testing and specifications for biotechnology products have been developed through the International Conference on Harmonization process. The availability of sensitive, quantitative, and specific analytical methods for characterization has made this possible, thus providing regulatory flexibility in the development of biotechnology-derived protein products. Further refinement of these analytical tools will undoubtedly enhance this regulatory flexibility.