STRAIN VARIATION IN THE ASSAY OF FOLLICLE-STIMULATING HORMONE BY THE OVARIAN AUGMENTATION TEST IN MICE
ABSTRACT Assays of follicle-stimulating hormone from the National Institutes of Health (NIH-FSH-S4) and the Second International Reference Preparation for Human Menopausal Gonadotrophin (IRP-HMG) have been conducted by the mouse ovarian augmentation test in animals of nine strains from five mouse breeders. Two groups of 50 mice from each colony were used to assay NIH-FSH and the Second IRP-HMG. In the experiment with NIH-FSH dosages of 37.5 to 300.0 μg were given together with 40 IU human chorionic gonadotrophin (HCG) in three or five sc injections over three days. When the Second IRP-HMG was assayed dosages of 0.19 to 1.5 IU were administered in five injections with 20 or 40 IU HCG. Little or no ovarian weight increase occurred following NIH-FSH in six out of nine colonies. In the remaining three the index of precision (λ) was very high. Following administration of the Second IRP-HMG a greater increase in ovarian weight occurred but a satisfactory slope was noted in only three colonies. The λ figures were generally lower than with NIH-FSH. It is concluded, that under the conditions used, six out of the nine colonies were not suitable for the assay of FSH by the ovarian augmentation test. Further work would be required to study the reliability criteria of the assay in the remaining three colonies.