STUDIES ON THE ASSAY OF PITUITARY GONADOTROPINS USING THE AUGMENTATION REACTION

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Abstract
In studies on over 1000 rats the variation of ovarian wt. with dosage in immature rats was studied, using dried human, horse, sheep and pig pituitaries. Chorionic gonadotrophin, sheep FSH and various combinations of the latter 2 gonadotrophins. The ovarian wts. were plotted against the logarithm of the dose of either chorionic, FSH, or combinations thereof, and regression lines of characteristic slopes were passed through the exptl. points. The slopes of such lines were a function of the relative proportions of FSH to LH or to chorionic in the sample tested. When FSH dosage was kept constant and chorionic dosage was varied, after an early rise in ovarian wt. a region of no change of ovarian wt. with increasing chorionic dosage occurred between dose levels of 1 to 10 I.U., irrespective of the FSH level. At higher dosage levels of chorionic than 10 I.U. the ovarian weight again increased rapidly. This circumstance makes possible the accurate assay of FSH potency by the combination of the pituitary fraction under test with 3 I.U. of chorionic gonadotrophin. Dried human pituitaries, plasma from a pregnant woman and chorionic gonadotrophin all behaved similarly in showing great augmentation when combined with 1 R.U. of sheep FSH and little or no augmentation when combined with chorionic gonadotrophin.