Effects of weight and sex of rabbits on the results of the testing of chorionic gonadoptrophin injection according to the European Pharmacopoeia

The test for pyrogens specified by the European Pharmacopoeia (1971, 1980) consists of measurement of the rise in rectal temperature evoked in rabbits by intravenous injection of a sterile solution of the substance to be examined. It is recommended to use ‘. . . healthy, adult rabbits of either sex weighing not less than 1500 g . . .’. It was observed in our previous work that reconstituted freeze-dried chorionic gonadotrophin (Gonadotraphon L. H . Paines & Byrne) gave irreproducible results when the tests were performed in groups of rabbits complying with the compendial criteria but otherwise selected on a random basis. A study of the effect of weight and sex on the test results was designed to investigate the causes of the irreproducible behaviour; a preparation of Gonadotraphon L. H. (1000 i.u.) which previously failed in a pyrogen test performed with a ‘random’ group of rabbits was used. In the new investigation, the animals were selected as follows: