PREPARATION, BIOLOGICAL ASSAY AND PROPERTIES OF RELAXIN1

Abstract

Castrated [female] guinea pigs were given a daily dose of 0.83 [mu]g. of estradiol for 4 days, and a single inj. of relaxin on the 5th day. 6 hrs. following the relaxin inj., the symphysis pubis was palpated, and the % of animals showing relaxed pelves detd. A guinea pig unit of relaxin has been defined as that amt. of hormone producing relaxation of the symphysis in 2/3 of the animals. A simple and rapid method for the extraction and preliminary purification of relaxin from sow corpora lutea is described. One mg. of the prep., containing 15% of N, represented 1 guinea pig unit of relaxin. 120% mg. of the relaxin prep., representing 0.12 kg. of fresh tissue and 0.5 g., representing 1/2 kg. of fresh tissue, were negative for estrogenic and progestational effects, respectively.