Non-steroid Ovariak Hormones

In 1950, Frieden and Hisaw (2) described a method for the isolation of relaxin from the ovaries of pregnant sows. This method, which involved extraction of ground whole ovaries with 5 per cent aqueous SaCl, fractionation with ethanol, and finally precipitation with acetone, afforded good yields (200 to 250 GPU’ of relaxin per gm. of fresh tissue), and material of saCsfactory potency (30 to 90 GPU per mg.). The method could be applied with equal success to acetone-dried ovarian powder. The salt-alcohol procedure possessed two major disadvant,ages: first, with either whole ovaries or acetone-dried powder, separation of the residue from the 5 per cent saline extract required a tedious centrifugation; second, the large volumes of solutions which ultimately resulted limited the amount of material which could be handled conveniently in most laboratories. From time to time during the past 6 years, efforts have been made to improve the extraction procedure, both as to quality of product and convenience of manipulation. A number of different solvents have been employed for the first extraction step, including water-saturated phenol, pyridine, and acid acetone; these methods generally afforded low yields of relaxin with no conspicuous improvement in handling or product. The technique of Payne et al. (3) of extraction with glacial acetic acid at 70” and then precipitation with acetone and ether gave excellent yields of relaxin from acetone-dried ovarian powder; the low potency of the final product, however, discouraged its further utilization. Good yields could also be obtained by extracting the powder with 6 M urea, fractionating the extract wit.h alcohol, and precipitating the relaxin with acetone; the product was, however, no more active than that obtained when salt solution was used as the initial extractant.