Purification and properties of interstitial cell-stimulating hormone from sheep pituitary glands.

Early investigations on the purification and characterization of the hypophyseal interstitial cell-stimulating hormone yielded highly active products from sheep (l-3) and swine (4,5) pituitary glands. The preparations appeared to be homogeneous according to the physical and biological criteria of purity then available. The importance of the early ovine and porcine preparations is attested by the fact that most of what we know of the biological action of ICH’ was learned from studies involving the use of these early preparations, and yet it is probably fair to state that no practical method for obtaining the hormone in a state of purity that would satisfy modern criteria was available at the time that the present investigation was initiated; therefore, it seemed profitable to re-examine the problem of the purification of ICH, with use of purification procedures which have been developed since the earlier work and application of the newer criteria of purity. There evolved from this re-examination an improved purification procedure as well as new information concerning the physical, chemical, and biological properties of the hormone. In the course of these studies, we have obtained two chromatographically distinct fractions with high ICH activity. A brief outline of the essential steps in the purification procedure and some of the properties of one of the fractions, which was designated @-ICH, has already been presented (6). It is the purpose of this communication to present more complete experimental details? as well as data relative to yields and purity of fractions obtainable by the new procedure.