ANTIHORMONE PROPERTIES OF UREA-DENATURED SHEEP GONADOTROPIN

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Abstract
Unfractionated sheep pituitary gonadotropin, when subjected to aqueous 40% urea at 37.5 C, rapidly loses its gonadotropic properties so that at 6 hours'' treatment only 8% of the original activity remains. Further treatment in 40% urea leads to a gradual loss of potency. Sheep pituitary gonadotropin exposed to aqueous 40% urea for 8 hrs. at 37.5 C was subjected to 3 bioassay procedures, viz., the gonadotropic, antagonism and antihormone effects; 8 [plus or minus] 1.5% of the gonadotropic, 11 [plus minus] 1.5% of the antagonism and 63 [plus or minus] 13% of the antihormone effects were manifested by the denatured product. It is concluded that the multiple physiologic properties manifested by the sheep pituitary gonadotropic fraction are inherent in a single hormone, but that the specific properties are dependent upon the spacing of specific adsorption foci (secondary valence effects), which may or may not be displaced in denaturation. In the example cited, the gonadotropic and antagonist properties which are dependent upon the same foci are largely displaced, but the arrangement required for antihormone formation is largely retained.