Serological and Immunochemical Studies on the Gonadotrophic Hormones *

The question of the nature of antihormones and of the mechanism of the hormone-antihormone reaction has been a point of controversy for many years. The impetus for the numerous investigations carried on in recent years was provided by Collip who postulated the antihormone theory as a result of his experiments in 1934 and 1935. 4 Prior to this time, many workers were fully aware of the fact that some degree of refractoriness is developed with constant and prolo(nged administration of various hormones. Collip, however, in htis search for an explanation of this peculiar resistance, found that the sera of animals which did not respond to injections of gonadotrophic hormone protected immature, female rats against the normal action of the hormone. Collip and Anderson5 also demonstrated a simlilar result with the thyrotrophic hormone and, as a result of further investigation, found that other pituitary fractions were capable of stimulating the production of self-inhibitory substances. On the basis of their experimental evidence and as a guide to further work, Collip and his colleagues suggested a buffer system of hormones and antihormones which, under normal conditions, is maintained in a state of physiological equilibrium. "For each hormone there may be an opposite or antagonistic principle. This antagonist is present in the normal subject but may not be detected until it exceeds in amount the normal system with which it is buffered." Th.ompson14 agrees with Collip in the use of the term "antihormone," but interprets the word in an entirely different manner. Collip,8 in his use of the term, defines it as synonymous with the "chalone" of Sharpey-Schafer, whereas Thompson considers it to be consistent with immunological terminology. Since antitoxin is