THE GONADOTROPIC HORMONES 



and euglobulin fractions. The antihormone inhibiting the 

 action of the extract of pregnant-mare serum could not be 

 completely recovered; most of it appeared also to be asso- 

 ciated with the globulin fraction of serum. Zondek and Sul- 

 man (1937) have published several reports on biochemical 

 reactions between prolan and its antihormone. They con- 

 cluded that the antihormone is similar to an antibody. The 

 reaction between prolan and its antibody is reversible.'^ The 

 authors were unable to detect antihormone in tissues (liver, 

 spleen, muscle) or in the urine of animals whose serum con- 

 tained the substance. Biochemical differences between prolan 

 and its antihormone were also described."' 



The assay of prolan.^" — The remarks which were made in 

 chapter iii in reference to the assay of pituitary gonado- 

 tropic hormone apply with equal force to prolan. As soon as 

 suitable standards have been assayed by different technics 

 and the results evaluated, it will be possible to recommend 

 preferred assay technics. Among reports published recently 

 are those of Davy (1935), Korenchevsky, Dennison, and 

 Simpson (1935), Owen (1936), Morosowa (1936), and Kelly 

 and Woods (1937). Nelson and Overholser (1935), basing 

 their results on various criteria — i.e., opening of vaginal ori- 

 fice, oestrus, ovulation, follicular stimulation, luteinization — 

 estimated the relationship between the mouse-unit and the 

 rat-unit for several gonadotropic hormones to be as given in 

 Table 3. Their belief in the remarkable lack of potency of 

 prolan in the mouse as compared with the rat is in agreement 

 with most of the older reports. 



Levin and Tyndale (1937) found that the increase of uter- 



'* In one report the authors state that the antihormone destroys prolan. 



" Zondek and Sulman also studied biological effects of the antihormone of 

 prolan. Antihormone produced no effect after administration by way of the gastro- 

 intestinal tract. After subcutaneous injection, antihormone could be retained in the 

 body for several days. Also it could inhibit the effect of prolan, if injected 24 hours 

 after the hormone was administered. They regarded it as being both species and 

 organ specific (it did not antagonize the gonadotropic action of extract of blood of 

 pregnant women or of extract of the human anterior pituitary). 



^° See also chap. iii. 



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