A HORMONE FOR GESTATION 



PREGNANEDIOL 



Pregnanediol is an inert substance as far as hormone action 

 is concerned. The body gets rid of it by attaching it to another 

 substance readily available from the starches and sugars of 

 the food, namely glycuronic acid (see Appendix, p. 253). 

 To this an atom of sodium is added, and the combined 

 substance, sodium pregnanediol glycuronidate, passes out 

 through the kidneys. It happens to be easily separable from 

 the urine and can thereafter be detected and measured by 

 relatively simple laboratory tests. Each molecule of this 

 waste product in the urine means that a molecule of pro- 

 gesterone was available for conversion. If ten milligrams, for 

 instance, of pregnanediol is recoverable from a single day's 

 urine, then we know the patient produced at least that much 

 progesterone — in fact a little more, for there is some loss in 

 the chemical process of measurement and possibly some loss 

 in the body, i.e. some of the progesterone may be broken down 

 and eliminated in other ways. The method is good enough, 

 however, to help very much in estimating the functional ac- 

 tivity of the corpus luteum in women and is beginning to be 

 used as a method of diagnosing ovarian deficiencies. 



All this information about the conversion and excretion of 

 progesterone unfortunately holds good only for the human 

 species and (apparently) the chimpanzee. It is enough to 

 make a laboratory experimenter tear his hair, when he realizes 

 that in other animals progesterone is excreted in some other 

 way, which nobody has been able to discover. Pregnanediol 

 has not been found in the urine of rabbits and monkeys, nor 

 in any other animal. Nor has any other substance that might 



{ 121 } 



