STEROID HORMONES AND AGING IN MAN 411 



directly from labeled cholesterol in adrenal tissue preparations have 

 led to only very small yields ( Bloch et al., 1957 ) . 



Our studies of estrogen excretion demonstrated: (1) that the total 

 biological activity excreted into the urine appeared to be relatively 

 constant for normal, healthy men throughout the decades studied; (2) 

 that outputs among women declined from a level roughly three times 

 that of men in the third decade to the output level of the men by the 

 sixth decade and a constant excretion rate thereafter; (3) that the 

 biological activity in estradiol and estrone fractions declined with ad- 

 vancing age in both men and women, but in men there was an average 

 tendency for estriol fraction activity to increase, and this was paralleled 

 in the women's data only from the seventh decade on. 



From these data on estrogen excretion we concluded, first, that the 

 marked output decline in women to post-menopausal decades indi- 

 cated a decline in ovarian-estrogen biosynthesis; and, secondly, that in 

 men, testis plus adrenocortical biosynthesis acted, to maintain a fairly 

 constant level, but the conversion of the biologically more active estro- 

 gens, estradiol and estrone, to the less active estriol tended to be in- 

 creased with advancing age. 



Recently in certain groups of subjects we have re-examined steroid 

 excretion, usually employing somewhat different methods of measure- 

 ment. I should like to present first of all data oil corticosteroid, 17-ke- 

 tosteroid, and estrogen outputs in urines from a group of men aged 28 

 to 71 who are being followed for a period of years. In contrast to the 

 acid hydrolysis previously employed, we have used enzyme hydrolysis 

 to liberate the steroids from their conjugated excretion forms. The 

 chromatographic separation of the 17-ketosteroids on paper, and of the 

 estrogens by the method of Bauld ( 1956 ) , have been practiced. 



In Table I are the mean data for the neutral steroids of 308 urine 

 samples from these men. When these data are plotted according to 

 median age, it is possible to calculate the percentage decline in output 

 over the 40-year period from age 30 to age 70. It will be seen that the 

 maximal declines in output occur in the ll-deoxy-17-ketosteroids, and 

 that among these the dehydroepiandrosterone decrement is the largest 

 (about 16 per cent per decade). The total 17-hydroxycorticosteroid 

 output is slightly diminished (about 3 per cent per decade) and the 

 ll-oxy-17-ketosteroid output rate seems to be just about constant. 



In Table II are the data for estrogen excretion for the same sub- 

 jects. The marked average decline in output of the more active estro- 

 gens ( about 14 per cent per decade ) clearly exceeds the decrement in 

 estriol excretion (about 4 per cent per decade). These data agree 

 partially with those obtained previously by bioassay of these fractions 

 differently separated; the previously noted estradiol and estrone de- 

 cline is seen but is quantitatively greater here, and the previously noted 



