Metabolism of steroid estrogens in the hen II. Conversion in vivo of estradiol-17 α-4- 14C-17β- 3H to 17-epiestriol-4- 14C-17β- 3H and 16, 17-epiestriol-4- 14C-17β- 3H

• Published in: Steroids Vol. 12; no. 6; pp. 725 - 734
• Main Authors: Mathur, R.S., Common, R.H.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.12.1968
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/S0039-128X(68)80027-3

A mixture of estradiol-17 α-4- 14C and estradiol-17 α-17β- 3H was injected into a laying hen. The ratios dpm 3H:dpm 14C of the urinary radioactive estradiol-17 α and 17-epiestriol were practically identical whereas the corresponding ratio for the urinary radioactive 16, 17-epiestriol was considerably higher and approached the value for the injected estradiol-17 α. These results show (a) that the 17-epiestriol and 16, 17-epiestriol were derived directly from the estradiol-17 α and that estrone was not an intermediate product; and (b) that the formation of 16, 17-epiestriol was a relatively fast process. A general scheme for the pathways of in vivo derivation of the four estriol epimers in the hen is proposed on the basis of these and previous findings.