X. KFFKCTS OF Dl'-Flfl i:\( V 



G09 



proj2;est(M'()ne is followed Uy suhslaiit iai iiihihilion of Ihc yjiowlli of the 

 {ionital ti'act, without aii\' dcprcssioii in plasma hiotiii act i\it_\'. Siinultaiie- 

 ously, a\i(liii production hccoincs apparent in chicks t icatcd with ,still)cstr<)l 

 and prot»ester()ne (see Table XII). "Tlic lolc of such metal)olites as l)iotiii 

 and avidin in tlie mechanism of hormone induced tissue-<i;i"o\vth remains a 

 challenging enigma."' 



Kfkkct ok Stii.bkstrol and Stii.bkstuoi, i'l.rs fuociKsriouDNK ().\ 15IOTIX Levels 



IN Cm UK Plasma 



" Injpotpd subcutaneoiKsly with 0.25 mg. of stilbestrol in 0.2 ml. of corn oil (biily for S days. 



' Injected subcutaneously with 0.25 mg. of stilbestrol in 0.2 ml. of corn nil and 1.0 mg. of progesterone 

 in 0.2 ml. of corn oil daily for 8 days. 



'' Values expressed as millimicrograms of biotin per milliliter of undiluteil plasma (in microbiological tests 

 on L. casei). 



(— ) signifies le.ss than and (+) more than, 0.1 unit of avidin per gram of oviduet (wet weight). .\ unit 

 )f avidin is the amount required to inhibit comi)lotely tlie yeast growth sujiported by 1 y of biotin. 



K. JilO'ldX AND CANCER 



I{ai)idly growing tissues, sueh as embiyonic tissue and cancer, are in 

 general low in hiotin. In careful studies West and Woglom'-' • '•' compared 

 the biotin content in \ai-ious tissues and oi'gans, obtained from adult 

 animals, from embryos, and tumors. Their findings are summarized in 

 Table XIIL 



In most cases studied, the tumor, as well as the embryonic tissues, con- 

 tained significantly less biotin than the corresponding tissues in adult ani- 

 mals. In a few cases, such as rabbit skin and connective tissue, the biotin 

 content in adult animals was higher than in the embryo or in tumor tissue 

 originating from the skin or connective ti.ssue. Rat hepatoma is also low 

 in biotin, compared with the high biotin content of iioiinal liver tissue.^^ 



" H. Hertz, F. G. Dhy.so, ;ni.l W. W. 'I'ullnci-, luHlocrincloyi/ 4:5, 451 (1949). 

 "^ P. M. West and W. 11. VVogloin, ^Science 93, 525 (1941). 

 " P. M. West and W. H. Woglom, Cnnrer Re-Search 2, 324 (1942). 



'6 M. A. Pollaclv, A. Taylor, A. Woods. ]{. C. Tliomi)son, .-iiid 1{. .1. Williams, Cancer 

 Research 2, 748 (1942j. 



