Growthanddifferentiation ofpluripotent embryonal carcinoma cells intheSnell dwarf mouse

SummaryToinvestigate theinfluence ofhormones on theprocessofcellular differentiation thegrowth and differentiation ofa transplantable tumour, induced byinoculation ofpluripotent mouseembryonal carcinoma (EC)cells havebeenstudied inathymic nudemiceand,normalandhypopituitary Snelldwarfmice.All athymic nudemicedeveloped tumoursindependent ofthenumbersofcells inoculated. Incontrast, the tumourpercentage innormalSnell micewas lower, showing a dose-dependent increase oftakes. Indwarfs tumourpercentage was comparable withthatobserved innormalSnell mice. Themorphological differentiation ofteratocarcinomas grown inathymic nudemice, normalanddwarfed Snell miceshowsderivatives ofallthree germlayers nexttoundifferentiated embryonal carcinoma cells. This suggests thatthepituitary hormonal deficiencies ofthedwarfs (growth hormone, thyroid stimulating hormone andprolactin) didnotinfluence thetumourinduction nor thedevelopment ofthedifferent tissues present in this typeoftumour. Theinfluence ofthepituitary on induction and growthofseveral neoplasms hasbeenstudied in hypophysectomized ratsand mice,and in