AN EXPERIMENTAL STUDY ON α-FETOPROTEIN PRODUCING YOLK SAC TUMOR

Abstract

It is known that testicular teratocarcinomas occur spontaneously in mice of strains 129 and they produce α-fetoprotein (AFP). But AFP producing teratocarcinomas in rats are not yet established.
This is a report on experimental induction of teratomas containing yolk sac tumors in rats and serum AFP levels of these rats. The experimental procedures and results are as follows:
Group 1: Pregnant rats of strains Donryu mated with Donryu males were fetectomized at 12 days of gestation, and the fetal membranes were pulled out into the peritoneal cavities. After 3 or 4 months extra-uterine tumors, histologically teratomas, developed in 11 of 15 rats. High serum AFP levels were obtained in 4 rats with teratomas containing the elements of yolk sac tumors.
Group 2: Pregnant Donryu rats mated with Donryu males underwent the samee procedure, but were inoculated with murine sarcoma virus (Moloney) into the remained placentas. Teratomas developed in 18 of 19 rats, and 4 with tumors containing yolk sac tumor elements were shown to have high concentration of serum AFP.
Group 3: Pregnant rats of strains WKA mated with WKA males were operated on with the same procedure as in group 2. Teratomas occurred in 2 3 of 31 rats, and 12 rats which had yolk sac tumor components demonstrated high levels of serum AFP.
Group 4: Pregnant Donryu rats mated with WKA males underwent the same procedure including virus inoculation. All 10 rats did not have any tumors nor showed any elevation of serum AFP.
Group 5: Non-pregnant WKA rats were inoculated with murine sarcoma virus (Moloney). None developed tumors and showed high levels of serum AFP. Teratomas containing yolk sac tumors were succesfully transplanted into syngeneic young adults by intra peritoneal trocar implantation.
Histological findings of the experimentally induced tumors and AFP production were discussed in relation to multipotentiality of yolk sac cells.