Cultivation in vitro of the testis cord of the newt, Triturus pyrrhogaster

Testis cords of Triturus pyrrhogaster were cultivated in vitro on (a) medium with chick embryo extract and calf serum, (b) medium with newt gonad extract, (c) Trowell 's medium T8 and (d) liquid synthetic medium 199. Of the four media utilized, medium 199 gave the best result for long-term maintenance of the normal histological structures of the testis cords. Addition of insulin (5 μ/ml) to medium 199 resulted in a remarkable improvement for the maintenance of the testis cord and the migration of columnar cells of the peritoneal epithelium into the primordial germinal tissue occurred as in the intact testis of this animal. Trowell 's medium T8 was proved inadequate. Medium with chick embryo extract and calf serum retained most of the germ cells healthy but caused gradual decrease in height of the columnar cells. Testis cords cultivated on the same medium in combination with Xenopus testis maintained normal histological structure for 18 days, whereas, those kept in contact with Xenopus ovary showed involution within the same period. Newt testis extract brought about transformation of somatic elements of the germinal tissue into fibroblastlike cells which was followed by the disintegration of germ cells. Ovary extract did not cause selective destruction on the somatic or germinal elements.