Alpha 2U-globulin: measurement in rat kidney and relationship to hyaline droplets

The concentration of renal alpha 2U-globulin increased in a dose-dependent manner in adult male but not female rats which received a single dose of 2,2,4-trimethylpentane (TMP). After administration of a single dose of 12 mmol TMP/kg to adult male rats, the renal concentration of alpha 2U-globulin reached a peak at 48 hours and returned to near background level after 7 days. These changes in renal alpha 2U-globulin concentration were closely paralleled by changes in renal hyaline droplet formation. Renal alpha 2U-globulin and hyaline droplets were absent in normal pre-puberty male rats, and neither could be stimulated by a single dose of TMP. alpha 2U-Globulin was localised in the renal cortex of adult male rats, in particular the S2 segment of the proximal tubule. A greater staining intensity due to alpha 2U-globulin was seen in the S2 and adjacent segments after a single dose of TMP. A strong association is suggested between the presence of renal hyaline droplets and the occurrence of alpha 2U-globulin.     

HRAS1-selected, chromosome-mediated transformants vary in phenotype in vitro and tumorigenic potential in vivo

Transfection of mouse C127 cells with mitotic chromosomes isolated from a human EJ bladder carcinoma cell line gave rise, at high frequency, to foci of transformed cells. Independent, HRAS1-selected chromosome-mediated transformants displayed distinctive cellular morphologies in monolayer culture and colony-forming abilities in low-melting-point agarose. Subcutaneous inoculation of neonatally thymectomized, Ara-C-protected, total-body-irradiated CBA mice was used to compare the tumorigenic potential of each transformant. Significant quantitative and qualitative differences in tumorigenicity were found between transformants which correlated with differences in malignant phenotype observed in vitro. The sensitivity of the tumorigenicity assay is such that rare transformation events can be selected directly in vivo.