Maintenance of proximal and distal cell functions in SV40-transformed tubular cell lines derived from rabbit kidney cortex

This paper reports the preparation and describes the properties of three renal tubular cell lines derived using SV40 infection of primary cultures of rabbit kidney cortical cells, enriched in proximal cells. RC.SV1 was initially derived from cultures grown in the presence of fetal calf serum exhibiting a low degree of proximal differentiation. The cells were subsequently adapted to grow in serum-free hormonally defined medium and display basic properties of proximal tubule cells including well-developed apical microvilli, strong expression of brush-border hydrolases, Na+-coupled glucose uptake, and increased cyclic AMP production when exposed to PTH. The other two cell lines were derived from cultures in serum-free hormonally defined medium and propagated in the same medium. They are characterized by some common properties including rare and short microvilli, low expression of apical hydrolases, and low or undetectable Na+-dependent glucose uptake, but differ by their abilities to respond by an increase in cAMP to various hormonal stimuli. RC.SV2 cells are sensitive to calcitonin and to a lesser extent to isoproterenol and PTH, suggesting that they may originate from the thick ascending limb of Henle's loop and the bright portion of the distal tubule. RC.SV3 responds essentially to isoproterenol and arginine vasopressin, suggesting a more distal origin (late distal and initial collecting tubule). Emergence of distal cell lines from cultures exhibiting proximal characteristics may be related to distal cell overgrowth as suggested by analysis of growth kinetics and increased Na+/H+ exchanger activity in RC.SV2 compared with RC.SV1.