(a)
(b)
(c)
Figure 1: in media conditioned by fibroblasts isolated from the lungs of young and old mice. Primary lung fibroblasts from young mice and old mice were cultured in one of 3 different redox media: oxidizing (0 mV), typical (−80 mV), or reducing (−150 mV). Media was removed immediately (0 hours) or after 24 hours and processed for determination of Cys and CySS concentrations and as described in Section 2. (a) Change in of 3 different redox media following 24-hour incubation with cells from young mice. (b) Change in of 3 different redox media following 24-hour incubation with cells from old mice. (c) Change in of 3 different redox media following 24-hour incubation in the absence of cells.