| Comments |
P.708 left column bottom paragraph: "Growth-related changes in oxygen consumption: It is natural to assume that cells will have different OCRs (oxygen consumption rates) depending on their growth state and metabolic demand, i.e., exponential growth vs quiescence or differentiated cells. Rapidly growing (exponential) mammalian cells consume oxygen at greater rates than observed when in plateau phase (Table 3). These examples have changes that range from a 1.5- to a 5-fold increase in OCR. Interestingly, cells in lag phase apparently can in some circumstances consume oxygen at rates greater than when in exponential growth. A process that occurs during lag phase is adjustment of the extracellular redox environment (refs [63], [64], [65]). Adjusting the redox status of extracellular thiols would require considerable flux through the pentose cycle and thus a large demand for ATP and possible need for dioxygen. However, the OCR in various phases of the cell cycle and growth needs more detailed studies to provide clear knowledge of these associations." |