Heterogeneity in superoxide production as measured by nitro blue tetrazolium reduction from individual PAM

K. A. DiGregorio, E. V. Cilento, R. C. Lantz

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Heterogeneity in superoxide (O2-·) production (as determined by the reduction of nitro blue tetrazolium to a diformazan precipitate), cell volume, and cell spreading were measured from single rat pulmonary alveolar macrophages (PAM). Of the 330 cells that produced O2-· due to stimulation by adherence, the maximum diformazan produced (MAX) varied between 1.8 and 47.2 fmol and the maximum (initial) rate of diformazan production (R) varied between 2.2 and 81.7 x 10-3 fmol/s. Only six PAM of 336 analyzed failed to produce O2-· suggesting that O2-· production is not a specific function of a small subpopulation of PAM but rather that all PAM are capable of producing O2-·. Importantly, O2-· production by single cells showed extensive heterogeneity that did not correlate (r2 < 0.12) with individual cell volumes, suggesting that the observed heterogeneity may not be due to differences in maturation and/or differentiation. However, when the single cell data were grouped into cell volume subfractions small but increasing linear trends (r2 > 0.81) in MAX and R were found. This discrepancy suggests that PAM heterogeneity in O2-· fraction cannot be estimated adequately by measurements on subpopulations of cells.

Original languageEnglish (US)
Pages (from-to)L464-L470
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number6 4-3
StatePublished - 1991


  • Long-Evans hooded rats
  • Single cells
  • Superoxide release

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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