Liver mtDNA (LU/ng total patas DNA, mean ± SE) determined by HC-CA. (A) Patas offspring taken at birth after in utero exposure to no drug (n = 5), 3TC (n = 4), AZT/3TC (n = 3), AZT/ddI (n = 3), or d4T/3TC(n = 3). There were no significant differences between the unexposed group and any of the NRTI-exposed groups by one-way ANOVA. (B) Patas offspring taken at 1 year of age after in utero plus 6 weeks post-birth exposure to no drug (n = 4), AZT (n = 4), AZT/3TC (n = 4), AZT/ddI (n = 4), and d4T/3TC (n = 4). Differences between unexposed and NRTI-exposed groups were significant (p < 0.001) by one-way ANOVA. By the Holm-Sidak procedure for multiple comparisons, all the NRTI-exposed groups (AZT, AZT/3TC, AZT/ddI, and d4T/3TC) were significantly (p < 0.05) depleted in mtDNA compared with the unexposed group.