Densitometric measurements from immunoblots of MLCK, which show a transient increase in the content of MLCK at 3 weeks of age (P<0.05 by ANOVA) in extracts of tracheal smooth muscle from 1wk, 3wk, and adult guinea pigs. Values are mean ± SE of twelve 1wk, eleven 3wk, and twelve adult samples (from Chitano et al. 2004, with permission).