Fig. 5.

Effects of hypoxia on PKG activity. Using a peptide substrate derived from bovine phosphodiesterase (abbreviated as BPDE in the figure), whole artery PKG activity (line graph, nmol ³²P-labeled BPDE/relative unit PKG) was not significantly affected by hypoxia in either fetal or adult homogenates. Total PKG activity was greater in fetal compared with adult artery tissue homogenates, which reflects the modestly greater total PKG abundance in fetal arteries. When whole artery PKG activity was normalized relative to PKG abundance (Fig. 4), estimates of specific activity (inset, nmol ³²P-labeled BPDE/min/relative unit PKG) did not vary significantly with hypoxia. Error bars indicate means ± SE for n ≥ 5.