Fig. 5.

Guanylyl cyclase (GC, GUCY) activity at baseline (A), after nitric oxide (NO) stimulation (B), and NO responsiveness (NO-stimulated GC activity normalized to baseline GC activity in the same sample; C), were compared across arteries and between seals and sheep with two-way ANOVAs. GC β-subunit protein abundance is included for representative samples as an inset (70-kDa band; reordered lanes taken from a single, otherwise unmanipulated gel). Based on pairwise post hoc comparisons, GC activity was higher in sheep than in the same tissues of seals with the exception of baseline GC activity in renal arteries, which did not differ between species. NO responsiveness is lower in seal renal artery vs. sheep and in sheep thoracic aorta vs. seal. Sheep: n = 8 all arteries; seal: carotid n = 10, renal and thoracic n = 12). Error bars are means ± SD. Asterisks denote significant Sidak post hoc differences between species (*P < 0.05, **P < 0.01, ****P < 0.0001).