Figure 7.

Acute oestrogen receptor‐dependent regulation of cardiac myofilament function is dependent on ovarian function. A, Oestrogen receptor‐α or ‐β stimulation of intact hearts increased maximum actomyosin MgATPase activity as compared to vehicle‐treated controls. B, EC₅₀ increased in myofilaments from intact hearts following DPN treatment, but was not altered by PPT. C, Hill coefficient was not altered by oestrogen receptor activation in intact hearts. D, Myofilament function in hearts from mice 60 days after VCD treatment did not show any change in maximum activity in response to oestrogen receptor activation. E, EC₅₀ was unaffected by oestrogen receptor activation in 60 day post‐VCD‐treated mouse hearts. F, Hill coefficient was not affected by oestrogen receptor agonists. G, At 120 days after VCD treatment maximum actomyosin MgATPase activity remained unaffected by oestrogen receptor stimulation. H, Oestrogen receptor‐α stimulation with PPT decreased EC₅₀ in myofilaments from hearts 120 days post‐VCD injection. I, Hill coefficient was not impacted by either oestrogen receptor agonist. Note: VCD 60 D, 60 days after VCD injections; VCD 120 D, 120 days after VCD injections. N = 7 per group. P < 0.05 vs control for each group