Figure 1.
Relative (normalized to baseline) cardiac [ADP], [Pi], and [CrP]/[ATP] versus cardiac oxygen consumption rate (MVO2) from Katz et al. [9].
(A) [ADP], (B) [Pi], (C) [CrP]/[ATP]. Data were obtained from 31P-MRS of the canine myocardium, with MVO2 varied by pacing or infusion of epinephrine or phenylephrine. Data are adapted from Figures 2, 4, and 6 of Katz et al. [9].
Figure 2.
Steady-state phosphate metabolites in the canine heart measured by 31P-MRS.
(A) CrP/ATP is plotted versus cardiac oxygen consumption rate (MVO2). (B) ΔPi/CrP is plotted as a function of MVO2. Solid lines indicate model predictions from [31]; data are adapted from: ○, Zhang et al. [14]; ◃, Zhang et al. [15]; ⋄, Gong et al. [16]; ▵, Ochiai et al. [17]; ▿, Gong et al. [18]; □, Bache et al. [19]. This figure is adapted from Wu et al. [31], with permission. Shaded data points indicate situation when Pi is below limit of detection.
Figure 3.
Facilitated diffusion of ATP hydrolysis potential by the creatine kinase system.
Phosphocreatine (CrP) is synthesized from ATP near sites of ATP synthesis and diffuses to sites of ATP hydrolysis, where ATP is synthesized from CrP.