Cardiac mass adaptation in response to pregnancy of WT, myrAkt, and caGSK3β mice. A: in WT, the percent increases in left ventricular mass (LV) normalized to tibial length (LV/TL) were 8.3% and 18.2% in MP (n = 12) and LP (n = 18), respectively, compared with NP (n = 13). In myrAkt mice, LV/TL was increased 10.4% and 15.2% in MP (n = 8) and LP (n = 8), respectively, compared with NP (n = 8). In caGSK3β mice, LV/TL was increased 5.4% and 7.4% in MP (n = 9) and LP (n = 9), respectively, compared with NP (n = 17). B: %fractional shortening (%FS) and %ejection fraction (%EF) measured by echocardiography were significantly decreased in LP (n = 9 for NP and n = 8 for LP) in WT mice. C: %FS and %EF were maintained in LP in myrAkt mice (n = 11/group). D: %FS and %EF were significantly decreased in LP in caGSK3β mice (n = 5/group). Values are means ± SE. For abbreviations, see Glossary. *P < 0.05, significantly different from NP; †P < 0.05, significantly different from MP; ‡P < 0.05, significantly different from WT.