Performing 129Xe morphometry at multiple pressures allows for direct mapping of microstructural changes and micromechanical properties of the lung (eg. pseudo-compliance) in both health and disease. In the present study, the effects of posture and gravity on the linear portion of lung pseudo-compliance are investigated using this approach in healthy mechanically-ventilated rats. Spatial gradients in lung pseudo-compliance due to gravity and posture are shown to vary, consistent with the expectations that the lungs are denser dorsally due to the weight above. Scaled regional pseudo-compliance is shown to be in agreement with whole lung compliance measured using 1H MRI.