Mechanical stresses appear to play a key role in the progression of glomerular diseases that are characterized by increased transcapillary hydraulic pressure. Glomerular mesangial cells proliferate and produce extracellular matrix proteins in vivo in such diseases. Mesangial cell responses to pulsatile mechanical stimuli have been studied extensively in vitro during the past few years. Mechanical signals are sensed at the cell membrane and propagated through the cytoplasm, and result in the activation of transcription factors that elicit production of prosclerotic cytokines and matrix proteins, and cell proliferation. Endothelial cells are exposed to shear and pulsatile stress and show some similar responses in other vascular beds.