Calponin (h1 or basic) is an actin-binding protein that is expressed abundantly in smooth muscle. Our previous study using h1 calponin-null mutant mice demonstrated that h1 calponin inhibits the shortening velocity of smooth muscle contraction without significantly affecting the amplitude of force production. Furthermore, early onset of osteogenesis and increased bone formation have been reported in mutated mice. In the present study, we examined the effect of h1 calponin depletion on the metabolism and behavior of mice and found that the mutated mice showed increased locomotor activity, as well as increased intake of food and water, associated with the decreased number of neurons in the paraventricular nucleus of the hypothalamus (PVN).