Fig. 1

Electron micrographs of the posterior pituitary glands of wild-type (a) and CD38 knockout (b) mice. Vesicles are nerve endings close to the vascular space (V). Most of the dense core vesicles are oxytocinergic, as determined by immunoelectron microscopic examination. The nerve endings of CD38 knockout mice contain more vesicles than those of wild-type mice, indicating that vesicles are released in the wild-type mice and not secreted in CD38 knockout mice. Bar 500 nm (modified from Fig. 3 of Ref. [21])