Which statement below does NOT correctly describe paracrine regulation?

A. Paracrine regulatory molecules include cytokines and growth factors.
B. Nitric oxide can function either as a neurotransmitter or a paracrine regulatory molecule.
C. Endothelin and bradykinin are paracrine molecules that control blood vessel constriction and dilation.
D. Paracrine molecules are released into the circulatory system to affect distant tissues.
E. Platelet - derived growth factor and insulin - like growth factor are both paracrine regulatory molecules.