Figure 4.

Localization of the kallikrein-kinin system along the nephron. Kallikrein is produced in the convoluted connecting tubule, kininogens in the cortical portion of the collecting duct and kinins along the collecting duct. Filtered blood kinins are mainly destroyed by kininases located along the proximal tubule. Activation of kinin receptors in the nephron leads to production of prostaglandin E2 (PGE2) along the medullary portion of the collecting duct. Drawing of the nephron was kindly provided by Dr. William H. Beierwaltes.