[The thick ascending limb of the loop of Henle: a key segment in the renal regulation of acid-base status?].

The thick ascending limb (TAL) of rat kidney has been shown to reabsorb bicarbonate and NH4+. Therefore, in vivo and in vitro studies have demonstrated that bicarbonate absorption by the medullary TAL (mTAL) is influenced by peptide hormones (AVP, PTH), prostaglandin, osmolality and chronic metabolic acidosis. AVP, whose major effect is water balance regulation, also modulates acid-base handling in the mTAL, and then contribute to the regulation of renal acid excretion. These data suggest that the TAL could play an important role in the physiology and pathology of acid-base status.