Induction of intercalated cell changes in rat pups from acid- and alkali-loaded mothers.

We evaluated the effects of acid-base changes in pregnant and lactating dams on intercalated cell morphology and populations in newborn and 2-wk-old rats. Collecting ducts were studied with transmission electron microscopy with intercalated cells identified by the presence of 10-nm studs in the cytoplasmic face of apical membranes (A-type intercalated cells) or basolateral membranes (B-type intercalated cells). In newborn and 2-wk-old pups from dams with metabolic alkalosis, there was a significantly larger percentage of B-type intercalated cells and a smaller percentage of A-type intercalated cells. Acid loading with NH4Cl, however, did not produce an increase in the percentage of A-type intercalated cells, but reduced the percentage of B-type intercalated cells. We conclude that maternal metabolic alkalosis is associated with an increase in the percentage of B-type intercalated cells, suggesting that the initial differentiation of intercalated cells is responsive to maternal acid-base disturbances.