Temperature dependence of ADH-induced water flow and intramembranous particle aggregates in toad bladder.

Antidiuretic hormone (ADH)-induced luminal intramembranous particle aggregates and hormonally stimulated water flow in toad urinary bladder are reduced simultaneously with a reduction in temperature. When water movement is factored by the aggregation response, the apparent activation energy for this process decreases from 12.1 +/- 1.6 to 3.0 +/- 2.3 kilocalories per mole. The data are consistent with the view that the particle aggregates contain sites for transmembrane water movement and that these sites behave as pores.