Fig. 7.

Comparison of AQP2 abundances in inner medullas of Sprague-Dawley rats, homozygous Brattleboro rats (−/−) and heterozygous Brattleboro rats (+/−). Here, −/− means that both AVP-neurophysin gene alleles are inactivated, producing a lack of circulating AVP, and −/+ means that 1 AVP-neurophysin allele is intact, allowing normal or near normal levels of circulating AVP. As can be seen, AQP2 abundances are similar in vehicle-treated Sprague-Dawley, AVP-treated −/− Brattleboro, and vehicle-treated −/+ Brattleboro rats. In contrast, the AQP2 inner medullary abundance is markedly suppressed in vehicle-treated −/− Brattleboro rats and tolvaptan-treated Sprague-Dawley rats. Densitometry values (bottom) are normalized to the vehicle-treated −/+ Brattleboro rats.