(A and B) The TGF response in vivo in db/+ NOS1flox/flox, db/db NOS1flox/flox, db/+ MD-NOS1KO and db/db MD-NOS1KO mice. n=17 tubules/5 mice per group; *P<0.01 vs db/+; #P<0.01 vs NOS1flox/flox. (C and D) The TGF response in vitro in db/+ NOS1flox/flox, db/db NOS1flox/flox, db/+ MD-NOS1KO and db/db MD-NOS1KO mice. n=14 nephrons/group; *P<0.05 vs db/+; #P<0.01 vs NOS1flox/flox. (E) The GFR in db/+ NOS1flox/flox, db/db NOS1flox/flox, db/+ MD-NOS1KO and db/db MD-NOS1KO mice. n=10; *P<0.01 vs db/+; #P<0.01 vs NOS1flox/flox. Statistical difference in (A and C) was calculated by t-test. Statistical difference in (B and D) was calculated by two-way ANOVA followed by Sidak multiple comparisons test. Statistical difference in (E) was calculated by two-way repeated measures ANOVA followed by Sidak multiple comparisons test.