A,B, Same tamoxifen protocol as in Figure 4. Reduction in a disintegrin and metalloprotease (ADAM) 10 and 17 prior to collaterogenesis increases (A) and decreases (B) collateral formation. C, Inhibition of γ-secretase with N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT) enhances collaterogenesis. Constitutive reduction of EC Adam10 (D) or Adam17 (E), beginning at conception, alters collateral number but not diameter (F) in adults.