A Turing degree is d.c.e. if it contains a set that is the difference of two c.e. sets. A d.c.e. degree d is isolated by a c.e. degree a < d if all c.e. degrees that are below d are also below a ; d is isolated from above by a c.e. degree a > d if all c.e. degrees that are above d are also above a . In this paper, we study the inductive strength of both isolated and upper isolated d.c.e. degrees from the point of view of reverse recursion theory. We show that (1) P − + B Σ 1 + Exp ⊢ I Σ 1 ↔ There is an isolated proper d.c.e. degree below 0 ′ ; (2) P − + B Σ 1 + Exp ⊢ I Σ 1 ↔ There is an upper isolated proper d.c.e. degree below 0 ′ .