Isatin (Indole-2, 3-dione) inhibits natriuretic peptide-induced hyperthermia in rats.

The effects of an endogenous indole, isatin (indole-2, 3-dione), on the hyperthermia induced by atrial natriuretic peptide (ANP-28), brain natriuretic peptide (BNP-32), and C-type natriuretic peptide (CNP-22) were investigated in rats. Intracerebroventricular administration of each peptide in a dose of 1 microg caused elevations in colon temperature 30 and 60 min after injection. An intraperitoneal (i.p.) injection of isatin (50 mg/kg) abolished the natriuretic peptide-induced hyperthermia. These data reinforce the possible involvement of natriuretic peptides in thermoregulatory processes in the central nervous system, and suggest that isatin might counteract their hyperthermic effect in vivo.