环孢菌素 H

The cyclic undecapeptide, cyclosporin H, is a potent inhibitor of formyl-Met-Leu-Phe (FMLP)-induced superoxide anion (O2-) formation in human neutrophils. Cyclosporin H inhibits FMLP binding in HL-60 membranes with a K _i of 0.1 μM. Cyclosporin H inhibits activation by FMLP of high affinity GTPase (the enzymatic activity of alpha-subunits of heterotrimeric regulatory guanine nucleotide-binding proteins) in HL-60 membranes with a K _i of 0.79 μM. Cyclosporin H inhibits the stimulatory effects of FMLP on cytosolic Ca ²⁺ concentration ([Ca ²⁺ ]i), O2- formation, and beta-glucuronidase release with K _i values of 0.08, 0.24, and 0.45 μM, respectively.

Cyclosporin H (5 mg/kg; i.p.; before LPS or HCl challenge) attenuats lung injury induced by LPS or HCl (a lung injurymodel).