Decreased levels of an inhibitor of prostaglandin E 9-ketoreductase activity in chick dystrophic breast muscle

Abstract

A WIDE range of membrane anomalies is one of the characteristics of dystrophic muscle^1,2. Since prostaglandins (PGs) are known to interact with such membrane constituents as adenyl and guanyl cyclase; Mg²⁺-dependent, Na⁺/K⁺-activated ATPase; Mg²⁺-dependent, Ca²⁺-activated ATPase; adenylate kinase; and phosphodiesterase³, it seemed desirable to search for a possible relationship between PGs and the dystrophic condition. The activities of two potentially regulatory PG-metabolising enzymes were measured. NAD⁺-dependent 15-hydroxyprostaglandin dehydrogenase activities⁴ in the breast muscles of 10-d post-hatching chicks with hereditary muscular dystrophy (New Hampshire strain) and the breast muscles of 10-d post-hatching normal (white leghorn) chicks were the same as those in the leg muscles of these animals. PGE 9-ketoreductase activity^5,6 in the dystrophic breast muscle was considerably more active than its control (normal) breast muscle. Subsequently, it was found that the normal breast muscle contains a much higher level of an inhibitor of PGE 9-ketoreductase activity than dystrophic breast muscle.