Clinica Chimica Acfu, 193 (1990) 79-84 Elsevier 19 CCA 04846 Altered protein kinase C and protein kinase A activities in erythrocyte membrane, platelets and lymphocytes of Duchenne muscular dystrophy (DMD) patients G. Jagadeesh ‘, Moses Lavanya I, M.P.J.S. Anandaraj ’ and A. Anjaneyulu * ’ Institute of Genetics and Hospital for Genetic Diseases, Osmania University, Begumpet, Hyderabad and 2 Nizam’s Institute zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJI of Medicai Science, Hyderabad (India) (Received 5 January 1990; revision received 6 August 1990; accepted 7 August 1990) Key wordv Duchenne muscular dystrophy; Calcium activated neutral protease; Protein kinase C; Protein kinase A Duchenne muscular dystrophy (DMD) is an X-linked recessive disease, manifest- ing progressive and severe muscle degeneration beginning very early in life and culminating in death by the second decade [l]. Emery and Burt have suggested that alteration in intracellular calcium is one of the early biochemical changes in DMD and could be related to the primary event of pathology 121. An increase in total intracellular calcium observed both in muscle fibre 121 and in platelets [4,5] suggests a cellular defect in calcium metabolism. Mean free calcium was found to be higher in the platelets of DMD patients than in those of control subjects, despite a considerable overlap between the two groups [6]. Recently dystrophin, a newly recognised muscle specific protein has been identified as the DMD gene product, which is deficient in disease condition [7], al~ou~ the pathogenic process, clinical progression and their relation to dystrophin deficiency are not fully elucidated. Dystrophin which is shown to be a plasma membrane bound intracellular cyto- skeletal protein is believed to be involved in the regulation and calcium release from sarcoplasmic reticulum [S]. Distribution of dystrophin showed that its quantitative expression differs from tissue to tissue; taking its levels in skeletal muscle as lOO%, the expression in cultured l~phobl~toid cells was as low as 0.004% 191.It is well documented that non-muscle cells such as erythrocytes [10,11,12], lymphocytes [13,14], platelets [15,16] and fibroblasts [3,12] show many membrane and calcium- dependent changes not necessarily due to dystrophin deficiency [17]. In our study Correspondence to: Dr. H.P.J.S. Anandaraj, Institute of Genetics & Hospital for Genetic Diseases, Osmania University, Begumpet, Hyderabad, India. 0009-8981/90/$03.50 0 1990 Elsevier Science Publishers B.V. (Biomedical Division)