EFFECTS OF MUSCULAR EXERCISE ON ERYTHROCYTE ADENOSINE TRIPHOSPHATE CONCENTRATION IN PATIENTS WITH INSULIN-DEPENDENT DIABETES MELLITUS ° MARIA DONATELLI, SALVATORE VERGA, CATERINA TERRIZZI, VINCENZA Russo, MARIA LUISA BUCALO, ANTONINA SCARPINATO, GIOVANNI CERASOLA Istituto di Clinica Medica Generale e Terapia Medica I, Cattedra di Clinica di Base, Universitd degli Studi di Palermo Glucose utilization by the glycolytic pathway provides the main source of energy, in the form of adenosine triphosphate (ATP), into the cell. On the other hand, a depressed glycolytic activity involves a diminished supply of energy in the cell that will be limited in its metabolic function. Insulin-dependent diabetes mellitus (IDDM) represents a metabolic disorder in which intracellular glycolytic pathway is inhibited by insulin deficiency, with the subsequent decreased availability of energetic substrates such as ATP'°. The purpose of the present study was to determine the changes of eryth- rocyte ATP in response to an intensive energetic demand (muscular exercise) in patients with insulin-dependent diabetes mellitus by measuring erythrocyte ATP concentration. Blood glucose, free fatty acids (FFA) and lactate changes in response to exercise were also investigated. MATERIALS AND METHODS Ten patients (7 males and 3 females) with IDDM and 10 healthy control subjects with similar distribution as regards sex, age and body weight, were studied. None was or had ever been 7t top athlete. The diabetic patients were all hos- pitalized; none exceeded by more than 15% the ideal body weight according Key-words: Erythrocyte adenosine triiOhosphate; Free fatty acids; Insulin-dependent diabetes mellitus; Lactate; Muscular exercise. • This work was supported by a grant from Ministero della Pubblica Istruzione (60%). Accepted for publication on September 10, 1987. La Ricerca Clin. Lab. 17, 343, 1987. 343