Studies in Rats of Combined Muscle and Liver Perfusion and of Muscle Extract Indicate That Contractions Release a Muscle Hormone Directly Enhancing Hepatic Glycogenolysis.

Background: Established neuroendocrine signals do not sufficiently account for the exercise-induced increase in glucose production. Using an innovative, yet classical cross-circulation procedure, we studied whether contracting muscle produces a factor that directly stimulates hepatic glycogenolysis. Methods: Isolated rat hindquarters were perfused in series with isolated livers.

Impaired glycogen breakdown and synthesis in phosphoglucomutase 1 deficiency.

Objective: We investigated metabolism and physiological responses to exercise in an 18-year-old woman with multiple congenital abnormalities and exertional muscle fatigue, tightness, and rhabdomyolysis.

Methods: We studied biochemistry in muscle and fibroblasts, performed mutation analysis, assessed physiological responses to forearm and cycle-ergometer exercise combined with stable-isotope techniques and indirect calorimetry, and evaluated the effect of IV glucose infusion and oral sucrose ingestion on the exercise response.

Results: Phosphoglucomutase type 1 (PGM1) activity in muscle and fibroblasts was severely deficient and PGM1 in muscle was undetectable by Western blot.

Gene expression profiling in patients with polymyalgia rheumatica before and after symptom-abolishing glucocorticoid treatment.

Background: The pathophysiology, including the impact of gene expression, of polymyalgia rheumatica (PMR) remains elusive. We profiled the gene expression in muscle tissue in PMR patients before and after glucocorticoid treatment.

Methods: Gene expression was measured using Affymetrix Human Genome U133 Plus 2.

Skeletal muscle metabolism during prolonged exercise in Pompe disease.

Objective: Pompe disease (glycogenosis type II) is caused by lysosomal alpha-glucosidase deficiency, which leads to a block in intra-lysosomal glycogen breakdown. In spite of enzyme replacement therapy, Pompe disease continues to be a progressive metabolic myopathy. Considering the health benefits of exercise, it is important in Pompe disease to acquire more information about muscle substrate use during exercise.

Circadian variations in clinical symptoms and concentrations of inflammatory cytokines, melatonin, and cortisol in polymyalgia rheumatica before and during prednisolone treatment: a controlled, observational, clinical experimental study.

Background: In contrast to rheumatoid arthritis (RA), no systematic investigation of diurnal variation has been carried out in polymyalgia rheumatica (PMR). The aim of the study was to provide the often-requested documentation of the 24-h time course of clinical symptoms in PMR and relate them to concentrations during the day of melatonin, inflammatory cytokines, and cortisol. Furthermore, the effects of 14 days of prednisolone treatment were studied.