Hyperthyroid-like metabolic changes induced by chronic administration of compound BW 48/80

The present study examines the metabolic changes caused by chronic mast cell degranulation in rats. Three groups of 5 adult rats each were used: 1) rats treated with increasing doses of BW 48/80 (2 to 6 mg kg-1 day-1, ip, for 4 days); 2) a control group receiving daily saline injections, and 3) rats treated with disodium chromoglycate (DCG) (40 mg kg-1 day-1,ip, for 4 days). The third group was included as a control since DCG blocks mast cell degranulation. Saline- and DCG-treated rats showed little differences except for an increase in spleen wet weight and liver glycogen content in the latter. Chronic treatment with compound BW 48/80 resulted in statistically significant changes such as body weight loss, reduction in thymus and spleen wet weights, decrease in spleen protein content, liver glycogen and blood insulin concentrations, increase in plasma free fatty acids concentration and adrenal wet weight compared to control rats. These metabolic changes are similar to those reported for hyperthyroidism and support previous findings on the possible role of mast cells in the control of thyroid function.