Peripheral Circulatory and Metabolic Consequences of Thyrotoxicosis: I. Blood flow and oxygen consumption of resting and working skeletal muscle in experimental thyrotoxicosis in the dog

Abstract

Frey, H. M. M. Peripheral Circulatory and Metabolic Consequences of Thyrotoxicosis I: Blood flow and oxygen consumption of resting and working skeletal muscle in experimental thyrotoxicosis in the dog. Scand. J. din. Lab. Invest. 19 4-14, 1967. Blood flow and oxygen consumption of the gracilis muscle have been measured in the anesthetized, thyrotoxic dog. The thyrotoxicosis was accompanied by an increase in the oxygen consumption of resting muscle. The relative increase was greater than for the body as a whole. The elevated oxygen consumption of thyrotoxic muscle was accompanied by a proportional increase in muscle blood flow, arteriovenous oxygen difference remaining unchanged. The increase in blood flow through the resting gracilis muscle was proportional to the increase in cardiac output. Oxygen consumption during isometric contractions in response to electrical stimulation of the motor nerve was studied at various stimulation frequencies. An increase in the number of contractions per second caused a greater increase in oxygen consumption in thyrotoxic muscle than in normal. The blood flow response to a similar oxygen expenditure in working muscle, however, was equal in normal and thyrotoxic animals. No difference was noted with regard to caliber and tortuosity of the capillaries in normal and thyrotoxic muscle.