Observation on incorporation of 3H-taurine in mouse skeletal muscle cells by light and electron microscopic radioautography.

Taurine, one of the sulfur-containing amino acids, exist abundantly in the skeletal muscle tissues. The physiological function and ultrastructural cellular localization of taurine in the skeletal muscle cells are not clear. In this report, two experiments by radioautography were made to elucidate intracellular localization of this amino acid in the skeletal muscle cells. First, muscle tissue pieces obtained from normal and muscular dystrophy mice were cultured in a medium containing 3H-taurine and radioautographed. The number of silver grains appeared on muscle cells increased depending on the duration of the incubation time. Secondly, 3H-taurine was injected intraperitonealy in normal and muscular dystrophy mice. Then muscle specimens were fixed by two fixative procedures, one by a chemical fixation with glutaraldehyde and osmium tetroxide and another by cryo-fixation. Silver grains appeared over muscle cells prepared with both procedures. Silver grains were localized on myofilaments, sarcoplasmic membranes, sarcoplasmic reticulum, mitochondria, endothelial cells of blood capillaries and the cells of perineural sheath, but did not appear on Golgi apparatus, nuclei of muscle cells or adipose cells by any procedures. No difference in localization of silver grains was observed between normal and muscular dystrophy mice.