The Distribution of ³⁵S from ³⁵S-cysteine in Pregnant mice and Neonates -A Whole-body Autoradiographic Study-

Abstract

In the previous work, we reported the distribution of ³⁵S-taurine in rat neonates and adults using whole-body autoradiography. In the present work, the distribution of ³⁵S-cysteine,precursor of the taurine, in the mouse embryos (approximately 17 days of gestation), neonates ( 1-day-old) and dam was investigated by whole-body autoradiography and compared with that of ³⁵S-taurine, and [1-¹⁴C] cysteine (unpublished data). ³⁵S-cysteine was injected i.v. for the pregnant mice and i.p. for the neonates. Survival intervals were 30 min, 3 and 6 hours. In the dam, ³⁵S from ³⁵S-cysteine was highly incorporated into the pancreas, nasal and intestinal mucus membrane, Harder’s gland, bone marrow, hypophysis and mammary gland, while in the case of the embryo and neonate, it was highly accumulated in bone marrow, skin and hypophysis. When the data were compared with that of ³⁵S-taurine and [1-¹⁴C] cysteine, it was assumed that most of the ³⁵S in the pancreas, nasal and intestinal mucus membrane and Harder’s gland may present in the form of cysteine. On the other hand, in the maternal brain, ³⁵S from ³⁵S-cysteine was significantly incorporated into the pyramidal cell layer of the hippocampus and may present as taurine form. In the developing brain, radioactive sulfur from ³⁵S-cysteine was mainly found in the differentiating neurons of the cortical plate including primordial hippocampal cell layer and of the cerebellar cortical plate, and may be incorporated as cysteine form.