Distribution of injected [U-
14C] galactose in adult, pregnant, newborn and infant mice (ICR strain) and
14C incorporation into the acid-soluble and -insoluble substances of organs were examined by whole-body autoradiography. Autoradiography of whole-body cryosections was performed before and after 6% perchloric acid treatment (untreated and treated autoradiographs).
In the adult mice, [U-
14C] galactose in the peritoneal cavity was completely absorbed into tissues and organs within one hr. Radioactivity peak of blood was attained 5 min after injection. Radioactivities at this time were high in liver and kidney, and relatively high in large and small intestine, myocardium and retina. In the first hr, marked changes of organ radioactivities were seen; Marked decreases in kidney, liver, myocardium, blood, large and small intestine, while increases in salivary glands, Harderian gland and pancreas. However, radioactivity peak in brain was seen at 30min. Incorporation rate of radioactivity into acid-insoluble substances of organs increased at this time: Rates of increase were high for mucous salivary glands, Harderian gland, myocardium and kidney, but relatively low for liver and serous salivary glands and a nearly constant incorporation rate was observed for the brain.
Liver and spleen had a heterogeneous distribution of radioactivity: High radioactivities in liver were around central veins at 5min, and such spots were diffusely distributed in the lobules at 15min, while high radioactivities in spleen were in the red pulps.
In pregnant mice, fetus showed a different distribution pattern of radio-activity from the maternal body with high radioactivities being noted in the myocardium and cartilage. In the placenta, the incorporation rate of radio-activity into its acid-insoluble substances was higher in the fetal portion. During postnatal growth, distribution of radioactivities in kidney, small and large intestine exhibited higher rates, and activities of brain showed an acute increase from 3 weeks.
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