Light and electron microscopic radioautographic studies on macromolecular synthesis in digestive organs of aging mice.

For the purpose of analyzing the changes of macromolecular synthesis in aging animals, we have developed methodologies for quantitative light and electron microscopic radioautography. The methodologies were applied to DNA, RNA, protein, glucides and lipids syntheses of digestive organs, especially of the liver and the pancreas of aging strain ddY mice, demonstrating the incorporations of respective precursors, 3H-thymidine, 3H-uridine, 3H-leucine, 3H-glucosamine, 35S-sulfuric acid and 3H-glycerol. Characteristic differences have been observed between the respective macromolecular syntheses in respective aging groups, from prenatal (embryonic day 19) to postnatal newborn period (postnatal day 1), from suckling (postnatal day 3) to weaning (postnatal day 14), juvenile (postnatal 1 month), young adult (postnatal 2 month) and senescent periods (6 and 12 months up to 2 years). These results are extensively analyzed and reviewed.