title: [Space-time changes in isocitrate dehydrogenase activity in the rat liver].
abstract: The author describes a quantitative histochemical test of NAD- and NADP-dependent isocitrate dehydrogenase (ic-NAD and ic-NADP) activity changes in relation to the time of day and topographic locality in the hepatic lobule. It was established that activity of the enzymes was characterized by monophase circadian rhythms, with the phase of ic-NAD activity observed in the dark period and ic-NADP activity in the light period of day. Rhythmic fluctuations in ic-NAD activity in different regions of the lobule were more synchronized than those in ic-NADP activity. Spatial changes in the activity of both the enzymes were fairly similar, decreasing from the center to the periphery of the lobule up to the end of the median and peripheral area. The changes in ic-NADP activity were more uniform in nature as compared to those seen in ic-NAD. The most demonstrable differences in the activity of both enzymes among adjacent hepatocytes could not be localized to any particular area in the lobule, moving regularly through its areas during the day. Thus, the functional heterogeneity of hepatocytes should be studied, from the standpoint of the activity of the enzymes, in close relation with time and space changes in their metabolism.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D006651:Histocytochemistry; D007521:Isocitrate Dehydrogenase / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D051381:Rats; D013997:Time Factors
chemical_list: D009243:NAD; D009249:NADP; D007521:Isocitrate Dehydrogenase
vernacular_title: Prostranstvenno-vremennýe izmeneniia aktivnosti izotsitratdegidrogenazy v pecheni krys.