| Autor: |
Ekanger, R, Vintermyr, O K, Houge, G, Sand, T E, Scott, J D, Krebs, E G, Eikhom, T S, Christoffersen, T, Øgreid, D, Døskeland, S O |
| Zdroj: |
Journal of Biological Chemistry; March 1989, Vol. 264 Issue: 8 p4374-4382, 9p |
| Abstrakt: |
The levels of the regulatory (RI and RII) and catalytic (C) components of cAMP-dependent protein kinase and of their messages were studied during the first 36 h of liver regeneration after 70% hepatectomy. Both RI α mRNA and RII α mRNA started to increase 4 h after the resection, reaching peak levels after 9 h. RI mRNA decreased abruptly 9–12 h after resection, whereas RII mRNA stayed elevated. C α mRNA was rather constant during the period of study. In accordance with the mRNA data the level of C was constant while RI and RII increased during the prereplicative phase of liver regeneration. RI increased rapidly when its message became elevated. RII, however, increased noticeably only 6–8 h after its mRNA had become elevated. The increased expression of R led to a disproportion between R and C that was most pronounced 14 h after resection, i.e.coinciding with the prereplicative cAMP burst. The increased R/C ratio at that time of regeneration diminished the concentration of active C subunit during the cAMP burst. In that way the otherwise inhibitory effect of high concentrations of active C on the DNA replication may have been decreased. The fractional saturation of RI and RII by endogenous cAMP fluctuated in parallel as a function of liver cAMP levels, although there was a tendency that RI was more highly saturated than RII at high concentrations of cAMP. |
| Databáze: |
Supplemental Index |
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