Telomerase Activity after Partial Hepatectomy

Takuo Inui, Kazuo Hatsuse, Tsukasa Aihara, Yasushi Okusa, Noritsugu Kuranaga, Nobuaki Kawarabayashi, Hironori Tsujimoto, Toshimichi Takigawa, Nariyoshi Shinomiya^* and Hidetaka Mochizuki

First Department of Surgery and Department of Microbiology^*, National Defense Medical College

Telomerase activity is undetectable in adult human tissues, but in proliferating hepatocytes it can be present during liver regeneration. In this study we investigated the activation of telomerase in the rat hepatic remnant, the ratio of the cell cycle (G₀/G₁ phase, S phase, G₂/M phase), the regeneration rate and the average regeneration rate per hour of the hepatic remnant at 12, 24, 36, 48, 72 hrs, 1 wk, and 4 wks after 70% partial hepatectomy in rats. Telomerase activity was assayed by the telomeric repeat amplification protocol which we modified (modified TRAP) and quantitated by using an internal standard. Telomerase activity was strongly detected at 12 and 24 hrs (p<0.001), and then decreased gradually to the normal level at 1 wk after hepatectomy, whereas the peak of the proportion of the S phase was at 24 and 36 hrs after the operation. The average regeneration rate per hour of the hepatic remnant correlated significantly with the telomerase activity (r=0.858, p<0.001). In conclusion, these findings may suggest that hepatectomy mediate the activation of telomerase and indicate that the activity is strongly increased before DNA synthesis.

Key words
telomerase activity, liver regeneration, partial hepatectomy, cell cycle, regeneration rate (per hour)

Reprint requests
Takuo Inui First Department of Surgery, National Defense Medical College 3-2 Namiki, Tokorozawa, 359-8513 JAPAN

Accepted
September 22, 1999

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