Many substances have been used after partial hepatectomy in order to determine their effect on the regeneration process. One of them is growth hormone. We divided 50 male Wistar rats aged 170 days and weighing on average 380g into two groups of 25 animals each (experimental and control groups) to determine the effect of this growth hormone. The animals were anesthetized with ethyl ether and submitted to median laparotomy and a 70% hepatectomy, by medium and left lateral lobes resection. The removed lobes were weighed and the abdomen closed. The rats in the experimental group received growth hormone by daily subcutaneus injection of a 0,4 U/Kg dose, in a volume of 0,12 ml. Control animals received an equal volume of distilled water, injected by the same route. Five animals from each groups were then sacrificed after 36, 72, 168, 240 and 336 hours, and the weight of each animal and of the liver was determined. Hepatic regeneration was calculated by the formula of Kwon et al. and mitotic figures observed in 20 histological fields by light microscopy. Percentage weight of the regenerated liver was higher in the animals treated with growth hormone at 168 h (p=0,011), 250 h (p=0,011) and 336 (p<0,0001). In the experimental group, regeneration was complete starting at 168 h, whereas in controls did not reached 100% after 336 h. Mitotic figures were present in the experimental group up to 240 hs, and were present in significantly higher numbers in the experimental group at 36 h (p<0,001) and 72 h (p<0,01). We conclude that growth hormone leads to a more rapid regeneration of the liver after hepatectomy in rats.
Liver; Hepatic regeneration; Growth hormone
