Sparse Distribution of Hepatocyte Growth Factor‐producing Cells inside Hepatocellular Foci in Rats Treated with Hepatocarcinogens

The distribution of hepatocyte growth factor (HGF)–synthesizing cells in rat liver during development of glutathione S–transfcrasc P form (GST–P)–positive nodules after diethylnitrosamine initiation followed hy promotion with 2–acetylaminofluorene plus partial hepatectomy (PH) was investigated using in situ hybridization, HGF–produclng cells were iioii–parenchymal in nature, and were suspected to be mainly of Kupffer type. They were mostly located outside GST–P–positive lesions, in the surrounding parenchyma. In the oval cell proliferation phase 1 week after PH, they increased and they were mainly localized around the portal triads. It is concluded that HGF is directly involved in an endogenous paracrine growth pathway controlling proliferation in oval cells and in normal, hut not GST–P–positive, hepatocytes.