Fig. 6. Ontogeny of hepatic G1-cyclin protein content. Densitometry of Western immunoblotting analysis of cyclin D1 from whole-liver homogenates (A), cyclin D1 from nuclear extracts (B), and cyclin E from nuclear extracts (C) is shown with accompanying representative autoradiogram (insets). P.25, 6 h after birth; P.75, 18 h after birth. Results for all of the experiments were replicated three times.