[Comparison of the composition of proteoglycans isolated from intact and regenerating rat livers]

Using electrophoresis on acetate-cellulose membranes, the composition of proteoglycans from intact and regenerating rat liver was compared within the first 24 hours after partial hepatectomy. It was found that proteoglycan preparations from intact and regenerating liver contain five fractions corresponding to proteoheparan sulfates I, II and III, proteochondroitin sulfate B and proteochondroitin sulfate AC. Two-phase reciprocal changes in the content of proteoheparan sulfates I and II took place during regeneration. On the 6th and 15th hours after partial hepatectomy, the proteoheparan sulfate I content was maximal, while that of proteoheparan sulfate II is minimal; the maximum content of proteoheparan sulfate II and the minimum content of proteoheparan sulfate I were observed on the 12th hour. Since the maxima of reciprocal changes in the proteoheparan sulfates I and II levels coincide with the activation of liver DNA transcription preceding DNA replication as well as with the relatively synchroneous outburst of mitotic activity, it was assumed that proteoheparan sulfates play a regulatory role in cell proliferation.