Hepatic regeneration and metabolism after partial hepatectomy in diabetic rats: effects of insulin therapy

Abstract

The effect of insulin deficiency on liver regeneration has been assessed in untreated v. insulin-treated streptozotocin (65 mg kg-1) diabetic rats, 12, 24 and 48 h after partial hepatectomy. Dry weight of regenerating liver increased from 12 to 48 h after partial hepatectomy and insulin treatment caused a further minor increase at 24 h. [6-3H]Thymidine uptake in untreated rats peaked at 24 h (12.5 +/- 3.4% of total cells labelled). Insulin therapy produced a delayed 168% rise in uptake at 48 h. Insulin deficiency alone in sham-operated animals caused a 33% decrease in hepatic [ATP], while [ADP] rose by 43% and [AMP] by 86% at 12 h. Partial hepatectomy produced only minor further abnormalities in untreated animals. Insulin therapy increased hepatic [ATP] and decreased [ADP] and [AMP] 12 h after partial hepatectomy, but [ATP] remained decreased (15%) and [ADP] and [AMP] increased (45% and 73% respectively) compared with insulin-treated sham-operated controls. Metabolite changes observed after partial hepatectomy in untreated animals, including a decrease in hepatic [glycogen] and increases in [triglyceride] and the ratios of [lactate]:[pyruvate] and [3-hydroxybutyrate]:[acetoacetate], were partially reversed by insulin treatment. Insulin deficiency thus impairs regeneration after partial hepatectomy and magnifies the decline in hepatic intracellular energy state and the metabolite changes associated with liver regrowth.