DECREASE IN THE EXPRESSION OF HEPATIC LIPASE ACTIVITY FOLLOWING PARTIAL-HEPATECTOMY

Variations in hepatic lipase (HL) activity were studied for the first time in liver, plasma and adrenal glands of partially hepatectomized ( 70%), sham-operated and intact rats. Activity profiles performed durin g 7 days in liver, plasma and adrenal glands of sham-operated rats wer e similar to those obtained in intact animals. However, HL activity in intact animals appeared to be slightly higher during the first 24 hou rs. Following surgery, hepatectomized animals showed a reduction of ab out 300 U in liver HL activity which persisted for 7 days, Plasma HL a ctivity of hepatectomized rats was undetectable at 6 hours post-surger y but it increased afterwards. A high correlation between liver and ad renal gland HL activity was found in hepatectomized but not in sham-op erated animals. HL mRNA levels in hepatectomized rats showed a 40% dec rease during the first 24 hours after surgery, hut they returned to th e normal range later. On the other hand, HL mRNA values increased in s ham-operated rats but no increase in HL activity was detected in these animals. To conclude, our results show that HL activity decreases dra matically during hepatic regeneration due to a concomitant decrement i n the expression of the gene that encodes the enzyme and to other unde termined factors.