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The response of hepatic lipase and serum lipoproteins to acute hyperinsulinaemia in type 2 diabetes
Author(s) -
BAYNES C.,
HENDERSON A. D.,
RICHMOND W.,
JOHNSTON D. G.,
ELKELES R. S.
Publication year - 1992
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1992.tb01472.x
Subject(s) - medicine , endocrinology , hepatic lipase , hyperinsulinemia , insulin , lipase , type 2 diabetes , diabetes mellitus , postprandial , lipolysis , chemistry , insulin resistance , cholesterol , triglyceride , enzyme , adipose tissue , biochemistry
. Hepatic lipase has a putative role in the catabolism of HDL particles and, while its activity is dependent upon insulin in the rat, no such insulin responsiveness has been demonstrated in man. We studied 21 patients with type 2 diabetes to examine whether hepatic lipase activity was influenced by hyperinsulinaemia during a 2–4 h isoglycaemic clamp study. Acute changes in lipids, lipoproteins and apoli‐poproteins were also documented in pre‐ and post‐clamp serum. Hepatic lipase activity during hyperinsulinaemia was compared with activity measured after an equivalent period without insulin. For comparison, nine non‐diabetic subjects (matched for age and body mass index) underwent similar clamp studies. In the control experiment without insulin, hepatic lipase activity did not change significantly (mean 9.7 {range 2.3–22.3} in the morning and 9.9 {3.0–22.5} mmol h ‐1 l ‐1 in the afternoon, NS). In contrast, after the hyperinsulinaemic clamp, hepatic lipase activity fell significantly in diabetic subjects from 12.8 {4.4–30.6} to 10.4 {3.3–31.3} mmol h ‐1 l ‐1 , P <0.0002 along with serum triglycerides and total and LDL cholesterol. The change in hepatic lipase activity was positively related to the fasting apoprotein B concentration (Spearman r = 0.54, P = 0.016). In the normal subjects, a similar decline in hepatic lipase activity was observed during hyperinsulinaemia (from 15.1 {9.8–32.7} to 12.6 {6.3–28.3} mmol h ‐1 l ‐1 , P <0.01) along with decreases in total, HDL and LDL cholesterol, triglycerides and apoproteins A 1 and B. The change in hepatic lipase activity was positively related to fasting apoprotein B and total cholesterol concentration (both r = 0.72, P = 0.042) and both the fasting LDL cholesterol (r = 0.82, P =0.021) and the change in LDL cholesterol during the clamp study (r = 0.81, P = 0.022). Thus, acute physiological hyperinsulinaemia in normal and type 2 diabetic man causes a decrease in hepatic lipase activity. This may reflect a direct effect of insulin or, alternatively, it may be secondary to insulin‐mediated alterations in lipopro‐tein metabolism.