Insulin-Mediated Glucose Metabolism Is Related to Liver Structure and Microsomal Function

Abstract

The role of the liver in glucose metabolism was investigated in 24 consecutive patients undergoing diagnostic liver biopsy by comparing hepatic morphometry and microsomal enzyme activity in vivo (antipyrine) with fasting blood glucose (BG) and immunoreactive insulin (IRI) levels and with the metabolic clearance rate of insulin and the insulin sensitivity index. The patients had elevated BG and IRI levels and reduced insulin-mediated glucose metabolism, insulin sensitivity index, and microsomal enzyme activity as compared with controls. The insulin metabolic clearance rate did not diverge among the groups. Patients with fatty liver had a high BG associated with a reduced glucose disposal rate, whereas fasting IRI did not diverge when compared with other liver patients. Glucose disposal rate was related to the amount of unaltered liver (r² = 0.640; p < 0.001) and antipyrine metabolism (r = 0.631; p < 0.01) and inversely related to the amount of fat (r² = 0.585; p < 0.01). The findings demonstrate that insulin-mediated glucose metabolism is related to liver structure and microsomal function. Accumulation of fat in the liver seems to be a major factor associated with reduced insulin sensitivity and glucose tolerance.

Key Words:

• Antipyrine
• glucose disposal rate
• liver histology
• microsomal function
• morphometry