The Action of Various Hormones and Metabolites upon Glucose Production by Isolated Hepatocytes from Lactating and Non-Lactating Ewes

Abstract

Glucose production was measured from hepatocytes isolated from the livers of non-mated, 20- and 50-day lactating ewes (4 animals/group) in the presence and absence of various substrates and hormones. The output of glucose was reduced at peak lactation (20-day) compared to both the unmated (P less than 0.05) and 50-day lactating groups (P less than 0.05). There was no significant difference in glucose production between the unmated and 50-day lactating groups. In the presence of glucagon (1 uM), glucose production was stimulated above control levels (P less than 0.05). However, insulin (1 uM) did not reduce glucose production compared to controls, while the effect of insulin and glucagon combined (1:1 uM) was not significantly higher than control values. Propionate, acetate and butyrate (10 mM) significantly increased glucose output above control values (P less than 0.05), in all three groups of animals. Glucose output was relatively unchanged in the presence of alanine and glutamate (10 mM), while fructose supplementation (10 mM) resulted in a significantly reduced glucose output compared to the controls (P less than 0.05).