INSULIN AND OR DEXAMETHASONE REGULATION OF LACTATE PRODUCTION AND ITSRELATIONSHIP TO GLUCOSE-UTILIZATION BY OVINE AND BOVINE ADIPOSE-TISSUE EXPLANTS INCUBATED FOR 7 DAYS/

This study investigated the hormonal regulation of lactate production and the lactate production/glucose utilization ratio in sheep and cow adipose tissue (AT) explants. The effects of insulin (2 mU/mL) and/or dexamethasone (DEX, 100 nM) were measured in perirenal AT of adult non -lactating non-pregnant cows (n = 5) or ewes (it = 5) given a restrict ed diet followed by overfeeding. The AT explants were incubated for 7 days. Under basal conditions, the lactate production was two times gre ater in sheep than in cow AT. Insulin increased lactate production in the two species, whereas DEX decreased it. DEX, in the presence of ins ulin, increased lactate production from day 3 to day 7. The lactate pr oduction/glucose utilization ratio was about two times greater in shee p than in cow AT. The presence of insulin increased, and that of DEX d ecreased this ratio in sheep AT, whereas it was not changed in cow AT. DEX, in the presence of insulin, increased this ratio in the two spec ies after 4 or 5 days.