Lipoprotein lipase and glucose-6-phosphate dehydrogenase activities in bovine and ovine adipose tissue incubated for 7 days: effects of insulin and/or dexamethasone.
The in vitro regulation of lipoprotein lipase (LPL) and glucose-6-phosphate dehydrogenase (G6PDH) activity in bovine and ovine adipose tissue was investigated. Adult non-lactating non-pregnant cows (n = 5) or ewes (n = 5) were given limited amounts of feed for 8 or 10 days and then overfed for 10 (ewes) or 21 (cows) days. Perirenal adipose tissue explants were incubated for 2, 4 or 7 days. Regardless of the experimental conditions, the activity of LPL and G6PDH after 2 days of incubation was lower than in fresh tissue. Insulin significantly increased LPL activity in bovine but not in ovine adipose tissue, and it had no effect on G6PDH activity in the two species. Dexamethasone addition to the insulin-supplemented medium significantly increased LPL activity in ovine adipose tissue, whereas it was decreased in bovine adipose tissue on days 4 and 7. Moreover, dexamethasone addition to the insulin-supplemented medium did not change G6PDH activity in the two species on day 2, whereas it was increased in bovine and ovine adipose tissue on days 4 and 7. Therefore, the effects of insulin and/or dexamethasone on LDL and G6PDH differed with ruminant species and incubation time.
Faulconnier
Y
Y
Institut National de la Recherche Agronomique, Theix, Ruminant Undernutrition Laboratory, Saint Genès Champanelle, France.
Guillon
L
L
Chilliard
Y
Y
D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D001835:Body Weight; D002417:Cattle; D003907:Dexamethasone / Q000494:pharmacology*; D004435:Eating; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D007668:Kidney; D007700:Kinetics; D008071:Lipoprotein Lipase / Q000378:metabolism*; D009924:Organ Culture Techniques; D012756:Sheep; D013997:Time Factors
D007328:Insulin; D003907:Dexamethasone; D005954:Glucosephosphate Dehydrogenase; D008071:Lipoprotein Lipase