Insulin uptake and effect on glucose utilization by ovine and bovine adipose tissue cultured over 7 days
Annales de Zootechnie
292 mg/10 9 cells, respectively). Our results showed that NEFA is the best plasma predictor for TG liver infiltration in weeks 1 (r= 0.68), 2 (r= 0.42) and 4 (r= 0.57). Furthermore, plasma LDL, apo B and A-I are other potential predictors with the accuracy of prediction dependent on the time post-partum. Insulin uptake and effect on glucose utilization by ovine and bovine adipose tissue cultured over 7 days. The effect of insulin (2 mU/ml) on glucose utilization was studied on adipose tissue
... n adipose tissue (AT) explants from non-lactating non-pregnant cows (n = 5) and ewes (n = 5) fed a restricted diet (20-22% of energy maintenance requirement, EMR) for 8-10 d and then overfed (188 or 228% of EMR, for cows or ewes) during 21 (cows) or 10 0 (ewes) d until slaughter, to induce a rebound in lipogenic activities. The body condition (scale 0-5) of the cows and ewes averaged 2.5 ± 0.6 and 3.0 + 0.3, and the mean adipocyte diameter 122 ± 3 and 111 ± 9 9 pm, respectively. Samples of perirenal AT were cut into 10-15 5 mg pieces, and cultured over 7 d in sterile conditions in medium 199 supplemented with acetate (7.0 mM). The culture medium was changed daily. Glucose concentration was measured using the glucose dehydrogenase method. The loss of insulin from the cultured medium in the 2 species ranged from 60 (1st d of culture) to approximately 35% (d 2 to d 7) of the initial amount. In basal conditions, the glucose utilization was similar (33-24 and 16 gmol/24 h/10 6 adipocytes on d 1-2, 3-4 and 5-6-7, respectively) in the 2 species. However, the glucose utilization by bovine AT was higher (+18%) during the 2nd than during the 1st d, in contrast to ovine AT where this utilization decreased (-13%) during this period. In the 2 species, the glucose utilization then progressively decreased until d 7. The addition of insulin increased (P < 0.001 ) glucose utilization in the 2 species. However, the effect of insulin was different according to the species and the day of culture (interaction species x insulin x day, P < 0.03). The effect of insulin on d 1 was greater in bovine (+67%) than in ovine (+20%) AT, whereas on d 3-4 and d 5-6-7 this effect was greater in ovine (+92 and 132%) than in bovine (+64 and 50%) AT. This study indicates that ruminant AT explants remain metabolically active for at least 7 d when maintained in a suitable medium, with interactions between insulin and animal species that affect glucose utilization.