The manuscript has withdrawn due to plagiarism
Brown adipocytes isolated from brown adipose tissue (BAT) of cold-acclimated
rats do not respond to NA in spite of their marked thermogenic response in vivo.
In contrast, in cold-acclimated Guinea pigs, isolated brown adipocytes show
substantial increase in capacity for a thermogenic response to NA. Chronic stimulation
with a β3-AR agonist increased insulin-sensitivity of BAT in the Guinea
pig. To investigate the responsiveness of glucose transport to insulin, to NA
and to β3-AR agonists we used BAT of Guinea pigs. Results of this study
showed that no β3-adrenergic agonist used, such as CL 316,243, BRL 37344,
was able to stimulate oxygen uptake in BAT cells from cold-acclimated or new
born Guinea pigs. However, noradrenaline (NA), adrenaline (A) and isoproterenol
(ISO) had a marked thermogenic effect on these cells. In contrast, in a comparative
study in warm-acclimated rat BAT cells, CL 316,243 was even more potent than
NA in stimulating oxygen uptake. We concluded that Guinea pigs lack β3-ARs
in their BAT. These results were interesting and noteworthy, suggesting that
Guinea pigs can be a natural model for β3-ARs knockout.
