Influences of growth hormone on glucose uptake by avian adipose tissue

The uptake of glucose by chicken adipose tissue was determined in vitro using adipocytes or adipose explants using 14C orthomethyl glucose (OMG). The net uptake of 14C-OMG was enhanced by preparations of bovine and chicken GH and by insulin. Insulin and growth hormone (GH) (chicken or bovine) stimulated the uptake of 14C-OMG occurring in 1 hr by adipose tissue (both adipocytes and explants) from chicks hypophysectomized for 5 days but not from sham-operated birds. Tissue preincubated with GH became refractory to GH stimulation of 14C-OMG uptake. The short-term (2 to 15 min) uptake of 14C-OMG by explants was, however, stimulated by the bovine GH and insulin in tissue from sham-operated but not hypophysectomized chicks. Surprisingly, net decreases in 14C-OMG uptake, in the presence of bovine GH, were observed with adipose tissue (adipocytes and explants) from hypophysectomized birds, when incubated in the presence of epinephrine, and from hypophysectomized birds immediately following surgery.