Pituitary halves from normal or thyroidectomized rats were incubated in media containing glucose-l- or glucose-6-14C and the 14C02 produced in 45 min was measured. Synthetic thyrotropin-releasing hormone (TRH) stimulated oxidation of glucose-6-14C to 14C02 but not C-1 labeled glucose. The effect was most consistent and prominent in pituitaries from thyroidectomized rats and was blocked by the addition of thyroxine to the medium. TRH exerted no comparable stimulatory action on liver, brain, kidney, or muscle under comparable conditions. © 1970.