Circulating levels of growth hormone (GH) in "WistarFurth rats bearing the MtT-\V15 tumor are twenty to thirty times higher than normal. The effect of constantly elevated levels of GH on the pancreatic islets was studied. Tumor-bearing rats (TR) and normal controls (C) were pair-fed for seven weeks. In TR, fasting serum levels of GH and insulin were 599 ± 157 ng./ml. and.142 ± 43 /iU./ml., respectively, and only 18.2 ± 1.9 ng./ml. and 26.9 ± 7.9 /iU./ml., respectively, in the controls. The islets of TR were enlarged with an islet/acinar ratio of 3.38 per cent (C: 0.82 per cent). The extracted pancreatic insulin was 9.84 ± 0.9 mU./mg. (C: 5.36 ± 0.4 mU./mg.). Incubated slices or isolated islets of TR pancreas released greater amounts of insulin when submitted to glucose stimulation. Incorporation of labeled leucine into insulin was increased also in TR. An exaggerated insulin response to a glucose load was found in vivo (peak value at 30 min., TR: 183 dt 42.5 fiU./ml; C: 71 ± 17.9 /*U/ml.). None of the TR became diabetic, however, and two to six weeks after removal of the tumors serum GH levels had returned to normal (17.2 /ig./ml.) as had insulin levels both fasting (19.0 /iU/ml.) and following a glucose load (56.4 fiU./mg.). Insulin output by incubated pancreas decreased 50 per cent (26 fiU./mg.). The islet/acinar ratio returned to normal but the insulin content remained high. These re g "ltft mAi.. cate that in animals exposed to hjyh levels of endogenous GH there is an increased responsiveness of the islets to glu-UTABETES J/:bol-OV, lNovember, !Vo8.

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Reproducible immediate-type respiratory responses were evoked in conscious monkeys, sensitive to inhaled Ascaris suum, for periods up to 18 months. These responses were characterized by decreases in tidal volume and increases in breathing rate that persisted for about 40 min. Maximum changes were seen 3–5 min after exposure to the aerosolized antigen and were often accompanied by coughing and increased movement of the animals within the plethysmograph used for monitoring their ventilatory changes. Significant inhibition of the Ascaris-induced respiratory changes were seen in animals treated with either isoproterenol or cromolyn sodium. However, the latter agent was not effective in reversing histamine-induced ventilatory changes. The conscious monkey appears to be a suitable animal for evaluating potential antiallergic drugs.

Hypersomatotropism was induced in Wistar/Furth fernale rats by inoculation of MtT-W15 tumor. Parametrial fat was removed from pair-fed animals at different periods after the inocu1ati~n of the tumor. Isolated fat cells were incubated with U-' C-glucose, and the conversion of 14 C into C02 and lipids was measured. The changes in the metabolism of glucose in adipose tissue developed in three stages. In the very early stage of hypersomatotropism (serum growth hormone 7-9 ng/ml) there was an increased glucose utilization both in the absence and presem:e of insulin. One to two weeks later, when serum growth hormone had risen to c1early hypersornatotropic levels (36-116 ng/ml) there was a decreased baseline glucose utilization, which could still be correeted by the addition of insulin. When the animals had had the growth hormone producing tumor for several weeks, depot fats were depleted, and the conversion of glucose to C02 and lipids was decreased both in the absence and presence of insulin.

No abstract