EFFECTS OF HYPERGLYCEMIA AND HYPOGLYCEMIA ON BLOOD GROWTH-HORMONE LEVEL IN FREE-FEEDING RATS WITH ANTEROLATERAL DEAFFERENTATION OF THE MEDIAL BASAL HYPOTHALAMUS

In rats with anterolateral deafferentation of the medial basal hypotha lamus, the growth hormone (GH) level in the blood showed irregular and small fluctuations instead of the usual high bursts and low trough le vel, and the baseline GH level was higher than that in sham-operated r ats. Continuous infusion of a glucose solution to operated rats increa sed the baseline level, GH pulse and pulse amplitude. I.v. bolus injec tion of the glucose solution resulted in a significant but transient i ncrease in GH level. Insulin-induced hypoglycemia decreased the blood GH level in operated rats more effectively than in sham-operated ones and that was prevented by simultaneous infusion of glucose. Since SS i nfluence on GH secretion had been largely eliminated in rats with ante rolateral deafferentation of the medial basal hypothalamus, it is high ly unlikely that the effects of hyperglycemia or hypoglycemia on GH se cretion were the consequence of altered SS secretion.