Plasma Growth Hormone, Insulin, and Glucagon Responses to Arginine Infusion in Children and Adolescents with Idiopathic Short Stature, Isolated Growth Hormone Deficiency, Panhypopituitarism, and Anorexia Nervosa

Abstract

ExtractThe effects of intravenous infusion of arginine (20 g/m2) after an overnight fast on plasma immunoreactive growth hormone (GH), insulin (IRI), and glucagon (IRG), and blood glucose were examined in five groups of children and adolescents: 10 normal individuals, 18 with idiopathic short stature, 6 with isolated growth hormone deficiency, 8 with panhypopituitarism, and 6 with anorexia nervosa.The mean fasting plasma GH concentration was significantly elevated in the group with anorexia nervosa (P < 0.05), and similar to the value for the normal group in all other groups. After arginine infusion, four-to sixfold increases of plasma G H were observed in the normal children, and similar increases were seen in those with idiopathic short stature as well as in those with anorexia nervosa; whereas, in the children with isolated growth hormone deficiency or panhypopituitarism, there was no significant increase in plasma GH. Fasting blood glucose concentrations were significantly lower than normal in subjects with isolated growth hormone deficiency ( P < 0.05), panhypopituitarism ( P < 0.001), and anorexia nervosa (P < 0.001), whereas fasting plasma IRI and IRG concentrations were similar to the values in the normal group. Plasma IRI increased eightfold at the end of the 30-min arginine infusion in the normal subjects; the increase was slightly but not significantly less in those with idiopathic short stature, and significantly less in those with isolated growth hormone deficiency ( P < 0.05), panhypopituitarism ( P < 0.001), and anorexia nervosa ( P < 0.05). Arginine infusion resulted in two-to threefold increases of plasma IRG in the normal group, and similar increases were observed in all of the other groups tested. These results suggest that whereas pancreatic P cell responsiveness may be deficient in children and adolescents with isolated growth hormone deficiency, panhypopituitarism, or anorexia nervosa, pancreatic a cell responsiveness, to arginine a t least, appears to be intact under these conditions. SpeculationAlthough plasma glucagon responses to arginine infusion were not less in subjects with hypopituitarism or anorexia nervosa than in normal subjects, relative hypoglucagonemia may have existed, since both basal and postarginine infusion plasma glucagon levels were not higher than normal in the presence of significantly lower blood glucose values. Thus, the present study does not exclude a deficient pancreatic a cell response to hypoglycemia. Alternatively, nonavailability of substrates for gluconeogenesis may have a more important influence than hormonal factors in the genesis of the hypoglycenia observed in these states.73

Impaired glucagon secretion to insulin-induced hypoglycemia in anorexia nervosa

“…These results suggest that reduction in body weight and malnutrition appear to be major cau¬ sative factors of the observed pancreatic -cell dys¬ function. On the other hand, the glucagon re¬ sponse to arginine loading in patients with anore¬ xia nervosa was not significantly different from that in the control group and is consistent with previous reports (Sizonenko et al 1975;Blickle et al 1984). The difference in glucagon responses to the two different stimuli suggests that the -cell in anorectic patients is selectively unresponsive to a reduction in glucose concentrations, whereas the response to amino acid stimuli appears to be in¬ tact.…”

Stunted growth with more or less normal appearance

“…Insulin measurements after provocation tests with various stimuli have been published by several authors [34,128,129,251,265,317]. The results of Youlton et al [317] were ambiguous, especially since the control values were not given.…”

“…The results of Youlton et al [317] were ambiguous, especially since the control values were not given. Sizonenko et al found reduced responses to arginine, but no statistically significant differences [265]. Karp et al [128] tested 190 patients with arginine, of whom 80 exhibited a diminished insulin response, compared to healthy controls.…”

“…However, in view of the reduced secretion of GH and somatomedin which has been established during the last few years, it appears much more probable that the low insulin secretion is a secondary phenomenon and merely a consequence of the GH-deficiency. It has long been known that in hypopituitary dwarfs with complete lack of GH, provocation tests yield very low insulin surges [34,84,157,167,251,265]. Also with partial GH-deficiency insulin secretion is decreased, but not to this extent.…”

Sequentialer Arginin-Insulin-Test (SAIT) Eine sinnvolle Alternative zum isolierten Insulintoleranztest und Arginintest?

“…In der Literatur wurden bei Kindern mit GH-Mangel sowohl basal als auch 60 und 90 min nach dem Ende einer Arginininfusion signifikant niedrigere Blutzuckerwerte als bei gesunden Altersgenossen gemessen [4,6,15,17]. Somit scheinen diese Kinder sensibler auf Arginin zu reagieren und sind wohl gefährdeter, symptomatische Hypoglykämien zu entwickeln.…”