Elevated serum human growth hormone and decreased serum insulin in prediabetic males after intravenous tolbutamide and glucose

Abstract

A B S T R A C T Serum human growth hormone (HGH), serum immunoreactive insulin (IRI), plasma free fatty acids, and blood glucose were measured during intravenous glucose and intravenous tolbutamide tolerance tests in 13 normal and 13 prediabetic (offspring of two diabetic parents) males, closely matched for weight and age. Only prediabetics with normal glucose tolerance during oral, intravenous, and cortisone-primed glucose tolerance tests were evaluated.Mean serum HGH levels were significantly higher in prediabetics in response to intravenous tolbutamide and at the end of the 3-hr intravenous glucose tolerance tests (IVGTT). This is interpreted as a hyperresponsiveness of the growth hormone-releasing mechanisms in prediabetic subjects.The insulin response during the first 10 min of an IVGTT was significantly reduced in prediabetic males as compared to normal controls, whereas the insulin response to intravenous tolbutamide was not significantly different at the same time intervals in the same subjects.It appears, therefore, that measuring IRI during an IVGTT can be valuable in detecting the earliest signs of diabetes even before any disturbance of blood glucose homeostasis is seen.

Studies in prediabetes. Insulin response to oral glucose, intravenous tolbutamide and rapid intravenous glucose infusion in genetic prediabetics

“…levels after the glucose infusion previously reported by Camerini-Davalos et al [2], and more recently by Daweke et al [10] and Soeldner et al [24]. In close agreement with the experience of Boden et al [1], in our prediabetics the N.E.F.A. fasting values and their behaviour during the stimuli used did not exhibit any significant change when compared with the normals.…”

“…Again, after the injection of tolbutamide insulin secretion curve was closely parallel in normals and prediabetics in close agreement with the results reported by Boden eta/. [1] in 13 prediabetic males. On the other hand, the rapid intravenous glucose infusion unequivocally elicited in the prediabetics a markedly decreased insulin release in the first and third minutes after the stimulus.…”

“…Using these techniques a diminished and sluggish insulin release under the stimulus of the intravenously administered glucose has been described by some authors [3] as a distinctive character of the prediabetic subject. This failure in the insulin-releasing mechanism(s) has not been uniformly observed when the oral glucose load [13,19,7] or the intravenous tolbutamide test [1,4] was selected as the stimulus of the pancreatic beta cell. The implications of these findings in the understanding of the pathogenesis of the diabetes mellitus have been recently discussed by Luft [17].…”

Insulin and Growth Hormone Secretion Stimulated by Intravenous Administration of Arginine in the Low Insulin Responders (Prediabetes ?)

“…This fact is consistent with the findings of Soeldner et al (1970) and Boden et al (1968) who stated that growth hormone levels of prediabetes were higher than in the normal control. Serum growth hormone responses during arginine infusion were elevated in close male relatives of diabetic patients with normal glucose tolerance tests (Knopf et al 1969).…”

Glucose Tolerance, Serum Insulin and Lipid Abnormalities in Patients with Coronary Heart Disease

“…Furthermore, this hypothesis is unable to explain the increased incidence of coronary heart disease in patients with diabetes mellitus who have a diminished serum insulin response.4), 43) The significance of the abnormal metabolism (delayed insulin and FFA response to glucose, impaired glucose tolerance, and hyperlipidemia) in patients with coronary heart disease remains to be defined. When this is defined, the increased incidence of coronary heart disease in patients with diabetes mellitus may be also explained.…”