Role of GH in regulating nocturnal rates of lipolysis and plasma mevalonate levels in normal and diabetic humans

1992 ◽  
Vol 263 (1) ◽  
pp. E168-E172 ◽  
Author(s):  
P. J. Boyle ◽  
A. Avogaro ◽  
L. Smith ◽  
D. M. Bier ◽  
A. S. Pappu ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Fatty Acid ◽  
Cholesterol Synthesis ◽  
Gh Deficiency ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Normal Subjects ◽  
Nonesterified Fatty Acid ◽  
Rate Limiting Step ◽  
Nocturnal Increase

To define the role that nocturnal increments in growth hormone (GH) play in maintaining lipolysis, glycerol turnover was measured in six patients with GH deficiency and six normal subjects during sleep. Glycerol production initially decreased in both groups but then increased to 1.44 +/- 0.20 mumol.kg-1.min-1 by 0800 h in normal subjects, whereas GH deficiency was associated with a continuous fall to 0.77 +/- 0.10 mumol.kg-1.min-1, P less than 0.02. Nonesterified fatty acid levels paralleled these changes. Six GH-deficient patients received basal GH replacement including a pulse during sleep, which resulted in normal fasting fatty acid levels (P less than 0.05, replaced vs. chronic deficiency). To assess a possible link between the normal nocturnal increase in plasma mevalonate (the product of the rate-limiting step in cholesterol synthesis) and sleep-associated GH release, 11 GH-deficient patients and 11 normal subjects were studied. Peak nocturnal and fasting mevalonate concentrations were not correlated with GH level. We conclude that nocturnal growth hormone secretion is essential for maintaining lipolysis but that it is not related to normal increments in mevalonate and, by inference, to cholesterol synthesis during sleep

Effect of L-Tryptophan on Apomorphine-Induced Growth Hormone Secretion in Normal Subjects

1980 ◽  
Vol 13 (06) ◽  
pp. 331-335 ◽  
Author(s):  
S. Lal ◽  
S. Young ◽  
P. Cervantes ◽  
H. Guyda
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Normal Subjects

Test of growth hormone secretion in adults: poor reproducibility of the insulin tolerance test

1995 ◽  
Vol 133 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Hans C Hoeck ◽  
Peter Vestergaard ◽  
Poul E Jakobsen ◽  
Peter Laurberg
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Repeated Testing ◽  
Provocative Test ◽  
Insulin Tolerance ◽  
Gh Deficiency In Adults

Hoeck HC, Vestergaard P, Jakobsen PE, Laurberg P, Test of growth hormone secretion in adults: poor reproducibility of the insulin tolerance test. Eur J Endocrinol 1995;133:305–12. ISSN 0804–4643 The insulin tolerance test (ITT) is regarded as the most reliable provocative test in the diagnosis of growth hormone (GH) deficiency in adults. In the present study the test was evaluated by investigating the range of GH responses in normal adult males and females and the intra-individual reproducibility of the test. Sixteen healthy non-obese adults, eight males (median age 31.5 years) and eight females (median age 31.8 years) were tested twice with the ITT, with a minimum of 72 h between each test. The females were tested between day 3 and day 10 of their menstrual cycles. Adequate hypoglycemia was achieved in all cases with a median nadir blood glucose of 1.3 mmol/l (range 0.8–2.0). Growth hormone in serum was measured by immunoradiometric assay and low values were confirmed by a different assay. Median peak GH concentration responses to the ITT were: in males 27.9 μg/l, range 5.0–71.1 (test 1) and 30.5 μg/l, range 7.9–69.5 (test 2); and in females 9.0 μg/l, range 4.1–17.9 (test 1) and 8.4 μg/l, range 0.09–42.4 (test 2). The rise in GH concentration during the ITT was higher in males than in females. In the males, all stimulated GH values were ≥5.0 μg/l. In the females, four out of 16 tests gave values below 5.0 μg/l and in one test the GH value was around the detection limit of the assays. There was poor reproducibility during repeated testing, with no correlation between the results of the two tests. The results did not correlate to the magnitude of the hypoglycemia. The results of this study illustrate the complexity of the regulation of GH secretion and indicate that the ITT is less useful for diagnosing GH deficiency in adults than previously anticipated. The diagnosis of GH deficiency in adults and especially in adult females should not be based on the results of a single ITT alone. Hans C Hoeck, Department of Endocrinology, Aalborg Regional Hospital, Reberbansgade, DK-9000 Aalborg, Denmark

DIFFERENT EFFECTS OF EXOGENOUS CYCLIC ADENOSINE MONOPHOSPHATE AND ITS DIBUTYRYL DERIVATIVE ON PLASMA GROWTH HORMONE, GLUCOSE, INSULIN AND CORTISOL

1976 ◽  
Vol 83 (1) ◽  
pp. 15-25
Author(s):  
M. Vanderschueren-Lodeweyckx ◽  
W. Proesmans ◽  
E. Eggermont ◽  
R. Eeckels
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Normal Subjects ◽  
Immunoreactive Insulin ◽  
Plasma Growth Hormone ◽  
Hormone Levels ◽  
The Mean

ABSTRACT The effects of the infusion in four different dosages (0.001, 0.005, 0.02 and 0.2 mg/kg/min during 60 min) of cyclic 3′,5′-adenosine monophosphate and of its dibutyryl derivative on plasma growth hormone and on glucose, immunoreactive insulin and cortisol were studied in 38 normal subjects and in 10 patients with idiopathic hypopituitarism. In normal subjects cyclic 3′,5′-adenosine monophosphate provokes an increase in plasma growth hormone levels (only when a dosage of 0.2 mg/kg/min is used) without any changes in plasma glucose, insulin and cortisol. The maximal value of the means is observed 75 min after starting the infusion. Dibutyryl cyclic 3′,5′-adenosine monophosphate (0.2 and 0.02 mg/kg/min) provokes a dose-related rise in plasma growth hormone levels which is always preceded by hyperglycaemia and hyperinsulinaemia. The peak of the mean growth hormone levels occurs at 135 min after initiation of the infusion. In all but one hypopituitary patients the nucleotides do not promote growth hormone secretion. It is concluded that exogenous cyclic 3′,5′-adenosine monophosphate and its dibutyryl derivative may not be considered as analogous and that both compounds may contribute to study growth hormone release in normal subjects and in patients with growth abnormalities.

Exercise Provocation Test for Growth Hormone Secretion: Methodologic Considerations

2008 ◽  
Vol 20 (4) ◽  
pp. 370-378 ◽  
Author(s):  
Alon Eliakim ◽  
Dan Nemet
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Current Knowledge ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Provocation Test ◽  
Pharmacological Agents ◽  
Laboratory Exercise ◽  
Gh Secretion ◽  
Artificial Nature

The diagnosis of Growth Hormone (GH) deficiency in children with short stature is complex, and in certain cases, might be very difficult. Most of the provocative tests used to evaluate GH deficiency use pharmacological agents. The artificial nature of the pharmacological tests and the possibility that these tests might not always reflect GH secretion under normal physiological conditions provides the impetus for a more physiologic test. Exercise is one of the important GH releasing physiological stimuli. This review will summarize the current knowledge on the methods for performing laboratory exercise provocation test for GH secretion in children. In addition to recommendations of more standardized exercise protocols and environmental considerations, we will also focus on GH responses to exercise in unique populations such as obese children.

Demonstration of a role for growth hormone in glucose counterregulation

1989 ◽  
Vol 256 (6) ◽  
pp. E835-E843 ◽  
Author(s):  
P. De Feo ◽  
G. Perriello ◽  
E. Torlone ◽  
M. M. Ventura ◽  
F. Santeusanio ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Plasma Glucose ◽  
Glucose Utilization ◽  
Hepatic Glucose Production ◽  
Hormone Secretion ◽  
Plasma Catecholamines ◽  
Growth Hormone Secretion ◽  
Glucose Production ◽  
Plasma Free Fatty Acid ◽  
Normal Subjects

To test the hypothesis that growth hormone secretion plays a counterregulatory role in prolonged hypoglycemia in humans, four studies were performed in nine normal subjects. Insulin (15 mU.M-2.min-1) was infused subcutaneously (plasma insulin 27 +/- 2 microU/ml), and plasma glucose decreased from 88 +/- 2 to 53 +/- 1 mg/dl for 12 h. In study 1, plasma glucose, glucose fluxes (D-[3-3H]glucose), substrate, and counterregulatory hormone concentrations were simply monitored. In study 2 (pituitary-adrenal-pancreatic clamp), insulin and counterregulatory hormone secretions (except for catecholamines) were prevented by somatostatin (0.5 mg/h iv) and metyrapone (0.5 g/4 h po), and glucagon, cortisol, and growth hormone were reinfused to reproduce the concentrations of study 1. In study 3 (lack of growth hormone increase), the pituitary-adrenal-pancreatic clamp was performed with maintenance of plasma growth hormone at basal levels, and glucose was infused whenever needed to reproduce plasma glucose concentration of study 2. Study 4 was identical to study 3, but exogenous glucose was not infused. Isolated lack of a growth hormone response caused a decrease in hepatic glucose production and an increase in glucose utilization that resulted in an approximately 25% greater hypoglycemia despite compensatory increases in plasma catecholamines. Plasma free fatty acid, 3-beta-hydroxybutyrate, and glycerol concentrations were reduced approximately 50%. It is concluded that growth hormone normally plays an important counterregulatory role during hypoglycemia by augmenting glucose production, decreasing glucose utilization, and accelerating lipolysis.

Galanin does not affect the growth hormone-releasing hormone-stimulated growth hormone secretion in patients with hyperthyroidism

1992 ◽  
Vol 127 (6) ◽  
pp. 504-508 ◽  
Author(s):  
Andrea Giustina ◽  
Anna Rosa Bussi ◽  
Fabio Legati ◽  
Simonetta Bossoni ◽  
Massimo Licini ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Random Order ◽  
Normal Subjects ◽  
Graves Disease ◽  
Growth Hormone Releasing Hormone ◽  
Gh Secretion ◽  
Hyperthyroid Patients ◽  
Secretory Capacity

Patients with hyperthyroidism have reduced spontaneous and stimulated growth hormone (GH) secretion. The aim of our study was to evaluate the effects of galanin, a novel neuropeptide which stimulates GH secretion in man, on the GH response to GHRH in patients with hyperthyroidism. Eight untreated hyperthyroid patients with Graves' disease (6F, 2M, aged 25–50 years) and six healthy volunteers (3F, 3M, aged 27–76 years) underwent from - 10 to 30 min in random order: (i) porcine galanin, iv, 500 μg in 100 ml saline; or (ii) saline, iv, 100 ml. A bolus of human GHRH(1-29)NH2, 100 μg, was injected iv at 0 min. Hyperthyroid patients showed blunted GH peaks after GHRH+saline (10.2±2.5 μg/l) compared to normal subjects (20.7±4.8 μg/l, p< 0.05). GH peaks after GHRH+ galanin were also significantly lower in hyperthyroid subjects (12.5±3 μg/l) compared to normal subjects (43.8±6 μg/l, p<0.05). That galanin is not able to reverse the blunted GH response to GHRH in hyperthyroidism suggests that hyperthyroxinemia may either increase the somatostatin release by the hypothalamus or directly affect the pituitary GH secretory capacity.

INFLUENCE OF SERUM FREE FATTY ACID LEVELS ON GROWTH HORMONE SECRETION IN LACTATING COWS

1975 ◽  
Vol 66 (2) ◽  
pp. 213-224 ◽  
Author(s):  
R. REYNAERT ◽  
M. DE PAEPE ◽  
S. MARCUS ◽  
G. PEETERS
Keyword(s):  
Growth Hormone ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Nicotinic Acid ◽  
Glucose Concentration ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Direct Consequence ◽  
Serum Free Fatty Acid ◽  
Lactating Cows

SUMMARY The influence of intravenous injections or infusions of insulin (0·2 i.u./kg), propranolol (150 mg), 3,5-dimethylpyrazole (3 mg/kg), 3,5-dimethylisoxazole (0·08 mg/kg), glucose (0·5 g/kg), nicotinic acid (120 mg/kg), arginine (0·5 g/kg) or butyrate (0·5 mmol/kg) on plasma glucose levels, and on serum concentrations of growth hormone and free fatty acids of lactating cows was investigated. In all of these experiments we noted an increase in the level of growth hormone. This increase was not a direct consequence of alterations in the glucose concentration, since the growth hormone peak occurred both during a decrease (insulin, 3,5-dimethylisoxazole, nicotinic acid and butyrate tests), and during an increase of the glucose level (glucose, arginine and propranolol tests), whereas the glucose concentration remained unchanged during the 3,5-dimethylpyrazole experiments. However, in each instance a precipitous fall of the free fatty acid level was noted. The glucose, growth hormone, and free fatty acid levels of lactating cows were not affected by either i.v. injection or infusion of saline.

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