Serum growth hormone

High doses of caffeine produce a stresslike neuroendocrine response (Spindel 1984 Spindel et al. 1984). This includes increased levels of corticosterone, jS-endorphin, and decreased serum growth hormone and thyrotropin-stimulating hormone in the rat. However, similar effects are not observed in humans until approximately 500 mg is consumed, the equivalent of 5 cups of coffee. At this dose in humans, elevations are seen in adrenocorticotrophic hormone, jS-endorphin, and cortisol. 

Mechanism of Action A dopamine agonist that directly stimulates dopamine receptors in the corpus striatum and inhibits prolactin secretion. Also suppresses secretion of growth hormone. Therapeutic Effect Improves symptoms of parkinsonism, suppresses galactorrhea, and reduces serum growth hormone concentrations in acromegaly. 

LH-RH in hypothalamus Pituitary content of FSH, LH and prolactin Blood levels of FSH, LH and prolactin Testosterone content in testes and serum Growth hormone in pituitary and serum... 

Serum growth hormone levels were dose-dependently increased after oral and intravenous administration. Moreover, an increase of insulin-like growth factor and serum cortisol was found. Clearly, the pituitary incubation method can only identify compounds which are suitable for further in vivo characterization, because the responses found in test animals at the target organ level are vast different from those found at the pituitary cell level. 

Earll JM, Sparks LL, Forsham PH. Glucose suppression of serum growth hormone in the diagnosis of acromegaly. JAMA 1967 20T.628-30,... 

Reiter EO, Morris AH, MacGillivray MH, Weber D. Variable estimates of serum growth hormone concentrations by different radioassay systems. J Clin Endocrinol Metab 1988 66 68-71. 

Fukada, H., M. Ban, H. Chiba and A. Hara. Immune complex transfer two-site chemiluminescent immunoassay for serum growth hormone in alevin chum salmon. J. Biolumin. Chemilumin. 13 107-111, 1998. 

H8. Hansen, A. P., Abnormal serum growth hormone response to exercise in juvenile diabetics. J. Clin. Invest. 49, 1467-1478 (1970). 

Riggs et al. (R20) showed that patients with acromegaly had normal serum alkaline phosphatase values. Stepan et al. (S66), similarly, found that hyperphosphatasemia is often absent in acromegaly. However, significantly elevated levels of the bone isoenzyme were demonstrated in 84 % of patients with elevated serum growth hormone values (S66). 

Serum growth hormone level is usually increased, mainly owing to decreased metabolic clearance (S7). Somatomedin levels are normal by radioimmunoassay (Tl), but the activity is decreased on bioassay, perhaps because of the presence of a low-molecular-weight inhibitor in the serum. The decreased somatomedin activity may contribute to the protein catabolic state, is inversely related to the BUN and serum creatinine levels, and may improve during dialysis (P12). 

Kirghgessner M and Roth HP (1985) Influence of zinc depletion and zinc status on serum growth hormone levels in rats. Biol Trace Elem Res 7 263 -268. 

Waxman, D.J., J.J. Morrissey, J.N. MacLeod, and B.H. Shapiro (1990). Depletion of serum growth hormone in adult female rats by neonatal monosodium glutamate treatment without loss of female-specific hepatic enzymes P450 2d (I1C12) and steroid 5 alpha-reductase. Endocrinology 126, 712-720. 

Baumann G, Shaw M A, Brumbaugh R C, et al. (1991). Short stature and decreased serum growth hormone-binding protein in the Mountain Ok people of Papua New Guinea. J. Clin. Endocrinol. Metab. 72 1346-1349. 

There are no comparable experimental points below 10 (0.1 ppb) but continuation of the exponential relationship is expected. Some partial studies have been made of methods for dioxins, partial in the sense that either the cleanup or the mass spectrometry has been studied collaboratively but not both together as consecutive steps in a single procedure. The data thus far suggest a CV of about the anticipated 100 at 10 ppt. Even radioimmunoassays appear to correspond to the precision curve. Hunter and McKenzie (15) report what appears to be a final average between-laboratory CV of approximately 30j in the United Kingdom national quality control scheme for the examination of serum growth hormone at the 5-100 ppb level by radioimmunoassay. 

Hunter, W. M. McKenzie, I. Quality control of radioimmunoassays for proteins The first two and half years of a national scheme for serum growth hormone measurements. Ann. Clin. Biochem. 1979, I6, 131-146. 

Irie, M., and Tsushima, T., Increase in serum growth hormone concentration following th3o-otropin releasing hormone injection in patients with acromegaly or giantism. /. Clin. Endocrinol. Metab. 35, 97—100 (1972). 

Syvalahti E, Pihlajamaki K, lisalo E. Effect of tuberculostatic agents on the re onse of serum growth hormone and immunoreactive insulin to intravenous tolbutamide, andonthehalf-life of tolbutamide, IntJ Clin Pharmacol Biopharm ( 916) 13, 83-9. 

Melmed S, Cook D, Schopohl J, Goth MI, Lam KS, Marek J. Rapid and sustained reduction of serum growth hormone and insulin-like growth factor-1 in patients with acromegaly receiving lanreotide Autogel therapy a randomized, placebo-controlled,... 

Integrated Concentrations of Serum Growth Hormone (ng/min/mM) for 180 minutes after Ingestion of the Treatment or Infusion of rhGH... 

Lambert MI, Hefer JA, Millar RP, Macfarlane PW. Failure of commercial oral amino acid supplements to increase serum growth hormone concentrations in male bodybuilders. Int J Sport Nutr 1993 3 298-305. 

Animal experiments have shown caffeine-mediated effects at the neuroendocrine level, such as increased serum corticosterone and /3-endorphin and decreased serum growth hormone and thyrotropin, but it is expected that habitual human consumption has only marginal or inconsistent neuroendocrine effects. Caffeine is described as a central nervous system (CNS) stimulant, and the increased formation and release of neurotransmitters such as catecholamines. 

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