Preoperative growth hormone response to thyrotropin-releasing hormone and oral glucose tolerance test in acromegaly: A retrospective evaluation of 50 patients

Marinis, Laura De; Mancini, Antonio; Bianchi, Antonio; Gentilella, R.; Valle, Domenico; Giampietro, Antonella; Zuppi, Paolo; Anile, Carmelo; Maira, Giulio; Giustina, Andrea

doi:10.1053/meta.2002.32017

Cited by 24 publications

(20 citation statements)

References 29 publications

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“…Thyrotropin-releasing hormone (TRH) test A paradoxical rise after TRH administration is found in about 60% of acromegalic patients (between 45% and 80% in series of more than 10 subjects) [23,[36][37][38][39][40][41][42][43][44]. The response to TRH seems to be more frequent in patients who will respond to octreotide (17/11 vs. 3/13) [38] and in patients with a positive GH response (i.e.…”

Section: Other Dynamic Tests Used For Diagnosismentioning

confidence: 99%

Dynamic tests for the diagnosis and assessment of treatment efficacy in acromegaly

2008

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In the vast majority of cases, basal serum GH and IGF-1 levels are markedly increased in patients with obvious clinical signs and symptoms of acromegaly. The oral glucose tolerance test (OGTT) is useful for diagnosis in the minority of patients who have weak GH hypersecretion. The cutoff for a "normal" GH nadir in the OGTT remains to be agreed. The type of GH assay, its sensitivity, the type of standard used by the manufacturer, the patient's age and especially gender, must all be taken into account. Recent studies using new highly sensitive assays suggest an upper normal GH nadir of 0.71 microg/l for female healthy patients, but no "universal" cut-off has yet been defined for healthy males (from 0.057 to 0.25 microg/l). The 1 microg/l cutoff proposed for the diagnosis of acromegaly in a 2000 consensus should be abandoned in favor of a 0.30 microg/l cutoff. Clinicians should know which assay is used, together with its sensitivity and the standard, before making therapeutic decisions. A more pragmatic view should probably be adopted when assessing the treatment response. Indeed, if "cure" is defined not with the <1 microg/l GH nadir but on the basis of healthy control values, many patients will not be considered controlled. However, the clinical relevance of such goal (e.g. achieving GH nadir <0.4 microg/l rather than <1 microg/l) in terms of prognosis and prediction of outcome on long term is not firmly established. Thus, from a pragmatic point of view, achieving a normal age-adjusted IGF-1 level and a GH nadir below 1 microg/l during OGTT will probably remain relevant for defining remission and good disease control in terms of morbidity and mortality in acromegaly.

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Section: Other Dynamic Tests Used For Diagnosismentioning

confidence: 99%

Dynamic tests for the diagnosis and assessment of treatment efficacy in acromegaly

2008

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“…However, exactly where below 1 lg/L this cut off should be cannot be uniformly agreed upon because the data vary depending upon the GH assay used [57][58][59]. A number of studies support a cut off of 1 lg/L [59,[60][61][62] while others utilizing different assays suggest cut offs of 0.5 lg/L [60,63] or 0.25 lg/L [64]. An OGTT cut off of 0.3 lg/L has also been suggested with an assay that utilizes 2 monoclonal antibodies that are 22 K GH specific and standards that are calibrated to the recombinant human GH 22 K specific reference preparation 88/624 [54].…”

Section: Clinical Consequences Of Poor Comparability Of Gh Assay Resultsmentioning

confidence: 99%

Measurement of human growth hormone by immunoassays: Current status, unsolved problems and clinical consequences

Bidlingmaier

Freda

2010

Growth Hormone & IGF Research

108

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Measuring the concentration of growth hormone (GH) in blood samples taken during dynamic tests represents the basis for diagnosis of growth hormone related disorders, namely growth hormone deficiency and growth hormone excess. Today, a wide spectrum of immunoassays are in use, enabling rapid and sensitive determination of growth hormone concentrations in routine diagnostics. From a clinical point of view several difficulties exist with the use and interpretation of GH assay results in the assessment of GH related disorders: Many physiological factors such as fat mass, age and gender influence the outcome of dynamic tests, overall leading to significant inter-individual differences in GH responses. However, in addition to the physiological variability, considerable variability exists in GH assay results obtained by different immunoassays. Unfortunately, all the new technical advances in the field of GH measurement techniques have not reduced this methodological variability. To a large extent, the actual values reported for the GH concentration in a sample depend on the method used by the respective laboratory. Obviously, such discrepancies limit the applicability of consensus guidelines on diagnosis and treatment in clinical practice. This review summarizes current practices for GH measurement with respect to the methods used, their limitations and the clinical consequences of the existing heterogeneity in GH immunoassay results.

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“…This result seems to be better than those obtained with other dynamic tests already proposed as alternative diagnostic tools in acromegaly. In particular, a paradoxical GH response to thyrotropin-releasing hormone was demonstrated in 50–75% of patients with active acromegaly with conflicting results concerning the reliability of the test in predicting persistence of disease after neurosurgery [28,29,30]. Moreover, safety issues, as well as for OGTT in acromegalic patients with diabetes mellitus, have been raised for thyrotropin-releasing hormone use in patients with pituitary GH-secreting adenomas [31,32,33,34].…”

Section: Discussionmentioning

confidence: 99%

Biochemical Evaluation of Patients with Active Acromegaly and Type 2 Diabetes Mellitus: Efficacy and Safety of the Galanin Test

Mazziotti

Bonadonna²,

Doga³

et al. 2008

Neuroendocrinology

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The oral glucose tolerance test, which is considered the gold standard for the diagnosis of active acromegaly, should not be performed in the presence of basal hyperglycemia. Moreover, false-positive responses may occur in patients with diabetes mellitus. Galanin has previously been demonstrated to induce paradoxical inhibition of growth hormone (GH) secretion in most patients with active acromegaly. In this study, we assessed GH response to galanin infusion in a series of 17 consecutive patients with active acromegaly, 7 of whom had coexistent type 2 diabetes mellitus and 10 were without either diabetes mellitus or impaired tolerance to glucose. 6 acromegalic patients with diabetes mellitus (85.7%) and 7 without diabetes (70.0%) showed a decrease in serum GH values during galanin infusion (χ² 0.9; p = 0.6). The GH nadir occurred at a comparable time in the two groups of acromegalic patients. Moreover, the two groups showed no significant difference (p = 0.45) in ΔGH during galanin infusion. Galanin infusion did not induce any significant change in plasma glucose levels in both diabetic and non-diabetic patients with acromegaly. The results of our study provide evidence that the galanin test may be of value for the diagnosis of acromegaly in patients with type 2 diabetes mellitus.

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Preoperative growth hormone response to thyrotropin-releasing hormone and oral glucose tolerance test in acromegaly: A retrospective evaluation of 50 patients

Cited by 24 publications

References 29 publications

Dynamic tests for the diagnosis and assessment of treatment efficacy in acromegaly

Dynamic tests for the diagnosis and assessment of treatment efficacy in acromegaly

Measurement of human growth hormone by immunoassays: Current status, unsolved problems and clinical consequences

Biochemical Evaluation of Patients with Active Acromegaly and Type 2 Diabetes Mellitus: Efficacy and Safety of the Galanin Test

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