The Importance of Insulin-Like Growth Factor (Somatomedin) Measurements in the Diagnosis and Surveillance of Acromegaly*

Rieu, M; Girard, François; Bricaire, H; Binoux, M

doi:10.1210/jcem-55-1-147

Cited by 87 publications

(46 citation statements)

References 27 publications

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“…Results for basal GH concentration are difficult to analyze because of pulsatility, fluctuations over time and sleep, and paradoxical responses. Levels of circulating IGF-I, which is primarily produced by the liver in response to GH, vary to a much lesser extent and have been used as a criterion for cure since 1990 (41). Several studies have reported a strong correlation between these three criteria (12,37,41), but others have reported discrepancies between IGF-I and basal GH (28, 42) results.…”

Section: Discussionmentioning

confidence: 99%

“…Levels of circulating IGF-I, which is primarily produced by the liver in response to GH, vary to a much lesser extent and have been used as a criterion for cure since 1990 (41). Several studies have reported a strong correlation between these three criteria (12,37,41), but others have reported discrepancies between IGF-I and basal GH (28, 42) results. Kaltsas et al reported a good general correlation between GH and IGF-I but with many discrepancies between mean GH and IGF-I levels in individual patients (29).…”

Section: Discussionmentioning

confidence: 99%

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Clinical, hormonal and magnetic resonance imaging (MRI) predictors of transsphenoidal surgery outcome in acromegaly

Bourdelot

Coste

Hazebroucq

et al. 2004

European Journal of Endocrinology

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Objective: Progress in the treatment of acromegaly with drugs is making it necessary to improve the prediction of the outcome of transsphenoidal surgery. Design: We evaluated clinical, hormonal and radiologic predictors based on magnetic resonance imaging (MRI) of surgical outcome in patients with acromegaly. Methods: This retrospective analysis included 125 consecutive patients investigated for acromegaly in a single endocrine unit since the use of MRI imaging began (1988). Eighty-three of these patients (50 women) underwent transsphenoidal surgery and were investigated before and after surgery in our department. A neuroradiologist unaware of the surgical outcome analyzed the results of pituitary gland MRI investigations. Results: Surgical remission rates were 44%, 43%, 61% and 59% based on mean basal GH concentration under 2.5 mg/l, GH/oral glucose tolerance test (OGTT) of ,1 mg/l, GH/OGTT of , 2 mg/l or IGF-I concentration normal for age and sex respectively. In univariate logistic regression analysis with IGF-I concentration used as the criterion for cure, young age (P , 0.001), high IGF-I concentration before surgery (P , 0.01), high basal GH concentration before surgery (P , 0.02), and high nadir GH/OGTT before surgery (P ¼ 0.03) were predictors of poor outcome. The following results in standardized MRI analysis were associated with a higher probability of not being cured: adenoma greater than 15 mm in diameter (P , 0.02), infrasellar extension (P ¼ 0.04), suprasellar extension (P , 0.005) and invasive adenoma (0.02) according to MRI staging. MRI analysis of the intracavernous extension showed that stages above B2 (possible sinus extension with sign of invasion of the space below the carotid artery) were associated with a lower probability of postoperative normal GH plasma levels (P ¼ 0.01). In multivariate analysis, age, preoperative hormonal levels and adenoma size remained the major predictors of surgical outcome. Conclusions: This report provides the first evidence that detailed MRI analysis of adenoma size, location and potential invasion, together with preoperative clinical and hormonal parameters, can be used for the prediction of hormonal outcome after transsphenoidal surgery for acromegaly.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Clinical, hormonal and magnetic resonance imaging (MRI) predictors of transsphenoidal surgery outcome in acromegaly

Bourdelot

Coste

Hazebroucq

et al. 2004

European Journal of Endocrinology

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“…It clearly is not practicable to perform all these tests on every patient and on present evidence the TRH test looks the most promising (Arafah et al, 1980;Roelfsema et al, 1985). Whether the wider availability in the future of somatomedin C assays will affect the situation remains to be seen (Clemmons et al, 1979;Rieu et al, 1982;Wass et al, 1982).…”

Section: Criteria Of Curementioning

confidence: 99%

Acromegaly

Nabarro

1987

Clinical Endocrinology

500

303

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SUMMARY A personal series of 256 cases of acromegaly/gigantism seen over a 20‐year period from 1963 is described. The insidious nature of the condition resulted in delay in diagnosis which was often made by a doctor when seeing the patient for an unrelated problem. Other features which commonly led to the diagnosis being made were headache, change in appearance, carpal tunnel syndrome, amenorrhoea and diabetes. The Hardy system for grading the radiological appearance of the pituitary tumour was used. Widely invasive tumours were not common but tended to occur in patients with younger age of onset and high GH levels. The occurrence of various symptoms and clinical features was noted and the changes resulting from reducing the GH level to normal. The incidence of hypertension, but not of coronary artery disease, is increased and the blood pressure may be reduced following successful treatment. The effects on the upper and lower respiratory tract are reported as well as sleep apnoea and problems associated with anaesthesia. Skin manifestations included sweating, pigmented skin tags, acanthosis nigricans and cutis verticis gyrata. In the skeletal system the incidence of kyphoscoliosis and osteoarthritis especially of the hip is reported: the question of hip replacement is discussed. Diabetes mellitus disappeared in most cases if the acromegaly was cured. In men but not in women the incidence of colloid nodular goitre was increased as was hyperthyroidism in middle‐aged women. In two patients a parathyroid adenoma was present: hypercalcaemia was present in five additional patients, but the cause was not determined. The common occurrence of amenorrhoea in the younger women was noted, it was not always associated with hyperprolactinaemia, and often responded to successful treatment of the acromegaly. The association of acromegaly with hirsutism and galactorrhoea is confirmed. The incidence of impotence and loss of libido in the men is discussed: in a proportion of those in whom the acromegaly was cured, potency returned, but in a number depression occurred and what was believed to be psychogenic impotence persisted. Hyperprolactinaemia was found in 49 out of 151 patients with active acromegaly in whom the prolactin level was measured. Previous reports have indicated a doubling of death rates in acromegalics. In this series there were 47 deaths observed compared to 37.2 expected. The increased death rate was in women of all ages and in men under the age of 55. The increased deaths in the women were from cardiovascular and cerebrovascular causes and from breast cancer. To demonstrate cure it is emphasized that not only must the GH level be reduced to normal, but that suppression following a glucose load must be demonstrated and disappearance of abnormal responses for example to TRH, that would mark the persistence of adenoma cells, confirmed. Even so, late relapse may occur and GH levels should be checked regularly. Long‐term follow up (mean 9.4 years) of 102 patients after transsphenoidal surgery is reported. Eighteen pat...

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“…Serum or plasma IGF-I levels have been reported to show better correlation not only with disease activity but also with the degree of improvement in response to therapy.53, 54 However, other reports indicate that both GH and IGF-I measurements have a poor correlation with symptomatic improvement in treated acromegaly.P The apparent discrepancies between the various studies which attempt to correlate plasma IGF-I levels with either severity of the illness and or efficacy of treatment may be attributable to differences in assay methodology. In particular, some reports involve direct analysis of samples with the consequent interference of binding proteins, the levels of which may show gross variations in the acromegalic state.…”

Section: Influence Of Nutritionmentioning

confidence: 99%

The Measurement of Insulin-Like Growth Factor I: Clinical Applications and Significance

Teale

1986

Ann Clin Biochem

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Of the somatomedins so far measured, the selective quantitation of insulin-like growth factor I (IGF-I) appears to have the greatest potential in clinical diagnosis. There have been two approaches to the development of immunoassay systems. One type uses antibodies raised against synthetic fragments of IGF-I which exhibit cross-reactivity with the whole hormone. Such assay systems may be adequate for measuring normal adult plasma IGF-I levels, but the potential for the higher sensitivity required for detecting sub-normal plasma levels in young children is apparent only in methods using antibodies raised against the complete hormone. IGF-I in plasma exists as part of a high molecular weight complex in which it is bound to carrier proteins. The binding proteins may interfere with plasma IGF-I measurements by radioligand assays. Direct analysis of untreated plasma samples is claimed to be possible using disequilibrium assay conditions but in order to maximise assay sensitivity it is necessary to employ an initial extraction stage in order to eliminate binding protein interference. Whether the measurement of plasma IGF-I can or should be used in addition to, or as a replacement for, plasma growth hormone (GH) measurement in the clinical assessment of growth disorders remains a controversial issue. Available evidence indicates that a single, random plasma IGF-I level provides an accurate reflection of GH secretion. Adequate discrimination between the elevated levels in acromegaly and normal reference values has been demonstrated. However, in the investigation of growth-retarded children available radioimmunoassay (RIA) methods have proved only partially successful because of the age-related nature of normal plasma IGF-I concentrations. Existing assays appear capable of identifying sub-normal plasma levels after the age of approximately 4 years. In younger subjects an improvement in assay sensitivity is required in order to establish with greater accuracy the relevant normal ranges. Improvements in the identification of the particular lesion responsible for retarded growth in a child can be achieved by measurement of both plasma GH and IGF-I concentrations. The predictive value of the acute plasma IGF-I response to single-dose GH therapy may identify patients who will respond to long-term GH therapy. Better, more informed decisions on subsequent treatment may therefore be made. Apart from GH control, several other factors influence circulating IGF-I levels. Nutritional status can be assessed through reference to IGF-I analysis, overall catabolic or anabolic processes being associated with decreasing or increasing plasma IGF-I levels respectively.

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The Importance of Insulin-Like Growth Factor (Somatomedin) Measurements in the Diagnosis and Surveillance of Acromegaly*

Cited by 87 publications

References 27 publications

Clinical, hormonal and magnetic resonance imaging (MRI) predictors of transsphenoidal surgery outcome in acromegaly

Clinical, hormonal and magnetic resonance imaging (MRI) predictors of transsphenoidal surgery outcome in acromegaly

Acromegaly

The Measurement of Insulin-Like Growth Factor I: Clinical Applications and Significance

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