OBJECTIVE: To determine the normal values of serum IGF-1 (Immulite 2000) in a Brazilian adult (21-70 years) population. SUBJECTS AND METHODS: Healthy volunteers were divided into 10 groups according to age (5-year intervals), with 100 subjects (50 men and 50 women) per group. One-hundred participants were selected for repetition of the test after 12 weeks. RESULTS: No difference in IGF-1 values was observed between men and women, but a progressive reduction of serum IGF-1 with age was seen. The reference […]

OBJECTIVE: To evaluate the frequency of subclinical acromegaly (in the absence of clinical phenotype but biochemically uncontrolled) in patients with prolactinoma during treatment with dopaminergic agonists. SUBJECTS AND METHODS: One hundred twenty one patients without a phenotype suggestive of acromegaly were studied. RESULTS: Initially, the laboratory diagnosis of acromegaly was unequivocal (elevated IGF-1 for gender and age with nadir GH > 1 ?g/L) in two patients, and likely (elevated IGF-1 with nadir GH > cut-off but < 1 ?g/L) in […]

Growth, the main characteristic of childhood and adolescence, has a similar pattern in the majority of the individuals. Genetic background and GH-IGF axis are the factors that directly influence this process. Pituitary GH acts on growth mainly through the regulation of IGF system. The IGFs (IGF-1 and IGF-2) are growth factors produced in the majority of the organs and body tissues. They have autocrine, paracrine and endocrine actions on metabolism and cell proliferation, growth and differentiation. The IGFs bind with […]

The diagnostic approach to growth hormone deficiency (GHD) in children with short stature (SS) is controversial. Here we review the available methodology and present prospective data obtained in a cohort of patients with SS suggesting the use of screening test followed by the confirmation test. Thus, the children with SS should be submitted to clinical and laboratorial evaluation to exclude of chronic and genetic diseases. In addition patients with height < 3 percentil or growth velocity < percentil 25, IGF-1 […]

Treatment of hypogonadotropic hypogonadism in adult women with hypopituitarism can include a wide range of estrogen and progestogen treatment alternatives and oral administration is the route of least cost and greatest patient comfort. The oral estrogen route has a major impact on the growth hormone-insulin-like growth factor I (GH/IGF-1) axis. Oral estrogen therapy, when given concurrently with GH to patients with hypopituitarism, antagonizes the biological effects of GH treatment and aggravates the abnormalities of body composition and the metabolism in […]

The treatment of systemic diseases with glucocorticoids is often associated with decreased height velocity (HV), and can result in shorter final height. Interactions between adrenal and GH-IGF axis have been described and can occur at hypothalamic-pituitary level or at the regulation of IGF system, including the IGF1R signaling. The clinical state of these patients may be considered as an absolute and/or functional IGF-1 deficiency. Interventions aiming to restore the normal function of GH-IGF axis might reduce the glucocorticoids-induced growth suppression […]

Based on presumptions that the infusion of amino acids can augment the release of human growth hormone (hGH) and that this metabolism is related with secretion of insulin-like growth factor I (IGF-I), the purpose of this study was to verify the effect of L-arginine supplementation on GH and IGF-I in adults. Seventeen male individuals participated on the study and were randomized to receive L-arginine (n= 10) or placebo (n= 7), seven grams per day for seven days. Before and after […]

We describe a patient with macroprolactinoma and discrepant insulin-like growth factor (IGF-1) concentration (elevated) and growth hormone (GH) values during a 75 g oral glucose tolerance test (normal), that were measured to evaluate the co-secretion of GH by tumor. With the bromocriptin use, the patient achieved normalization of prolactin, but persisted with high levels of IGF1, suggesting to be subclinical acromegaly. After the development of new more sensitive GH assays, cases of discrepant GH and IGF-1 results have been observed […]

We evaluated GH, IGF-1 and IGFBP-3 concentrations in ten acromegalic patients before and after treatment with subcutaneous octreotide (OCT-sc) and long-acting octreotide (OCT-LAR). We also evaluated the acute and short-period treatment (post 21 days) with octreotide as an index to test tolerance and responsiveness to both formulations. Patients were also evaluated after 6 months of treatment with each drug. Pre-treatment fasting GH (µg/l; IFMA), GH nadir during oGTT and IGF-1 (µg/l; IRMA) levels were 13.9±6.3; 11.4±6.3; 717±107, respectively. Fasting GH […]

The extension of the life expectancy led to strategies aimed at improving the quality of life and productivity of aging persons. It is well known that, after the pubertal peak, the activity of the GH/IGF-1 axis progressively declines. Consequently, many normal individuals older than 60 years have 24-hour GH secretion indistinguishable from that of an adult patient with GH deficiency due to hypothalamic-pituitary lesions (ADGH). This physiological phenomenon is paralleled with many clinical aspects of ADGH, such as increased visceral […]

We have evaluated 70 patients with GH deficiency, 39 females and 31 males, ranging in age from 18 to 69 years (mean: 38.3±13.5), from 3 centers in Brazil. GH replacement dose was different among the centers, as well as IGF-1 response to GH, which was more pronounced in patients using the highest GH dose. GH replacement led to a significant increase of IGF-1 and HDL cholesterol, as well as bone mineral density (BMD) and to a significant decrease in total […]

Acromegaly is a characteristic clinical syndrome caused in most cases by a GH-producing pituitary macroadenoma. Tumoral GH hypersecretion results in skeletal changes, metabolic abnormalities, multi-systemic complications and a significant increase in the overall mortality. The diagnosis is suspected on clinical grounds, and it is normally confirmed by biochemical and radiological examinations. From the biochemical standpoint, the diagnostic approach for demonstration of GH excess involves either basal hormone measurements, mainly GH and insulin-like growth factor-1 (IGF-1), and endocrine tests, such as […]