Endocrine Abstracts

Iron participates in the Fenton reaction (Fe2++H2O2+H+→Fe3++•OH+H2O), the most basic reaction of oxidative stress. This transition metal is required to keep oxidative balance, although iron overload is associated with enhanced oxidative damage and cancer initiation. Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are also involved in oxidative processes, lipid peroxidation incl...

Serum IGF-I levels were measured in 547 non-hypopituitaric, non acromegalic healthy subjects of both sexes in Italy to develop reference values in relation to age and gender. Participant subjects were stratified in three age classes (25–39, 40–59 and≥60 years) and IGF-I assay was carried out by double-antibody radio immunoassay. The Pearson’s correlation coefficient between age and IGF-I values was calculated by sex and pre-defined age ranges. IGF-I levels...

Type II diabetic nephropathy (DN) has become the single most common cause of end-stage renal disease in the Western world. In previous studies we have shown a significant involvement of the GH-IGF-I axis in a mouse model of type I DM. The purpose of this study was to examine the endocrine and renal changes in GH-IGF-I axis key molecules in db/db mice, a model of type II DM lacking a functional leptin receptor. Obese (D) and lean (heterozygote) (C) animals were followed, beginn...

Use of somatostatin (SRIF) analogs in acromegaly indicates greater lowering of IGF-I than predicted from GH reduction. Studies using hypophysectomized rats suggest a direct SRIF action on GH-induced IGF-I, however, interpretation is complicated by effects of SRIF on other hormonal axes. In isolated rat hepatocytes we showed SRIF and octreotide to have a direct inhibitory effect, via hepatic SSTRs, on GH-induced IGF-I production. GH (500 ng/ml) caused ~4 fold induction of IGF-I...

3beta-hydroxysteroid dehydrogenase (3beta-HSD) expression is essential for the synthesis of all classes of steroid hormones, converting delta5beta-hydroxysteroids into hormonally active delta4-3-ketosteroids in NAD+-dependent reactions. Numerous 3beta-HSD isoforms have been described in mouse, rat, human and other mammals, all with distinct tissue and developmentally specific expression, distinct kinetics, with alternative substrate specificity...

Annexin I, a phospholipid and calcium binding protein, plays a well demonstrated role in the early delayed inhibitory feedback actions of glucocorticoids in the pituitary. Annexin I is localized in folliculostellate (FS) cells and glucocorticoids act on these cells to externalize annexin I at specific foci on FS cell processes (Chapman et al, 2002 Endocrinology, in press). Annexin I lacks a signal sequence to direct it into the secretory pathway and the foci of externalized an...

Background: Regular physical exercise during childhood and adolescence can promote growth and development of muscle and bone mass. Although physical exercise is closely linked to the anabolic function of the GH /IGF-I axis the real impact of resistance training on GH/IGF axis is still unclear. The kinetics of IGF-I and IGFBP-3 during chronic training is not fully understood yet and an initial catabolic phase followed by an later anabolic phase has been reported in swimmers.</p...

Background: Papillary thyroid carcinoma (PTC) is a well differentiated malignant tumour that usually has a good prognosis in vast majority of patients after thyroidectomy, suppressive hormonal, and radioiodine treatment. However 5–10% of PTC cases can develop local relapse and distant metastases.Purpose of study: To make a comparative morphological analysis of PTC in two groups of patients: i) with and ii) without local relapse (regional metastases)...

The Na+/I− symporter (NIS) is a key plasma membrane protein that mediates active I− uptake in the thyroid, lactating breast, and other tissues with an electrogenic stoichiometry of 2 Na+ per I−. In the thyroid, NIS-mediated I− uptake is the first step in the biosynthesis of the iodine-containing thyroid hormones, which are essential early in life for proper development of the central nerv...

In contrast to bone formation biomarkers, reliable bone resorption biomarkers have not been available in serum. Recently, automated measurement of C-terminal cross-linking telopeptide of type I collagen (CTX-I), has been promoted as a reliable indicator of bone resorption. The objective of the study was to examine the correlation of CTX-I, with the traditional urinary markers, N-telopeptide of type I collagen (NTX-I) and deoxypyridinoline (DPD) in a series of patients with Pag...