Dehydroepiandrosterone sulfate and bone resorption rates as reflected by serum levels of C-terminal telopeptide of type I collagen: a study in healthy men.

Sex steroid hormones contribute to the physiological regulation of bone turnover in males. To address this issue, we investigated serum estradiol (E2), total testosterone (T), and DHEAS concentrations, along with serum levels of carboxy-terminal telopeptide of type I collagen (sCTx), in a sample of 76 healthy men aged 23 to 87. The concentration of sCTx declined with age. Both T and DHEAS, at variance with E2, showed a significant age-related decline. T, DHEAS and sCTx significantly (p<0.01) correlated with each other. DHEAS and T were significantly associated after correcting for age (r=0.35, p=0.002) or body mass index (r=0.65, p<0.0001). DHEAS, but not T, significantly correlated with sCTx after correcting for age (r=0.26, p=0.026, and r=0.20, p=0.08, respectively). Stepwise multiple regression analysis showed that only DHEAS (but not T or E2) was a significant independent predictor of sCTx (p=0.0001). Our results show that adrenal androgens play a crucial role in regulating bone resorption in aging men.

The G-308A variant of the Tumor Necrosis Factor-alpha (TNF-alpha) gene is not associated with obesity, insulin resistance and body fat distribution.

BACKGROUND: Tumor Necrosis Factor-alpha (TNF-alpha) has been implicated in the pathogenesis of insulin resistance and obesity. The increased expression of TNF-alpha in adipose tissue has been shown to induce insulin resistance, and a polymorphism at position -308 in the promoter region ofTNF-alpha has been shown to increase transcription of the gene in adipocytes. Aim of this study is to investigate the role of the G-308A TNFalpha variant in obesity and to study the possible influence of this mutation on body fat distribution and on measures of obesity (including Fat Free Mass, Fat Mass, basal metabolic rate), insulin resistance (measured as HOMAIR), and lipid abnormalities. The G-308A TNFalpha polymorphism has been studied in 115 patients with obesity (mean BMI 33.9 +/- 0.5) and in 79 normal lean subjects (mean BMI 24.3 +/- 0.3). METHODS: The G-308A variant, detected by PCR amplification and Nco-1 digestion, determines the loss of a restriction site resulting in a single band of 107 bp [the (A) allele]. RESULTS: The (A) allele frequencies of the G-308A TNFalpha polymorphism were 13.1% in the obese group and 14.6% in the lean subjects, with no significant difference between the two groups. Furthermore, no association was found with BMI classes, body fat distribution, HOMAIR, and metabolic abnormalities. CONCLUSIONS: Our study did not detect any significant association of the G-308A TNFalpha polymorphism with obesity or with its clinical and metabolic abnormalities in this population. Our data suggests that, in our population, the G-308A TNFalpha polymorphism is unlikely to play a major role in the pathogenesis of these conditions.

Hormone metabolism in the pulmonary circulation.

We measured hormonal levels in blood samples from pulmonary and radial arteries in 117 patients undergoing aorto-coronary by-pass surgery with the aim of investigating the role of the pulmonary vessel endothelium in hormone metabolism. Insulin and glucagon concentrations were significantly higher in pulmonary artery blood with respect to radial artery blood (73 +/- 65 vs. 65 +/- 47 pmol/l, p < 0.005, and 80 +/- 49 vs. 73 +/- 51 ng/l, p < 0.01, respectively), while no difference was found for growth hormone, prolactin, C peptide, insulin-like growth factor I, follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, parathyroid hormone, thyroglobulin, triiodothyronine, thyroxine, free triiodothyronine, and free thyroxine. Moreover, prolactin concentrations were more than twice the normal levels, this being an effect of propafol and the opiate fentanyl used for the general anesthesia. Assuming that the arteriovenous differences observed are a marker of peptide hormone degradation, our study has demonstrated that with similar kinetics insulin and glucagon secreted into portal circulation and escaping from hepatic extraction undergo further homeostatic removal of about 9-10 % in the pulmonary circulation before entering the general circulation.

Autoantibody negative new onset type 1 diabetic patients lacking high risk HLA alleles in a caucasian population: are these type 1b diabetes cases?

BACKGROUND: In Caucasians, a small number of Type 1 diabetic patients do not show evidence of humoral islet autoimmunity at disease onset, at least with common screening procedures. In African- and Hispanic-American diabetic children at time of diagnosis, many show no evidence of autoimmunity but have an atypical clinical form of the disease. According to the recent American Diabetes Association classification, this subgroup of autoantibody negative patients is referred to as Type 1b diabetic subjects. In the present study, a homogeneous Caucasian Type 1 diabetic clinic-based cohort has been evaluated at diagnosis using a large panel of diabetes-related antibodies and then characterized for various genetic features in order to identify newly diagnosed Type 1 diabetics who are potentially autoantibody negative, i.e. possibly referrable to as idiopathic Type 1b diabetes. METHODS: Newly diagnosed Type 1 diabetic patients of Italian origin (n=141, mean age 12.0+/-7.6 years) were tested for anti-islet cell, anti-insulin, anti-65 kDa isoform of glutamic acid decarboxylase and anti-amino acid residues 256-979 of the tyrosine-phosphatase IA-2 molecule autoantibodies (Step 1). Only those patients found to be autoantibody negative were tested for anti-disialo-ganglioside GD3, anti-thyroid peroxidase, anti-thyroglobulin, anti-21-OH hydroxylase, anti-gastric parietal cell and anti-transglutaminase antibodies (Step 2). Sera negative for the presence of these six autoantibodies as well were characterized in terms of HLA DRB1, DQB1 and CTLA-4. RESULTS: Six out of 141 subjects (3.5%) were autoantibody negative in the first step of the study and five out of six in the second. These five autoantibody negative patients underwent genetic analysis. Three of them had at least one Type 1 diabetes-related high risk HLA haplotype (3/141, 2.1%) while the remaining two cases showed neutral (DR5-DQB1*0301/DR5-DQB1*0301) or strongly protective (DR2-DQB1*0602/DR2-DQB1*0602) HLA genotypes, respectively (2/141, 1. 4%). CONCLUSIONS: Clinically defined Type 1 diabetic patients with no sign of autoimmunity do exist in a Caucasian population. These patients (2 out of 141) that cannot be classified as Type 1a diabetic patients lack clinical characteristics of Type 1b diabetes and have to be reconsidered for a more appropriate ADA classification. These data suggest the need of further large population-based studies to understand if Type 1b diabetes really occurs in a Caucasian population. The patient with a strongly protective HLA genotype is particularly interesting considering that among Caucasians only a few sporadic cases with Type 1 diabetes and DQB1*0602, have been reported, none of whom was homozygous at DQB1 locus.

[New prospects in the therapeutic use of somatostatin and its derivatives]. / Nuove prospettive nell'uso terapeutico della somatostatina e dei suoi derivati.

The discovery and subsequent clinical application of somatostatine, a polypeptide neurohormone of 14 amino acids, and of its analogs, opens a novel chapter of neuroendocrinology that is still in full evolution and to a large extent unknown. The isolation of an octapeptide, a selective somatostatine analog, permits to prolong its action, in fact it has a halflife of about 140 min in old subjects and about 100 min. in the young. Thanks to its excellent tolerability, the synthetic hormone can be usefully applied in the treatment of acromegaly, gigantism and hypersomatotropinemic conditions in general, and even in other clinical branches, such as treatment of esophageal hemorrhage due to the rupture of varices in liver cirrhosis or to erosion of gastric blood vessels in patients suffering from peptic ulcer disease.

[Endocrine aspects of puberty. Modifications of gonadotropins (LH, FSH), testosterone and cortisol circulating after ACTH and synthetic LH-RH]. / Aspetti endocrini della pubertà. Modificazioni delle gonadotropine (LH, FSH), testosterone e cortisolo circolanti dopa ACTH e LH-RH sintetico.

The effect of synthetic LH-RH (Relisorm Serono: 25 microgram i.v.) on plasma LH, FSH and testosterone was examined in 19 normal pubescent and prepubescent boys. Changes in cortisol and testosterone after 0.25 mg/m2 body surface ACTH (Synacthen ciba) was assessed in a further 8 prepubescent subjects. Notable amounts of FSH, LH and testosterone were noted in prepubescent subjects, pointing to hormonal production prior to sexual maturation. There was a prompt and significant increase in LH in all cases. In prepubescent subjects, this was accompanied by marked increases in FSH on some occasions, though no appreciable change in circulating testosterone. This suggests that the hypophyseal reserve of LH is sufficient in puberty. Prepubescent subjects displayed a significant rise in cortisol 30' and 60' after ACTH, whereas testosterone fell with respect to the start values. The results indicate that acute stimulation of the adrenal cortex before puberty leads to testosterone suppression.