WSB-1 is a SOCS-box-containing WD-40 protein of unknown function that is induced by Hedgehog signalling in embryonic structures during chicken development. Here we show that WSB-1 is part of an E3 ubiquitin ligase for the thyroid-hormone-activating type 2 iodothyronine deiodinase (D2). The WD-40 propeller of WSB-1 recognizes an 18-amino-acid loop in D2 that confers metabolic instability, whereas the SOCS-box domain mediates its interaction with a ubiquitinating catalytic core complex, modelled as Elongin BC-Cul5-Rbx1 (ECS(WSB-1)). In the developing tibial growth plate, Hedgehog-stimulated D2 ubiquitination via ECS(WSB-1) induces parathyroid hormone-related peptide (PTHrP), thereby regulating chondrocyte differentiation. Thus, ECS(WSB-1) mediates a mechanism by which 'systemic' thyroid hormone can effect local control of the Hedgehog-PTHrP negative feedback loop and thus skeletogenesis.

T(4), the main product of thyroid secretion, is a critical signal in plasma that mediates the TSH-negative feedback mechanism. As a prohormone, T(4) must be converted to T(3) to acquire biological activity; thus, type 2 iodothyronine deiodinase (D2) is expected to play a critical role in this feedback mechanism. However, the mechanistic details of this pathway are still missing because, counterintuitively, D2 activity is rapidly lost in the presence of T(4) by a ubiquitin-proteasomal mechanism. In the present study, we demonstrate that D2 and TSH are coexpressed in rat pituitary thyrotrophs and that hypothyroidism increases D2 expression in these cells. Studies using two murine-derived thyrotroph cells, TtT-97 and TalphaT1, demonstrate high expression of D2 in thyrotrophs and confirm its sensitivity to negative regulation by T(4)-induced proteasomal degradation of this enzyme. Despite this, expression of the Dio2 gene in TalphaT1 cells is higher than their T(4)-induced D2 ubiquitinating capacity. As a result, D2 activity and net T(3) production in these cells are sustained, even at free T(4) concentrations that are severalfold above the physiological range. In this system, free T(4) concentrations and net D2-mediated T(3) production correlated negatively with TSHbeta gene expression. These results resolve the apparent paradox between the homeostatic regulation of D2 and its role in mediating the critical mechanism by which T(4) triggers the TSH-negative feedback.

Kallmann syndrome (KS) describes the association of isolated hypogonadotropic hypogonadism with hypo/anosmia. A few KS patients may reverse hypogonadism after testosterone withdrawal, a variant known as reversible KS. Herein, we describe the first mutation in KAL1 in a patient with reversible KS and review the literature. The proband was first seen at 22 years complaining of anosmia and lack of puberty. His brother had puberty at 30 years and a maternal granduncle had anosmia and delayed puberty. On physical examination, he was P 2 G 1 , testes were 3 ml and bone age was 14 years. During 20 years of irregular testosterone replacement, he developed secondary sexual characteristics and testicular enlargement. At the age of 41 years, after stopping testosterone replacement for 5 months, his testes were 15 ml, serum testosterone, LH, and FSH responses to GnRH were normal, and his wife was pregnant. The molecular study revealed a cytosine insertion in exon 2 of KAL1, generating a frameshift at codon 75 and a premature stop at codon 85. The expected gene product is a truncated peptide with 85 of the 610 amino acids present in the wild-type protein. Fourteen cases of reversible KS have been described but the genotype was only studied in a single case showing a heterozygous fibroblast growth factor receptor type 1 (FGFR1) mutation. Considering the low prevalence of mutations in KAL1 or FGFR1 in KS, it is possible that these genotypes are more prevalent in reversible KS than in other KS patients, but additional studies are necessary to confirm this hypothesis.European Journal of Endocrinology 156 285-290

Context: Persistence of hypogonadism is common in male patients with prolactinomas under dopamine agonist (DA) treatment. Conventional therapy with testosterone causes undesirable fluctuations in serum testosterone levels and inhibition of spermatogenesis. Objective: To evaluate the use of clomiphene as a treatment for persistent hypogonadism in males with prolactinomas. Design: Open label, single-arm, prospective trial. Patients: Fourteen adult hypogonadal males (testosterone !300 ng/dl and low/normal LH) with prolactinomas on DA, including seven with high prolactin (range: 29-1255 mg/l; median: 101 mg/l) despite maximal doses of DA. Intervention: Clomiphene (50 mg/day orally) for 12 weeks. Measures: Testosterone, estradiol, LH, FSH, and prolactin were measured before and 10 days, 4, 8, and 12 weeks after clomiphene. Erectile function, sperm analysis, body composition, and metabolic profiles were evaluated before and after clomiphene. Results: Ten patients (71%), five hyperprolactinemic and two normoprolactinemic, responded to clomiphene (testosterone O300 ng/dl). Testosterone levels increased from 201G22 to 457 G37 ng/dl, 436G52, and 440G47 ng/dl at 4, 8, and 12 weeks respectively (0.001!P!0.01). Estradiol increased significantly and peaked at 12 weeks. LH increased from 1.7G0.4 to 6.2G2.0 IU/l, 4.5G0.7, and 4.6G0.7 IU/l at 4, 8, and 12 weeks respectively (0.001!P!0.05). FSH levels increased in a similar fashion. Prolactin levels remained unchanged. Erectile function improved (P!0.05) and sperm motility increased (P!0.05) in all six patients with asthenospermia before clomiphene. Conclusions: Clomiphene restores normal testosterone levels and improves sperm motility in most male patients with prolactinomas and persistent hypogonadism under DA therapy. Recovery of gonadal function by clomiphene is independent of prolactin levels.

Whereas many cardiac symptoms of thyrotoxicosis resemble those of the hyperadrenergic state, circulating catecholamines are reduced or normal in this condition. To test the hypothesis that the thyrotoxic heart is hypersensitive to catechol-amines, we studied beta-adrenergic signaling in a transgenic (TG) mouse in which the human type 2 iodothyronine deiodinase (D2) gene is expressed in myocardium. Because D2 converts T4 to T3, the active form of thyroid hormone, the D2 TG mouse exhibits mild, chronic thyrotoxicosis that is limited to the myocardium. In the current study, we determined that cAMP accumulation in response to either norepinephrine or forskolin treatment was increased in isolated ventricular myocardiocytes and membrane-enriched fractions prepared from these D2 TG hearts as compared with wild type. This increase in adenylyl cyclase (AC) Vmax could not be explained by changes in AC isoform expression or changes in the long or short forms of stimulatory G-protein Gsalpha, which were approximately 10% decreased in D2 TG membranes. However, Western analysis and ADP-ribosylation studies suggest that the increase in AC Vmax is mediated by a decrease in the expression of inhibitory G proteins (Gialpha-3 and/or Goalpha). These data suggest that cardiac thyrotoxicosis leads to increased beta-adrenergic responsiveness of cardiomyocytes via alterations in the regulatory G-protein elements of the AC membrane complex.

INTRODUCTIONC linically nonfunctioning pituitary adenomas (NFPA) are usually diagnosed due to compressive symptoms, most typically visual field abnormalities, headache and hypopituitarism. Hypogonadotropic hypogonadism in patients with NFPA is highly prevalent both at diagnosis and after conventional treatment with pituitary surgery and/or radiotherapy (1-5). Untreated hypogonadism decreases patient quality of life and fertility and increases cardiovascular risk (6-8).Male hypogonadal patients are usually treated with testosterone replacement, most often with intramusCopyright © ABE&M todos os direitos reservados. 267Arq Bras Endocrinol Metab. 2011;55/4 cular injections that require frequent applications and induce large fluctuations in serum testosterone levels, with corresponding fluctuations in patient energy, libido, sexual performance and mood. In addition, testosterone replacement has an inhibitory effect on spermatogenesis and fertility, which is undesirable in patients who want to have children (7,8).Clomiphene is a well-known selective estrogen receptor modulator that increases gonadotropin secretion via hypothalamic-pituitary action (9). Clomiphene has been extensively used in the evaluation of the gonadotropic axis and in the induction of ovulation. Clomiphene has also been shown to revert hypogonadotropic hypogonadism in several conditions, such as falciform anemia, uremia, alcohol and steroid abuse, and in the stimulation of gonadotropin secretion in patients with sulpiride-induced hyperprolactinemia and gonadotropin suppression (10-14). More recently, we have shown that clomiphene led to the recovery of gonadal function in most male patients with prolactinomas and persistent hypogonadism under dopamine agonist treatment, irrespective of prolactin levels (15). In this study, we evaluated the therapeutic potential of clomiphene in reverting hypogonadism in patients with conventionally treated NFPA. PATIENTS AND METHODS PatientsTwelve consecutive adult male patients with NFPA, previously treated with surgery with or without radiotherapy, seen during one year at the Neuroendocrine Unit of the Endocrinology Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, presented hypogonadotropic hypogonadism and were considered to be included the protocol. Hypogonadotropic hypogonadism was defined by total testosterone levels below 300 ng/dL (10.5 nmol/L), and normal/low LH levels after at least two months of surgery. Testosterone replacement was discontinued for at least two months before evaluation. Three patients were excluded from the study due to prostate disease, limitations in schedule, or cognitive deficit. Nine patients completed the study. Study designThis study was an interventional, open label, uncontrolled, single-arm, prospective trial with oral clomiphene citrate (Clomid ® , Medley, kindly provided by Dr. Enrico Repetto), 50 mg/day for 12 weeks, designed to assess the effects of the drug on serum testosterone levels of male patients with NFPA previously treated with surgery. Th...

Objective: To evaluate the impact of screening hyper and hypoglycemia measured by capillary glycemia and standard monitorization of hyperglycemic patients hospitalized in regular care units of Hospital Israelita Albert Einstein. Methods: The capillary glycemia was measured by the Precision PCx (Abbott) glucosimeter, using the PrecisionWeb (Abbott) software. The detection of hyper and hypoglycemia during the months of May/June were compared to those of March/April in 2009 and to the frequency of the diagnosis of diabetes in 2007. results: There was an increase in the glycemia screening from 27.7 to 77.5% of hospitalized patients (p < 0.001), of hyperglycemia detection (from 9.3 to 12.2%; p < 0.001) and of hypoglycemia (from 1.5 to 3.3%; p < 0.001) during the months of May/June 2009. According to this action 14 patients for each additional case of hyperglycemia and 26 cases for each case of hypoglycemia were identified. The detection of hyperglycemia was significantly higher (p < 0.001) than the frequency of registered diagnosis related do diabetes in the year of 2007. conclusions: the adoption of an institutional program of glycemia monitorization improves the detection of hyper and hypoglycemia and glycemia control in hospitalized patients in regular care units.

Kallmann syndrome (KS), the association of hypogonadotropic hypogonadism and anosmia, was described by Maestre de San Juan in 1856 and characterized as a hereditary condition by Franz Josef Kallmann in 1944. Many aspects such as pathogeny, phenotype and genotype in KS were described in the last fifteen years. The knowledge of this condition has grown fast, making it difficult to update. Here we review historical aspects of this condition and its discoverers and describe new findings regarding the embryogenesis of the olfactory bulb and GnRH secreting neuronal tracts that are important for understanding the association of hypogonadism and anosmia. Additionally, we describe the phenotypic and genotypic heterogeneity of KS, including five related genes (KAL-1, FGFR1, PROKR2, PROK2 e NELF), and discuss the function of each codified protein in migration and maturation of the olfactory and GnRH neurons, with data from in vitro and in vivo studies. Finally we describe the clinical phenotype of patients carrying these mutations.