SUMMARY Insulin resistance and elevated glucagon levels result in non-suppressible hepatic glucose production and hyperglycemia in patients with type 2 diabetes. The CREB co-activator complex controls transcription of hepatic gluconeogenic enzyme genes. Here we show that both the antidiabetic agent metformin and insulin phosphorylate the transcriptional co-activator CBP at serine 436 via PKCι/λ. This event triggers the dissociation of the CREB-CBP-TORC2 transcription complex and reduces gluconeogenic enzyme gene expression. Mice carrying a germline mutation of this CBP phosphorylation site (S436A) demonstrate resistance to the hypoglycemic effect of both insulin and metformin. Obese, hyperglycemic mice display hepatic insulin resistance, but metformin is still effective in treating the hyperglycemia of these mice since it stimulates CBP phosphorylation by bypassing the block in insulin signaling.

PRRT is well tolerated and very effective in advanced well-differentiated small intestinal (midgut) NET. A high disease control rate and long PFS can be achieved with this modality after failure of standard biotherapy with somatostatin analogues. Tumour functionality and high plasma CgA appear to be independent predictors of unfavourable patient outcome.

PRRT with (177)Lu-octreotate in the re-treatment setting is safe and effective in patients with metastatic GEP-NET.

Resistance to thyroid hormone (RTH) is most often due to point mutations in the ␤-isoform of the thyroid hormone (TH) receptor (TR-␤). The majority of mutations involve the ligand-binding domain, where they block TH binding and receptor function on both stimulatory and inhibitory TH response elements. In contrast, a few mutations in the ligand-binding domain are reported to maintain TH binding and yet cause RTH in certain tissues. We introduced one such naturally occurring human RTH mutation (R429Q) into the germline of mice at the TR-␤ locus. R429Q knock-in (KI) mice demonstrated elevated serum TH and inappropriately normal thyroid-stimulating hormone (TSH) levels, consistent with hypothalamic-pituitary RTH. In contrast, 3 hepatic genes positively regulated by TH (Dio1, Gpd1, and Thrsp) were increased in R429Q KI animals. Mice were then rendered hypothyroid, followed by graded T 3 replacement. Hypothyroid R429Q KI mice displayed elevated TSH subunit mRNA levels, and T 3 treatment failed to normally suppress these levels. T3 treatment, however, stimulated pituitary Gh levels to a greater degree in R429Q KI than in control mice. Gsta, a hepatic gene negatively regulated by TH, was not suppressed in R429Q KI mice after T 3 treatment, but hepatic Dio1 and Thrsp mRNA levels increased in response to TH. Cardiac myosin heavy chain isoform gene expression also showed a specific defect in TH inhibition. In summary, the R429Q mutation is associated with selective impairment of TH-mediated gene repression, suggesting that the affected domain, necessary for TR homodimerization and corepressor binding, has a critical role in negative gene regulation by TH.corepressor ͉ homodimer ͉ negative regulation ͉ resistance to thyroid hormone T hyroid-stimulating hormone (thyrotropin or TSH) is a heterodimeric glycoprotein consisting of 2 non-covalently linked protein subunits (TSH-␣ and TSH-␤), synthesized in the pituitary thyrotroph, which regulates the thyroid. TSH-releasing hormone (TRH) is synthesized in the paraventricular nucleus of the hypothalamus and released into the portal circulation, where it regulates the synthesis and glycosylation pattern (bioactivity) of pituitary TSH. The hypothalamic-pituitary-thyroid (HPT) axis is regulated by negative feedback involving thyroid hormones (THs) (T 4 and T 3 ), which are produced by the thyroid gland. The major negative regulator of TSH secretion is T 3 , which directly inhibits the transcription of the TSH-␣ and -␤ subunit genes (1-5) and TRH (6-8).TH action is mediated by different isoforms of the TH receptor (TR), which are members of the nuclear receptor superfamily of ligand-modulated transcription factors. Two genes, by alternative splicing and transcriptional start site utilization, express the known ligand-binding TR isoforms, TR-␣1, TR-␤1, TR-␤2, and TR-␤3. Negative regulation of the HPT axis is principally mediated by the ␤ isoform of the TR (9-13).On genes with a positive TH response element, TR interacts with corepressor proteins (CoRs) in the absence of ligand, and this...