Circulating Insulin Concentrations,Smoking, and Alcohol Intake Are Important Independent Predictors of Leptin in Young Healthy Men

Objective : Leptin, an adipocyte-secreted hormone, has been shown to signal the status of energy stores to the brain, regulate energy homeostasis, and mediate the neuroendocrine response to food deprivation. Obesity is associated with increased leptin levels, and several hormones, including insulin and glucocorticoids, have been associated with leptin levels and expression in rodents. Although obesity has been strongly associated with increased leptin in humans, a significant percentage of leptin's variability remains unexplained. The role of endogenous hormones, demographic factors, or certain life-style factors in explaining the residual variability of leptin levels has not yet been clarified. We performed this cross-sectional study to document the relative importance of obesity, lifestyle factor, and endogenous hormones in determining serum leptin levels. Research Methods and Procedures : We measured serum concentrations of insulin, Cortisol, testosterone, growth hormone, and dehydroepiandrosterone sulfate; ascertained anthropometric, demographic, and lifestyle characteristics; and studied these variables in relationship to serum leptin concentrations in a sample of young healthy men. Results : Obesity and alcohol intake were independently and positively associated with circulating leptin concentrations. Additionally, cigarette smoking was negatively and independently associated with leptin concentrations. Finally, serum insulin concentration was an independent hormonal determinant of circulating leptin concentrations, whereas serum testosterone was negatively associated with leptin only by bivariate analysis. Discussion : We conclude that, in addition to obesity, cigarette smoking, alcohol intake, and serum insulin levels are associated with leptin levels in a population of healthy young men.     

Synthesis and biological activity of FGLamide allatostatin analogs with Phe3 residue modifications

A FGLamide allatostatin neuropeptide mimic ( H17 ) is a potential insect growth regulator which inhibits the production of juvenile hormone by the corpora allata. To find more evidence to reveal the structure–activity relationships of the Phe³ residue in the C‐terminal conserved pentapeptide and search for novel analogs with high activity, a series of Phe³ residue‐modified analogs were designed and synthesized using H17 as the lead compound. Bioassay using juvenile hormone (JH) production by corpora allata of the cockroach Diploptera punctata indicated that analogs 4 , 11 , and 13 showed strong ability to inhibit JH production in vitro, with IC₅₀ of 38.5, 22.5, and 26 nM, respectively. As well, the activity of analog 2 (IC₅₀: 89.5 nM) proved roughly equivalent to that of H17 . Based on the primary structure–activity relationships of Phe³ residue, we suggest that for analogs containing six‐membered aromatic rings, removing the methylene group of Phe³ or an o‐halogen or p‐halogen‐substituted benzene ring could increase the ability to inhibit biosynthesis of JH. This study will be useful for the design of new allatostatin analogs for insect management. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.     

长链非编码RNA与性激素依赖性肿瘤

随着基因测序技术与核酸定量分析技术的发展,近年的大量研究表明,长链非编码RNA (long non-coding RNA,LncRNA) 通过多种途径调控基因表达,具有调节细胞功能的重要作用。LncRNA的异常表达与肿瘤发生发展之间的联系被广泛关注。其中,关于LncRNA与3种最常见的性激素依赖性肿瘤乳腺癌、子宫内膜癌和前列腺癌的研究,揭示其在肿瘤细胞或组织中扮演着类似于原癌基因或抑癌基因的双重角色。并通过多种调控机制,参与癌细胞的侵袭、增殖、转移等过程。因性激素受体分布的特异性,使得与之相关的多种LncRNA的表达也具有较高的特异性。本文总结LncRNA与乳腺癌、子宫内膜癌和前列腺癌的相关研究进展,包括涉及到的LncRNA种类、表达差异、作用机制及作为生物标志物或治疗靶点的可行性评价。     

Construction of recombinant plasmids containing rat thyroglobulin mRNA sequences

Two plasmids containing rat thyroglobulin cDNA sequences have been constructed and characterized. A plasmid with a 500-bp insert (pRT6) was isolated and identified as thyroglobulin-specific on the basis of the tissue specificity of the inserted sequence and of its ability to retain thyroglobulin mRNA on a nitrocellulose filter. The cDNA insert in pRT6 was subsequently used to screen a rat thyroid cDNA library constructed with large cDNA. A plasmid was found containing a 1700-bp insert. The polarity and the fidelity of the insert is demonstrated by S1 mapping.     

Geographic and breed distribution of an Msp I PCR-RFLP in the bovine growth hormone (bGH) gene

Information is presented on the frequency of the Msp I (-) allele in the third intron of the bovine growth hormone gene in a large number of cattle breeds. Consideration of the breed frequencies in relation to their geographic origin shows a low frequency for breeds originating in Northern Europe, moderate frequencies for breeds originating in Eastern Europe or the countries surrounding the Mediterranean basin, and very high frequencies for breeds originating in the Indian subcontinent. Consideration of breed frequencies in relation to breed type, shows low to moderate frequencies for the humpless breeds, high frequencies for the humped breeds. Various explanations for this distribution are discussed, among them the possibility that the Msp I (-) allele originated in the Bos indicus breeds of the Indian subcontinent, from which it diffused through the humpless Bos taurus breeds of Eastern Europe, the Mediterranean basin, eventually reaching Western, Northern Europe, Western Africa in low frequencies.     

Benzotriazonine as a new core structure for the design of CCK‐receptor antagonists

The search for heterocyclic scaffolds for the design of non‐peptidic and highly selective agonists or antagonists of peptide hormone receptors led to 4‐N‐benzyl‐2,3,4,5,6,7‐hexahydro‐1H‐1,4,7‐benzotriazonin‐2,6‐dione with a 9‐membered core structure as a new low mass lead compound that exhibits submicromolar antagonistic activity at the CCK‐A receptor with a 54‐fold selectivity over the CCK‐B/gastrin receptor. Copyright © 1999 European Peptide Society and John Wiley & Sons, Ltd.     

The Luteinizing Hormone Surge Regulates Circadian Clock Gene Expression in the Chicken Ovary

The molecular circadian clock mechanism is highly conserved between mammalian and avian species. Avian circadian timing is regulated at multiple oscillatory sites, including the retina, pineal, and hypothalamic suprachiasmatic nucleus (SCN). Based on the authors’ previous studies on the rat ovary, it was hypothesized that ovarian clock timing is regulated by the luteinizing hormone (LH) surge. The authors used the chicken as a model to test this hypothesis, because the timing of the endogenous LH surge is accurately predicted from the time of oviposition. Therefore, tissues can be removed before and after the LH surge, allowing one to determine the effect of LH on specific clock genes. The authors first examined the 24-h expression patterns of the avian circadian clock genes of Bmal1, Cry1, and Per2 in primary oscillatory tissues (hypothalamus and pineal) as well as peripheral tissues (liver and ovary). Second, the authors determined changes in clock gene expression after the endogenous LH surge. Clock genes were rhythmically expressed in each tissue, but LH influenced expression of these clock genes only in the ovary. The data suggest that expression of ovarian circadian clock genes may be influenced by the LH surge in vivo and directly by LH in cultured granulosa cells. LH induced rhythmic expression of Per1 and Bmal1 in arrhythmic, cultured granulosa cells. Furthermore, LH altered the phase and amplitude of clock gene rhythms in serum-shocked granulosa cells. Thus, the LH surge may be a mechanistic link for communicating circadian timing information from the central pacemaker to the ovary. (Author correspondence: stischkau@siumed.edu)