Lin Wang

Anhui Agricultural University (AHAU), Luchow, Anhui Sheng, China

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Publications (6)12.15 Total impact

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    ABSTRACT: The objective of the present study was to evaluate the effects of ghrelin on the concentrations of estrogen (E(2)) and progesterone (P(4)) in serum and the mRNA expression of estrogen receptor beta (ER(β)) and progesterone receptor (PR(A+B)) in ovary in rats during estrous cycle. Adult female Sprague Dawley rats were intracerebroventricularly (i.c.v.) injected with 3 nmol ghrelin during the estrous cycle, and sacrificed 15 min later. Blood samples and ovaries were collected. The concentrations of serum E(2) and P(4) were measured by radioimmunoassay, while the amount of ER(β) and PR(A+B) mRNA was assessed by real-time quantitative PCR. Our studies showed that ghrelin could significantly reduce the serum concentration of E(2) throughout the estrous cycle (P < 0.05), the serum level of P(4) (P < 0.05), and the amount of ER(β) mRNA during metestrus (P < 0.05). Meanwhile, the amount of PR(A+B) mRNA was only reduced during diestrus (P < 0.05). Overall, our present findings provide the first evidence that i.c.v. injection of ghrelin could reduce the serum concentration of E(2) and P(4) and the level of ER(β) and PR(A+B) mRNA expression, supporting the role of ghrelin in reproduction.
    No preview · Article · Dec 2011 · Systems biology in reproductive medicine
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    ABSTRACT: The present study was designed to determine the effects of ghrelin on in vivo and in vitro secretion of testosterone (T) and the expression of androgen receptor (AR) mRNA in the adult rat testis. The distribution of growth hormone secretagogue receptors (GHS-R(1a)) in the testis was also investigated. GHS-R(1a) immunoreactivity presented mainly in Sertoli and Leydig cells, primary spermatocytes, and secondary spermatocytes. Adult rats that were intracerebroventricularly (i.c.v.) administrated different dosages (1 nmol and 3 nmol) of ghrelin could significantly inhibit the secretion of T. The experession of AR mRNA in the testis was also notably reduced with 3 nmol ghrelin. Additionaly, in vitro exposure of the Leydig cells to increasing concentrations of ghrelin resulted in no obvious changes of T secretion in the culture media and AR mRNA expression of Leydig cells. Overall, our data demonstrate that the i.c.v. injection of ghrelin plays a physiological role in T secretion and AR mRNA expression in the testis, further confirming the reproductive role of ghrelin.
    No preview · Article · Feb 2011 · Systems biology in reproductive medicine
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    ABSTRACT: A recombinant fusion protein, maltose-binding protein (MBP)--gonadotropin releasing hormone I (GnRH-I), was produced by cloning a gene fragment encoding a tandem repeated GnRH-I hexamer peptide (GnRH-I6) into the pMAL-c4x vector which was subsequently expressed in E. coli TB1. MBP-GnRH-I6 was affinity purified. MBP-GnRH-I6 was verified by SDS-PAGE and Western blot and immunogenicity tested in boars. Injection of the recombinant fusion protein into boars yielded a high-titer antibody specific for GnRH-I. This was followed by serum testosterone and the degeneration of spermatogenesis. These results showed that MBP-GnRH-I6 acted as a strong immunogen and could be a candidate for an immune antifertility vaccine.
    No preview · Article · Dec 2010 · Systems biology in reproductive medicine
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    ABSTRACT: Immunization using recombinant maltose binding protein-gonadotropin releasing hormone (MBP-GnRH6) altered both testicular development and transcription of the pituitary GnRH receptor (GnRHR) gene in boars. Scrotal measurement and blood samples were taken at 4-week interval after immunization at 9 weeks of age. The concentrations of testosterone and anti-GnRH antibodies in serum were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. The results showed that active immunization with MBP-GnRH6 increased the serum concentration of anti-GnRH antibodies (P<0.05) and reduced the serum concentration of testosterone (P<0.05) as compared with MBP controls. At 25 weeks of age, boars were sacrificed and testes were evaluated histologically. Testicular development was suppressed in the MBP-GnRH6 immunized animals as compared with MBP immunized boars. MBP-GnRH6 immunized pigs exhibited mounting behavior 4 weeks later than MBP immunized boars. No mature spermatozoa were observed from MBP-GnRH6 immunized animals. By real-time quantitative PCR analysis, the amount of GnRHR mRNA in the pituitary tissue was found to be significantly lower in MBP-GnRH6 immunized animals than in controls (P<0.05). These data demonstrate that recombinant MBP-GnRH6 was effective in immunological castration in boars.
    No preview · Article · Jun 2010 · Animal reproduction science
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    Haidong Li · Lin Wang · Yisong Zheng
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    ABSTRACT: The linear conductance spectrum of a metallic graphene junction formed by interconnecting two gapless graphene nanoribbons is calculated. A strong conductance suppression appears in the vicinity of the Dirac point. We found that such a conductance suppression arises from the antiresonance effect associated with an edge state localized at the zigzag-edged shoulder of the junction. The conductance valley due to the antiresonance is rather robust in the presence of the impurity and vacancy scattering. Also the center of the conductance valley can be readily tuned by an electric field exerted on the wider nanoribbon.
    Preview · Article · Feb 2009 · Journal of Applied Physics
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    Haidong Li · Lin Wang · Zhihuan Lan · Yisong Zheng
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    ABSTRACT: In the effective mass approximation, electronic property in graphene can be characterized by the relativistic Dirac equation. Within such a continuum model we investigate the electronic transport through graphene waveguides formed by connecting multiple segments of armchair-edged graphene nanoribbons of different widths. By using appropriate wavefunction connection conditions at the junction interfaces, we generalize the conventional transfer matrix approach to formulate the linear conductance of the graphene waveguide in terms of the structure parameters and the incident electron energy. In comparison with the tight-binding calculation, we find that the generalized transfer matrix method works well in calculating the conductance spectrum of a graphene waveguide even with a complicated structure and relatively large size. The calculated conductance spectrum indicates that the graphene waveguide exhibits a well-defined insulating band around the Dirac point, even though all the constituent ribbon segments are gapless. We attribute the occurrence of the insulating band to the antiresonance effect which is intimately associated with the edge states localized at the shoulder regions of the junctions. Furthermore, such an insulating band can be sensitively shifted by a gate voltage, which suggests a device application of the graphene waveguide as an electric nanoswitch.
    Preview · Article · Dec 2008 · Physical review. B, Condensed matter