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Lihu Yang

Bio: Lihu Yang is an academic researcher from Merck & Co.. The author has contributed to research in topics: Chemokine receptor & Growth hormone secretion. The author has an hindex of 32, co-authored 139 publications receiving 3964 citations.


Papers
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Journal ArticleDOI
23 Oct 1998-Science
TL;DR: The availability of high-affinity, subtype-selective agonists for each of the somatostatin receptors provides a direct approach to defining their physiological functions, including inhibition of glucagon release from mouse pancreatic alpha cells and mediator of insulin secretion from pancreatic beta cells.
Abstract: Nonpeptide agonists of each of the five somatostatin receptors were identified in combinatorial libraries constructed on the basis of molecular modeling of known peptide agonists. In vitro experiments using these selective compounds demonstrated the role of the somatostatin subtype-2 receptor in inhibition of glucagon release from mouse pancreatic alpha cells and the somatostatin subtype-5 receptor as a mediator of insulin secretion from pancreatic beta cells. Both receptors regulated growth hormone release from the rat anterior pituitary gland. The availability of high-affinity, subtype-selective agonists for each of the somatostatin receptors provides a direct approach to defining their physiological functions.

446 citations

Journal ArticleDOI
Songnian Lin1, Lihu Yang1
TL;DR: In this paper, a direct one-step synthesis of various benzimidazoles from phenylenediamines and aldehydes using air as the oxidant is described.

190 citations

Journal ArticleDOI
01 Aug 2008-Diabetes
TL;DR: GPR40 does not mediate the chronic toxic effects of FFAs on islet function, and pharmacological activation of GPR40 may potentiate GDIS in humans and be beneficial for overall glucose control in patients with type 2 diabetes.
Abstract: OBJECTIVE— Acute activation of G protein–coupled receptor 40 (GPR40) by free fatty acids (FFAs) or synthetic GPR40 agonists enhances insulin secretion. However, it is still a matter of debate whether activation of GPR40 would be beneficial for the treatment of type 2 diabetes, since chronic exposure to FFAs impairs islet function. We sought to evaluate the specific role of GPR40 in islets and its potential as a therapeutic target using compounds that specifically activate GPR40. RESEARCH DESIGN AND METHODS— We developed a series of GPR40-selective small-molecule agonists and studied their acute and chronic effects on glucose-dependent insulin secretion (GDIS) in isolated islets, as well as effects on blood glucose levels during intraperitoneal glucose tolerance tests in wild-type and GPR40 knockout mice (GPR40 −/− ). RESULTS— Small-molecule GPR40 agonists significantly enhanced GDIS in isolated islets and improved glucose tolerance in wild-type mice but not in GPR40 −/− mice. While a 72-h exposure to FFAs in tissue culture significantly impaired GDIS in islets from both wild-type and GPR40 −/− mice, similar exposure to the GPR40 agonist did not impair GDIS in islets from wild-type mice. Furthermore, the GPR40 agonist enhanced insulin secretion in perfused pancreata from neonatal streptozotocin-induced diabetic rats and improved glucose levels in mice with high-fat diet–induced obesity acutely and chronically. CONCLUSIONS— GPR40 does not mediate the chronic toxic effects of FFAs on islet function. Pharmacological activation of GPR40 may potentiate GDIS in humans and be beneficial for overall glucose control in patients with type 2 diabetes.

172 citations

Journal ArticleDOI
TL;DR: The high potency and selectivity of L-054, 522 for sst2 will make it a useful tool to further characterize the physiological functions of this receptor subtype.
Abstract: A series of nonpeptide somatostatin agonists which bind selectively and with high affinity to somatostatin receptor subtype 2 (sst2) have been synthesized. One of these compounds, L-054,522, binds to human sst2 with an apparent dissociation constant of 0.01 nM and at least 3,000-fold selectivity when evaluated against the other somatostatin receptors. L-054,522 is a full agonist based on its inhibition of forskolin-stimulated adenylate cyclase activity in Chinese hamster ovary-K1 cells stably expressing sst2. L-054,522 has a potent inhibitory effect on growth hormone release from rat primary pituitary cells and glucagon release from isolated mouse pancreatic islets. Intravenous infusion of L-054,522 to rats at 50 μg/kg per hr causes a rapid and sustained reduction in growth hormone to basal levels. The high potency and selectivity of L-054,522 for sst2 will make it a useful tool to further characterize the physiological functions of this receptor subtype.

133 citations

Patent
15 Nov 1993
TL;DR: In this article, the authors have disclosed certain novel compounds identified as spiro piperidines and homologs which promote the release of growth hormone in humans and animals, which can be utilized to promote the growth of food animals to render the production of edible meat products more efficient.
Abstract: There are disclosed certain novel compounds identified as spiro piperidines and homologs which promote the release of growth hormone in humans and animals. This property can be utilized to promote the growth of food animals to render the production of edible meat products more efficient, and in humans, to treat physiological or medical conditions characterized by a deficiency in growth hormone secretion, such as short stature in growth hormone deficient children, and to treat medical conditions which are improved by the anabolic effects of growth hormone. Growth hormone releasing compositions containing such spiro compounds as the active ingredient thereof are also disclosed.

125 citations


Cited by
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Journal ArticleDOI
TL;DR: The discovery of ghrelin indicates that the release of GH from the pituitary might be regulated not only by hypothalamic GH-releasing hormone, but also by gh Relin derived from the stomach, which plays important roles for maintaining GH release and energy homeostasis in vertebrates.
Abstract: Small synthetic molecules called growth hormone secretagogues (GHSs) stimulate the release of growth hormone (GH) from the pituitary. They act through the GHS-R, a G protein-coupled receptor whose ligand has only been discovered recently. Using a reverse pharmacology paradigm with a stable cell line expressing GHS-R, we purified an endogenous ligand for GHS-R from rat stomach and named it "ghrelin," after a word root ("ghre") in Proto-Indo-European languages meaning "grow." Ghrelin is a peptide hormone in which the third amino acid, usually a serine but in some species a threonine, is modified by a fatty acid; this modification is essential for ghrelin's activity. The discovery of ghrelin indicates that the release of GH from the pituitary might be regulated not only by hypothalamic GH-releasing hormone, but also by ghrelin derived from the stomach. In addition, ghrelin stimulates appetite by acting on the hypothalamic arcuate nucleus, a region known to control food intake. Ghrelin is orexigenic; it is secreted from the stomach and circulates in the bloodstream under fasting conditions, indicating that it transmits a hunger signal from the periphery to the central nervous system. Taking into account all these activities, ghrelin plays important roles for maintaining GH release and energy homeostasis in vertebrates.

2,740 citations

Journal ArticleDOI
TL;DR: Privileged substructures are believed to achieve this through the mimicry of common protein surface elements that are responsible for binding, such as β- and gamma;-turns.
Abstract: Privileged substructures are of potentially great importance in medicinal chemistry. These scaffolds are characterized by their ability to promiscuously bind to a multitude of receptors through a variety of favorable characteristics. This may include presentation of their substituents in a spatially defined manner and perhaps also the ability to directly bind to the receptor itself, as well as exhibiting promising characteristics to aid bioavailability of the overall molecule. It is believed that some privileged substructures achieve this through the mimicry of common protein surface elements that are responsible for binding, such as β- and gamma;-turns. As a result, these structures represent a promising means by which new lead compounds may be identified.

2,620 citations

Journal ArticleDOI
TL;DR: The purpose of this review is to provide a comprehensive survey of the current understanding of prolactin's function and its regulation and to expose some of the controversies still existing.
Abstract: Prolactin is a protein hormone of the anterior pituitary gland that was originally named for its ability to promote lactation in response to the suckling stimulus of hungry young mammals. We now know that prolactin is not as simple as originally described. Indeed, chemically, prolactin appears in a multiplicity of posttranslational forms ranging from size variants to chemical modifications such as phosphorylation or glycosylation. It is not only synthesized in the pituitary gland, as originally described, but also within the central nervous system, the immune system, the uterus and its associated tissues of conception, and even the mammary gland itself. Moreover, its biological actions are not limited solely to reproduction because it has been shown to control a variety of behaviors and even play a role in homeostasis. Prolactin-releasing stimuli not only include the nursing stimulus, but light, audition, olfaction, and stress can serve a stimulatory role. Finally, although it is well known that dopamine of hypothalamic origin provides inhibitory control over the secretion of prolactin, other factors within the brain, pituitary gland, and peripheral organs have been shown to inhibit or stimulate prolactin secretion as well. It is the purpose of this review to provide a comprehensive survey of our current understanding of prolactin's function and its regulation and to expose some of the controversies still existing.

2,193 citations

Journal ArticleDOI
TL;DR: An overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present is provided.
Abstract: Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

1,709 citations

Journal ArticleDOI
TL;DR: Among the wide spectrum of SST effects, several biological responses have been identified that display absolute or relative subtype selectivity and selected nonpeptide agonists with nanomolar affinity have been developed.

1,557 citations