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Reproduction in Domestic Animals =... Jul 2020Dog reproductive cycle is unique among other mammals in that females experience long and variable periods of ovarian inactivity. Neuroendocrine controls of the... (Review)
Review
Dog reproductive cycle is unique among other mammals in that females experience long and variable periods of ovarian inactivity. Neuroendocrine controls of the reproductive cycle have been thoroughly studied in the dog. However, there is little information regarding endocrine, paracrine and autocrine controls of dog ovarian folliculogenesis. Advancements in the understanding of mechanisms regulating dog ovarian follicle development will be helpful in the establishment of an approach to control cyclicity in this species. Furthermore, such information will likely be useful for the establishment of an in vitro follicle culture system to preserve fertility of genetically valuable disease models or endangered canids. This review highlights current knowledge on dog folliculogenesis with emphasis on endocrine, paracrine and autocrine controls of follicular development.
Topics: Animals; Autocrine Communication; Dogs; Endocrine Glands; Female; Ovarian Follicle; Paracrine Communication; Reproduction
PubMed: 32347633
DOI: 10.1111/rda.13657 -
Annual Review of Physiology 2016Homeostatic systems mount adaptive responses to meet the energy demands of the cell and to compensate for dysfunction in cellular compartments. Such surveillance systems... (Review)
Review
Homeostatic systems mount adaptive responses to meet the energy demands of the cell and to compensate for dysfunction in cellular compartments. Such surveillance systems are also active at the organismal level: Nutrient and stress sensing in one tissue can lead to changes in other tissues. Here, we review the emerging understanding of the role of skeletal muscle in regulating physiological homeostasis and disease progression in other tissues. Muscle-specific genetic interventions can induce systemic effects indirectly, via changes in the mass and metabolic demand of muscle, and directly, via the release of muscle-derived cytokines (myokines) and metabolites (myometabolites) in response to nutrients and stress. In turn, myokines and myometabolites signal to various target tissues in an autocrine, paracrine, and endocrine manner, thereby determining organismal resilience to aging, disease, and environmental challenges. We propose that tailoring muscle systemic signaling by modulating myokine and myometabolite levels may combat many degenerative diseases and delay aging.
Topics: Animals; Cytokines; Endocrine System; Food; Humans; Muscle, Skeletal; Signal Transduction; Stress, Physiological
PubMed: 26527185
DOI: 10.1146/annurev-physiol-021115-105305 -
Reproductive Sciences (Thousand Oaks,... Dec 2007Gonadotropin-releasing hormone (GnRH) plays a pivotal role in the physiology of reproduction in mammals. GnRH acts by binding to the GnRH receptor (GnRHR). In humans,... (Review)
Review
Gonadotropin-releasing hormone (GnRH) plays a pivotal role in the physiology of reproduction in mammals. GnRH acts by binding to the GnRH receptor (GnRHR). In humans, only 1 conventional GnRH receptor subtype (type I GnRH receptor) has been found. In the human genome, 2 forms of GnRH have been identified, GnRH-I (mammal GnRH) and GnRH-II (chicken GnRH II). Both forms and their common receptor are expressed, apart from the hypothalamus, in various compartments of the human ovary. Gonadal steroids, gonadotropins, and GnRH itself controls the regulation of the GnRH/GnRHR system gene expression in the human ovary. The 2 types of GnRH acting paracrinally/autocrinally influence ovarian steroidogenesis, decrease the proliferation, and induce apoptosis of ovarian cells. In this review, the biology of GnRH/GnRHR system in humans, the potential roles of GnRH, and the direct effects of GnRH analogues in ovarian cells are discussed.
Topics: Animals; Female; Gonadotropin-Releasing Hormone; Humans; Ovary; Protein Isoforms; Receptors, LHRH
PubMed: 18089592
DOI: 10.1177/1933719107310707 -
Annals of the New York Academy of... 1992As suggested by this and previous reviews, the neuroimmunoregulation of intestinal secretion is a complex series of endocrine, neurocrine, paracrine and autocrine... (Review)
Review
As suggested by this and previous reviews, the neuroimmunoregulation of intestinal secretion is a complex series of endocrine, neurocrine, paracrine and autocrine interactions between the underlying cells in the mucosa and submucosa and the intestinal enterocyte. Under normal conditions, the balance of each of these systems is delicately controlled, thus allowing for normal, consistent intestinal function. However, when this finely-tuned system is altered, such as in a diseased state, the resultant effect is an amplification of the host defense response. Initially thought to be protective against further insult, this local immune response, if allowed to continue uncontrollably, can exacerbate the disease process.
Topics: Animals; Arachidonic Acid; Bradykinin; Cytokines; Histamine; Humans; Inflammatory Bowel Diseases; Intestinal Mucosa; Intestines; Serotonin
PubMed: 1456652
DOI: 10.1111/j.1749-6632.1992.tb39762.x -
Annals of the New York Academy of... Jun 2003The melanocortin peptides and their receptors represent one of the most complex systems in human endocrinology. Hormonal regulation includes pigmentation, weight... (Review)
Review
The melanocortin peptides and their receptors represent one of the most complex systems in human endocrinology. Hormonal regulation includes pigmentation, weight maintenance, adrenal function, and exocrine gland secretion via endocrine, paracrine, autocrine, and neurocrine action of melanocortin peptides at five different but homologous melanocortin receptors. Genetic relevance of the melanocortin system for human physiology was initially shown by mutations in the different melanocortin receptor genes, first described in the melanocortin-2 receptor gene in 1993 as one reason for congenital hypocortisolism. Because all ligands within the melanocortin systems are derived from one single precursor hormone, proopiomelanocortin (POMC), a genetic defect in the POMC gene could have been expected to affect all functional components of the melanocortin system. Accordingly, patients with a complete defect of the POMC gene product due to homozygous or compound heterozygous loss of function mutations were shown to be affected mainly by red hair, early-onset obesity, and congenital hypocortisolism. No further obvious clinical problems were described in these patients, suggesting that no additional function of the melanocortin system has escaped recognition. However, whether partial loss of function mutations in the POMC gene might lead to more circumscribed phenotypes, especially common obesity, remains an open question.
Topics: Animals; Genetic Testing; Humans; Mutation; Obesity; Peptides; Phenotype; Polymorphism, Genetic; Pro-Opiomelanocortin
PubMed: 12851321
DOI: 10.1111/j.1749-6632.2003.tb03185.x -
Biophysical Journal Feb 2003Intracellular signaling induced by peptide growth factors can stimulate secretion of these molecules into the extracellular medium. In autocrine and paracrine networks,... (Comparative Study)
Comparative Study
Intracellular signaling induced by peptide growth factors can stimulate secretion of these molecules into the extracellular medium. In autocrine and paracrine networks, this can establish a positive feedback loop between ligand binding and ligand release. When coupled to intercellular communication by autocrine ligands, this positive feedback can generate constant-speed traveling waves. To demonstrate that, we propose a mechanistic model of autocrine relay systems. The model is relevant to the physiology of epithelial layers and to a number of in vitro experimental formats. Using asymptotic and numerical tools, we find that traveling waves in autocrine relays exist and have a number of unusual properties, such as an optimal ligand binding strength necessary for the maximal speed of propagation. We compare our results to recent observations of autocrine and paracrine systems and discuss the steps toward experimental tests of our predictions.
Topics: Autocrine Communication; Biological Transport; Cell Communication; Computer Simulation; Diffusion; Epithelium; Feedback, Physiological; Hormones; Ligands; Models, Biological; Models, Chemical; Protein Binding; Receptors, Cell Surface
PubMed: 12547771
DOI: 10.1016/S0006-3495(03)74906-6 -
The International Journal of... 2000Development of the nervous system is dependent on the co-operation between cell determination events and the action of epigenetic factors; in addition to well known... (Review)
Review
Development of the nervous system is dependent on the co-operation between cell determination events and the action of epigenetic factors; in addition to well known factors, e.g. growth factors, neurotransmitters have been assigned a role as "morphogens" and modulators of neuronal differentiation in an early developmental phase. The possible role of acetylcholine as a modulator of neuronal differentiation has been considered in two experimental systems. A neuroblastoma cell line, which does not synthesise any neurotransmitter, has been transfected with a choline acetyltransferase construct; activation of acetylcholine synthesis, thus achieved, is followed by a higher expression of neuronal specific traits. The presence in these cells of muscarinic receptors is consistent with the existence of an autocrine loop, which may be responsible for the more advanced differentiation state observed in the transfected cells. Expression of cholinergic markers appears as a common feature of DRG sensory neurons, independently of the neurotransmitter used. Choline acetyltransferase can be detected in DRG at early developmental stages. The distribution of muscarinic receptors in DRG has suggested that activation of acetylcholine synthesis may be related in an early developmental phase to the interaction between neurons and nonneuronal cells and to modulation of cell differentiation. Both systems suggest that acetylcholine may have a role as a modulator of neuronal differentiation.
Topics: Acetylcholine; Animals; Blotting, Northern; Cell Differentiation; Choline O-Acetyltransferase; Ganglia, Spinal; Humans; Immunohistochemistry; Mice; Nervous System; Neuroblastoma; Neurons; Neurons, Afferent; Receptors, Muscarinic; Transfection; Tumor Cells, Cultured
PubMed: 11061433
DOI: No ID Found -
Proceedings of the Society For... Jan 1996NO and cGMP constitute an autocrine, paracrine, and possible endocrine signal transduction system. Cytosolic NO-responsive guanylyl cyclase can be stimulated by NO... (Review)
Review
NO and cGMP constitute an autocrine, paracrine, and possible endocrine signal transduction system. Cytosolic NO-responsive guanylyl cyclase can be stimulated by NO derived from its own cell, from similar or distinct neighboring cell types within a tissue, from a circulating pool of NO (as NO+ equivalents coupled to plasma protein thiol groups), or from pharmacologic agents, the nitrovasodilators. NO and cGMP together comprise an especially wide-ranging signal transduction system when one considers (i) the many roles of cGMP in physiological regulation, including smooth muscle relaxation, visual transduction, intestinal ion transport, and platelet function; (ii) the many sources, biochemical interactions, and functions of NO; and (iii) the interactions of cGMP and its affected pathways with other signaling systems such as phosphoinositides, eicosanoids, cAMP and Ca2+.
Topics: Animals; Cyclic GMP; Guanylate Cyclase; Humans; Nitric Oxide; Nitric Oxide Synthase; Phosphatidylinositols
PubMed: 8594612
DOI: 10.3181/00379727-211-43950a -
European Journal of Pharmacology Aug 2015The review describes DAA-I (des-aspartate-angiotensin-I) as a prototype of a novel class of drugs that acts as agonists on the angiotensin AT1 receptor or ARAs... (Review)
Review
The review describes DAA-I (des-aspartate-angiotensin-I) as a prototype of a novel class of drugs that acts as agonists on the angiotensin AT1 receptor or ARAs (angiotensin receptor agonists). DAA-I is a component of the renin angiotensin system. Earlier studies showed that it was rapidly metabolized to angiotensin III. However, when administered at doses below the Km of enzymes, DAA-I produces specific actions that antagonize the deleterious actions of angiotensin II. DAA-I exerts protective actions in animal models of eight human pathologies in which angiotensin II is implicated. The pathologies include cardiac hypertrophy, neointima growth and cardiovascular hypertrophy, myocardial-ischemia reperfusion injury, hyperglycemia and insulin resistance, chemical induced inflammation, and exercise-induced skeletal muscle inflammation. Binding of DAA-I to the angiotensin AT1 receptors releases prostaglandins, which could either function as autocrines/paracrines or second messengers and attenuate the deleterious actions of angiotensin II. It is possible that in in vivo DAA-I functions as a physiological antagonist to angiotensin II, and exogenous DAA-I is a novel class of angiotensin receptor drug that could rival the angiotensin receptor blockers.
Topics: Angiotensin I; Animals; Blood Pressure; Cardiomegaly; Humans; Hyperglycemia; Myocardial Reperfusion Injury; Receptor, Angiotensin, Type 1
PubMed: 25891368
DOI: 10.1016/j.ejphar.2015.04.004 -
Annual Review of Physiology 1993The recent availability of reagents to study the IGFs, their receptors, and binding proteins has led to an explosive growth in the study of IGF physiology. However, most... (Review)
Review
The recent availability of reagents to study the IGFs, their receptors, and binding proteins has led to an explosive growth in the study of IGF physiology. However, most studies to date have been descriptive, and studies delineating mechanisms of action are limited. It is apparent that most organ systems synthesize several components of the IGF system necessary for IGF to function in an autocrine or paracrine fashion and that regulation of this system occurs at the local level. However, the relative importance of locally produced IGF vs circulating IGF remains unclear. The mechanisms by which the IGFBPs modulate IGF activity are crucial to understanding this system, and identification of specific roles for each of these proteins will be required. Of critical importance is the identity of the intracellular signal transduction system by which the IGF receptor mediates the effects of the IGFs, and the delineation of mechanisms by which the IGFBPs interact with the receptor at the cellular level. It is also of interest to determine what role, if any, the IGF-II receptor plays in mediating the growth-promoting effects of the IGFs. The ubiquitous distribution of the IGFs, IGFBPs, and IGF receptors indicates that they may play a role in the regulation of coordinate growth among several tissues and cell types. Understanding the mechanisms by which these components interact to coordinate growth responses between different cell types should greatly enhance our understanding of normal growth and development.
Topics: Animals; Humans; Receptor, IGF Type 2; Somatomedins
PubMed: 8466170
DOI: 10.1146/annurev.ph.55.030193.001023