Regulation of Cell Functions
Enrique Pimentel in Handbook of Growth Factors, 2017
Hormones are defined as chemical messengers synthesized in the endocrine glands of multicellular organisms and secreted into the extracellular body fluids, which transport them to more or less distantly located target cells (hormone-responsive cells), where they can exert important regulatory actions. Upon arrival to its target cell, the hormone is recognized by and binded to a specific site, the hormone receptor. The formation of a hormone-receptor complex determines the response that is specific for both the hormone and the cell.1,2 Hormones are involved in the integrated regulation and modulation of the differentiated functions of multicellular organisms. The neural system and the endocrine system have partially overlapping and complementary functions related to the integration and coordination of complex biological processes. They constitute a functionally important integrative structure of the organism, the neuroendocrine system.
Molecular Properties of Radiotracer Receptors
Lelio G. Colombetti in Principles of Radiopharmacology, 1979
The direct isolation of receptors is a difficult and challenging enterprise in which radiotracers play an important part. Initial research in this area involved the isolation of soluble steroid hormone receptors, using tritiated steroids of high specific activity.20–22 This is required because only a very small quantity of the radiotracer will interact with the specific receptor. Hormone receptors are specific for a given tissue and also for the biologically active hormone. From these investigations, a mechanism of interaction between hormone and receptor has been proposed. The macromolecular receptor is located within the cytoplasm, and, after binding with the steroid hormone, the steroid-receptor complex is transferred to the nucleus where the ultimate action of the hormone occurs.
Regulation of Food Intake
Nathalie Bergeron, Patty W. Siri-Tarino, George A. Bray, Ronald M. Krauss in Nutrition and Cardiometabolic Health, 2017
A criterion for the physiological endocrine action of gut hormones on energy intake was proposed by Geary [26]. He suggested thatHormone secretion should be associated with changes in eating—secretory effect.Receptors should be expressed at the site of action of the relevant hormone—receptor-mediated effect.Effects on appetite should be reproduced by the parenteral administration of a hormone, similar to its endogenous effects—physiological dose–related effect.Removal of the hormone or receptor should prevent the effect on appetite, and replacement of the hormone should reinstitute the effect—removal and replacement effect.Selective, potent antagonism of the hormone should prevent the effect of endogenous hormone as well as hormone treatment—antagonistic effect.However, not all the gut hormones identified fit all these criteria.
From ligands to behavioral outcomes: understanding the role of mineralocorticoid receptors in brain function
Published in Stress, 2023
Huanqing Yang, Sowmya Narayan, Mathias V. Schmidt
Steroid hormone receptors are ligand-activated and switch from an inactive state to an active state by binding to their corresponding hormones (Torchia et al., 1998). Since MR LBD shares high homology with GR LBD, MR has two main endogenous ligands: aldosterone and cortisol in humans, or CORT in rodents (Baker et al., 2013). MR has a high affinity for cortisol (Kd = 0.5 nM), 10-fold higher than GR (Kd = 5 nM) (Meijer et al., 2018). The circulating concentration of cortisol in the blood is about 100–1000 times that of aldosterone (Syed & Qureshi, 2012). Even if only 5%-10% of cortisol is actively free, cortisol levels remain much higher than aldosterone in plasma (Cizza & Rother, 2012; Mifsud & Reul, 2018). Consequently, MR will be entirely occupied by cortisol except for when the circadian cycle of cortisol release is at its lowest point. Aldosterone has the same affinity for binding MR as cortisol, and since aldosterone dissociates from MR more slowly than cortisol, the aldosterone-MR complex is more stable and potent.
Stress, mindfulness, and the allergic patient
Published in Expert Review of Clinical Immunology, 2018
Gailen D. Marshall, Matthew T. Tull
There is compelling evidence to support the notion of physiologically significant interactions between the mind and the immune system through neuroendocrine pathways. Immune solid tissues such as spleen and lymph nodes express receptors for various neurotransmitters and hormones including catecholamines (β adrenergic), acetyl choline, substance P, and vasoactive intestinal peptide [26]. Additionally, other hormone receptors such as corticosteroid, thyroid, gonadal hormones and over a dozen others are located on various immune cells that affect their trafficking and function [27]. Additionally, multiple different cytokine receptors are found in various parts of the central nervous system (CNS), including the hypothalamus and hippocampus [28], that support a bidirectional relationships between the CNS and immune networks. Indeed, sickness behavior has been attributed in large part to cytokines in the CNS produced either locally or crossing the blood – brain barrier [29]. This may explain, at least in part, the altered cognitive abilities, soporific impact, and malaise associated with immune-based diseases such as allergy, asthma, and various other inflammatory conditions [30].
Hypothesis-driven weight of evidence evaluation indicates styrene lacks endocrine disruption potential
Published in Critical Reviews in Toxicology, 2023
In this WoE methodology, specificity is also addressed by the requirement to evaluate the pattern of the responses relevant to each MoA and to interpret patterns inconsistent with the response expected of known effectors and inhibitors as unlikely to indicate activity via that pathway. Although it is theoretically possible for an agonist or antagonist of a particular hormonal pathway to exhibit a novel pattern of endpoint responses, consistent with the “selective response modifier” concept of hormone receptor interactions, a finite number of response types have been identified for the various hormone receptor systems, each consistent with ligand-receptor affinities, potencies, and the tissue distribution of hormone receptors (see Borgert et al. 2018 and references therein). Assessment approaches that fail to appreciate this basic feature of hormonal action, such as the key characteristic approach proposed by La Merrill et al. (2020), have little utility for identifying potential endocrine disruptors.
Related Knowledge Centers
- Fatty Acid
- Peptide Hormone
- Transmembrane Protein
- Prostaglandin
- Cell Membrane
- Insulin
- Receptor
- Hormone
- Vitamin D
- Cell Surface Receptor