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General Aspects of Endocrine Physiology
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The peptide hormones are synthesized by mRNA transcription in the nucleus, leading to ribosomal translation with the production of the polypeptide within the endoplasmic reticulum. The polypeptide is concentrated in the Golgi apparatus and then stored in storage granules. Large protein hormones are usually retained in the storage granules, whereas small peptide hormones are bound to specific binding proteins within the granules (Figure 59.1). The hormones are released from the endocrine cell by exocytosis following a neural, chemical, hormonal or physical stimulus. Hormones not released are usually degraded to amino acids and recycled.
Effects of Stress on Physiological Conditions in the Oral Cavity
Published in Eli Ilana, Oral Psychophysiology, 2020
Recently, newly-discovered neuropharmacological substances have been reported as possible mediators of the interrelationship between stress and periodontal disease.87 Apparently, peptide hormones, such as substance P and bombesin affect not only the neurological system but also such behavior as drinking, eating, sexual drive, pain, and pleasure.88 These aspects of mood can, therefore, influence behaviors such as diet (nutrition) or change in oral hygiene habits. Peptide hormones can also induce changes in lymphocyte cells which lead to the production of other hormones (i.e., growth hormones) and vasoactive intestine peptides. As lymphocytes are a common inflammatory cell of the periodontium, mood can presumably affect the periodontal condition in this manner.87
The endocrine system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
The protein/peptide hormones are derived from amino acids and most hormones are of this type. Peptide hormones contain fewer than 100 amino acids (e.g., antidiuretic hormone, oxytocin, insulin, and glucagon). Protein hormones contain more than 100 amino acids (e.g., growth hormone). Glycoprotein hormones are peptide chains containing more than 100 amino acids as well as one or more carbohydrate groups (e.g., follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone).
Subcutaneous catabolism of peptide therapeutics: bioanalytical approaches and ADME considerations
Published in Xenobiotica, 2022
Simone Esposito, Laura Orsatti, Vincenzo Pucci
Therapeutic peptides represent a unique niche that occupies a well-established chemical space between small molecules and large biologics. Peptide-based drugs account for a small yet relevant portion of the pharmaceutical market, with worldwide sales of more than $70 billion in 2019 and further growth expected in the coming years (Muttenthaler et al. 2021). Therapeutic peptides drug discovery started in the early twentieth century with natural human hormones like insulin and gonadotropin-releasing hormone. However, the identification of other peptide hormones with potential therapeutic properties and the significant technological innovations in the fields of synthesis, analysis, and purification of recombinant biologics and in structural biology have considerably accelerated the development of therapeutic peptide drugs. Notably, over 60 peptides have been approved in the last two decades in the United States, Europe and Japan, and more than 150 are currently undergoing clinical trials, covering a wide range of therapeutic areas (Wang et al. 2022). Although new indications continue to emerge, the main therapeutic areas are metabolic disease and oncology, followed by infectious disease, inflammation, cardiovascular, respiratory disease, and urology.
The role of peptide-based therapeutics in oncotherapy
Published in Journal of Drug Targeting, 2021
Selin Seda Timur, R. Neslihan Gürsoy
A significant portion of clinically approved peptides consist of peptide hormones used in cancer therapy. A typical case is Gonadotropin-releasing hormone (GnRH) agonists (i.e.buserelin and leuprolide) as well as antagonists (i.e. abarelix and cetrorelix) which are utilised in prostate cancer treatment. Another similar group is somatostatin analogs, which are used either alone or in combination with radionuclide in peptide receptor radionuclide therapy (PRRT) during cancer treatment [41]. The success of the clinically approved peptide hormones has caused several researchers to divert their focus towards the use of peptide analogs for targeted cancer therapy. In the case of Gonadotropin-releasing hormone (GnRH), a decapeptide (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) naturally produced to control reproductive functions in the body, the receptor -(LHRH receptor) is overexpressed in different cancers including breast, prostate and ovarian cancer, thus providing an opportunity for receptor mediated-tumour targeting for therapy and diagnosis [42,43]. GnRH, also known as luteinizing hormone-releasing hormone (LHRH), was utilised in cancer therapy as targeting moiety in form of conjugates with anticancer drugs, polymers, or drug delivery systems such as liposomes, dendrimers, micelles, and silica nanoparticles [42,44]. Antineoplastic agents such as doxorubicin, cisplatin, melphalan as well as imaging agents like DOTA were conjugated to GnRH to enhance conventional cancer diagnosis and therapy [42,45].
In vitro effect of DDE exposure on the regulation of B-TC-6 pancreatic beta cell insulin secretion: a potential role in beta cell dysfunction and type 2 diabetes mellitus
Published in Toxicology Mechanisms and Methods, 2021
Antonio B. Ward, Mary B. Dail, Janice E. Chambers
The in vitro effect of DDE exposure on pancreatic beta cell function was examined with respect to biochemical markers of glucose-associated insulin secretion that might suggest possible mechanisms of DDE effects in the development of T2D: insulin, pancreatic and duodenal homeobox factor-1 (PDX-1), prohormone convertase endopeptidases (PC), and reactive oxygen species (ROS). The peptide hormone, insulin, is synthesized and secreted by pancreatic beta cells in response to elevated extracellular blood glucose concentrations (Itoh et al. 2003). PDX-1 is a transcription factor present in beta cells which regulates insulin gene transcription (McKinnon and Docherty 2001). Reduced expression of PDX-1 is associated with beta cell dysfunction, hyperglycemia, and T2D (Brissova et al. 2005). PC are involved in the cleavage of insulin to its mature form and a disruption of this mechanism contributes to altered insulin secretion and beta cell dysfunction (Rhodes and Alarcón 1994). ROS are indicative of oxidative stress and play a role in beta cell dysfunction since pancreatic beta cells express low levels of antioxidants (Evans et al. 2003). In vitro DDE alteration of these biochemical markers of glucose-associated insulin synthesis and/or secretion from pancreatic beta cells would lend support to the epidemiological association of DDE exposure and T2D.