A capillary electrophoresis method is proposed to analyze the four most well-known growth hormone-releasing hormone (GHRH) analogs that are misused by athletes. Dimethyl-β-cyclodextrin used as a chiral selector allowed, for the first time, the separation of those basic peptide analogs, including enantiopeptides (sermorelin and CJC-1293) that differ by the chirality of only one amino acid. To increase the method sensitivity, electrokinetic preconcentration methods have been investigated. The large volume sample stacking with polarity switching (PS-LVSS) method with an injected sample volume corresponding to 80% of the capillary one was found superior to the sweeping in terms of signal enhancement factor (SEF). Acid and organic solvent addition to the sample (0.1 mM phosphoric acid with 30% methanol) led to a twofold signal improvement, when compared to water as a matrix. We increased capillary dimensions to provide a signal enhancement through the injection of a larger sample volume. Finally, using a combination of the optimized PS-LVSS preconcentration with the chiral capillary zone electrophoresis (CZE), the GHRH analogs were separated and limits of detection between 75 and 200 ng/mL were reached. This method was successfully applied to urine after a desalting step. An optimized C18 SPE was used for that purpose in order to provide low sample conductivity (<130 µS/cm) and preserve the efficiency of LVSS preconcentration. SEF of 640 was obtained with desalted urine spiked with sermorelin by comparison to the CZE (without preconcentration) method.
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http://dx.doi.org/10.1002/elps.202200278 | DOI Listing |
Rev Endocr Metab Disord
January 2025
Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Biomedical Research Building, 1501 N.W. 10th Avenue, Room 908, Miami, FL, 33136, USA.
Growth hormone (GH)-releasing hormone (GHRH), a hypothalamic peptide initially characterized for its role in GH regulation, has gained increasing attention due to its GH-independent action on peripheral physiology, including that of the cardiovascular system. While its effects on the peripheral vasculature are still under investigation, GHRH and synthetic agonists have exhibited remarkable receptor-mediated cardioprotective properties in preclinical models. GHRH and its analogs enhance myocardial function by improving contractility, reducing oxidative stress, inflammation, and offsetting pathological remodeling.
View Article and Find Full Text PDFRev Endocr Metab Disord
January 2025
Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Illinois at Chicago, Chicago, IL, USA.
This review focuses on our current understanding of how growth hormone releasing hormone (GHRH): 1) stimulates GH release and synthesis from pituitary growth hormone (GH)-producing cells (somatotropes), 2) drives somatotrope proliferation, 3) is negatively regulated by somatostatin (SST), GH and IGF1, 4) is altered throughout lifespan and in response to metabolic challenges, and 5) analogues can be used clinically to treat conditions of GH excess or deficiency. Although a large body of early work provides an underpinning for our current understanding of GHRH, this review specifically highlights more recent work that was made possible by state-of-the-art analytical tools, receptor-specific agonists and antagonists, high-resolution in vivo and ex vivo imaging and the development of tissue (cell) -specific ablation mouse models, to paint a more detailed picture of the regulation and actions of GHRH.
View Article and Find Full Text PDFNeuro Endocrinol Lett
December 2024
Di Bella Foundation, Via Guglielmo Marconi 51 Bologna, 40122 Italy.
Objectives: Triple negative breast cancer (TNBC) is a distinct subtype of breast cancer that has a poor prognosis due to the lack of effective therapeutic agents. Since a significant proportion of human surgical samples of TNBC expressed mRNA for the growth hormone (GH), growth hormone-releasing hormone (GHRH), and gonadotropin-releasing hormone (GnRH) receptors, and the mitogenic proliferative activity of GH, GHRH, and GnRH, have been identified as effective therapeutic targets for somatostatin and its analogs and GnRH analogs, Di Bella Method (DBM), a combination of hormonal analogs and vitamins, was introduced to target and inhibit solid tumors. The present study aimed to improve the prognosis of TNBC using DBM in women with TNBC.
View Article and Find Full Text PDFRev Endocr Metab Disord
November 2024
Miami VA Healthcare System, Endocrine and Polypeptide Institute, Miami, FL, USA.
Growth Hormone-Releasing Hormone (GHRH) and its analogs have gained significant attention for their therapeutic potential across various domains, including oncology, regenerative medicine, and metabolic disorders. Originally recognized for its role in regulating growth hormone (GH) secretion, GHRH has since been discovered to exert broader physiological effects beyond the pituitary gland, with GHRH receptors identified in multiple extrahypothalamic tissues, including tumor cells. This review explores the development of both GHRH agonists and antagonists, focusing on their mechanisms of action, therapeutic applications, and future potential.
View Article and Find Full Text PDFRev Endocr Metab Disord
November 2024
Department of Cardiology of The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China.
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