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Gupta D, Patterson AM, Osborne-Lawrence S, Bookout AL, Varshney S, Shankar K, Singh O, Metzger NP, Richard CP, Wyler SC, Elmquist JK, Zigman JM. Disrupting the ghrelin-growth hormone axis limits ghrelin's orexigenic but not glucoregulatory actions. Mol Metab 2021; 53:101258. [PMID: 34023483 PMCID: PMC8203846 DOI: 10.1016/j.molmet.2021.101258] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/26/2021] [Accepted: 05/14/2021] [Indexed: 12/19/2022] Open
Abstract
Objective Acyl-ghrelin regulates eating, body weight, blood glucose, and GH secretion upon binding to its receptor GHSR (growth hormone secretagogue receptor; ghrelin receptor). GHSR is distributed in several brain regions and some peripheral cell-types including pituitary somatotrophs. The objective of the current study was to determine the functional significance of acyl-ghrelin's action on GHSR-expressing somatotrophs in mediating GH secretion and several of acyl-ghrelin's metabolic actions. Methods GH-IRES-Cre mice and loxP-flanked (floxed) GHSR mice were newly developed and then crossed to one another to generate mice that lacked GHSR selectively from somatotrophs. Following validation of mice with somatotroph-selective GHSR deletion, metabolic responses of these mice and control littermates were assessed following both acute and chronic acyl-ghrelin administration, a 24-h fast, and a prolonged 60% chronic caloric restriction protocol modeling starvation. Results In mice with somatotroph-selective GHSR deletion, a single peripheral injection of acyl-ghrelin failed to induce GH secretion or increase food intake, unlike wild-type and other littermate control groups. However, the usual acute blood glucose increase in response to the acyl-ghrelin bolus was preserved. Similarly, chronic s.c. acyl-ghrelin administration to mice with somatotroph-selective GHSR deletion failed to increase plasma GH, food intake, or body weight. Physiologically elevating plasma acyl-ghrelin via a 24-h fast also failed to raise plasma GH and resulted in a limited hyperphagic response upon food reintroduction in mice with somatotroph-selective GHSR deletion, although those mice nonetheless did not exhibit an exaggerated reduction in blood glucose. Physiologically elevating plasma acyl-ghrelin via a 15-day caloric restriction protocol which provided only 40% of usual daily calories failed to raise plasma GH in mice with somatotroph-selective GHSR deletion, although those mice did not exhibit life-threatening hypoglycemia. Conclusions These results reveal that direct engagement of GHSR-expressing somatotrophs is required for a peripheral ghrelin bolus to acutely stimulate GH secretion and the actions of chronic acyl-ghrelin delivery and physiological plasma acyl-ghrelin elevations to increase plasma GH. These results also suggest that actions of acyl-ghrelin to increase food intake and body weight are reliant on direct activation of GHSRs expressed on somatotrophs. Furthermore, these results suggest that the glucoregulatory actions of acyl-ghrelin – in particular, its actions to raise blood glucose when acutely administered, prevent small blood glucose drops following a 24-h fast, and avert life-threatening hypoglycemia during an acute-on-chronic caloric restriction protocol – do not depend on GHSR expression by somatotrophs. Mice with pituitary somatotroph-selective GHSR deletion were generated. Somatotroph-expressed GHSRs mediate GH secretion and food intake after acute ghrelin. Body weight effects of chronic ghrelin infusion require somatotroph-expressed GHSRs. Somatotroph-expressed GHSRs enable GH to increase upon chronic caloric restriction. Mice lacking somatotroph GHSRs maintain euglycemia upon chronic caloric restriction.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Anna M Patterson
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Angie L Bookout
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Corine P Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Steven C Wyler
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA.
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Doostmohammadi M, Ameri A, Mohammadinejad R, Dehghannoudeh N, Banat IM, Ohadi M, Dehghannoudeh G. Hydrogels For Peptide Hormones Delivery: Therapeutic And Tissue Engineering Applications. Drug Des Devel Ther 2019; 13:3405-3418. [PMID: 31579238 PMCID: PMC6770672 DOI: 10.2147/dddt.s217211] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 09/02/2019] [Indexed: 12/13/2022] Open
Abstract
Peptides are the most abundant biological compounds in the cells that act as enzymes, hormones, structural element, and antibodies. Mostly, peptides have problems to move across the cells because of their size and poor cellular penetration. Therefore, a carrier that could transfer peptides into cells is ideal and would be effective for disease treatment. Until now, plenty of polymers, e.g., polysaccharides, polypeptides, and lipids were used in drug delivery. Hydrogels made from polysaccharides showed significant development in targeted delivery of peptide hormones because of their natural characteristics such as networks, pore sizes, sustainability, and response to external stimuli. The main aim of the present review was therefore, to gather the important usages of the hydrogels as a carrier in peptide hormone delivery and their application in tissue engineering and regenerative medicine.
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Affiliation(s)
- Mohsen Doostmohammadi
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Atefeh Ameri
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Reza Mohammadinejad
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Negar Dehghannoudeh
- Faculty of Arts and Science, University of Toronto, TorontoM5S3G3, Ontario, Canada
| | - Ibrahim M Banat
- School of Biomedical Sciences, Faculty of Life & Health Sciences, University of Ulster, ColeraineBT52 1SA, Northern Ireland, UK
| | - Mandana Ohadi
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Gholamreza Dehghannoudeh
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
- Department of Pharmaceutics, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran
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Abstract
Detection of doping with recombinant human growth hormone is one of the challenges for antidoping analysis. This review focuses on the most important relevant publications that provide insight into the laboratory measurement of human growth hormone (hGH), antibodies and standards, the isoform approach and the biomarker approach. The isoform approach monitors the changes of hGH molecular isoform composition in serum and was applied at the Olympic Games in Athens in 2004, Turin in 2006 and Beijing in 2008. The markers approach detects a formula score, which reflects the changes in concentration of IGF-1 and P-III-P. All these methodologies measure the concentrations of growth hormone and its isoforms for isoform approach, or the concentrations of IGF-1 and P-III-P. All factors that affect these measurements should be taken into account for the development of methods to detect doping with recombinant hGH.
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Abstract
There is widespread anecdotal evidence that growth hormone (GH) is used by athletes for its anabolic and lipolytic properties. Although there is little evidence that GH improves performance in young healthy adults, randomized controlled studies carried out so far are inadequately designed to demonstrate this, not least because GH is often abused in combination with anabolic steroids and insulin. Some of the anabolic actions of GH are mediated through the generation of insulin-like growth factor-I (IGF-I), and it is believed that this is also being abused. Athletes are exposing themselves to potential harm by self-administering large doses of GH, IGF-I and insulin. The effects of excess GH are exemplified by acromegaly. IGF-I may mediate and cause some of these changes, but in addition, IGF-I may lead to profound hypoglycaemia, as indeed can insulin. Although GH is on the World Anti-doping Agency list of banned substances, the detection of abuse with GH is challenging. Two approaches have been developed to detect GH abuse. The first is based on an assessment of the effect of exogenous recombinant human GH on pituitary GH isoforms and the second is based on the measurement of markers of GH action. As a result, GH abuse can be detected with reasonable sensitivity and specificity. Testing for IGF-I and insulin is in its infancy, but the measurement of markers of GH action may also detect IGF-I usage, while urine mass spectroscopy has begun to identify the use of insulin analogues.
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Weltman A, Weltman JY, Roy CP, Wideman L, Patrie J, Evans WS, Veldhuis JD. Growth hormone response to graded exercise intensities is attenuated and the gender difference abolished in older adults. J Appl Physiol (1985) 2005; 100:1623-9. [PMID: 16384836 DOI: 10.1152/japplphysiol.01312.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the joint impact of age, gender, and exercise intensity on growth hormone (GH) secretion. At a university center, nine young men, eight young women, seven older men, and six older women were each tested on six randomly ordered occasions [control (C) and 5 exercise conditions (Ex)]. Serum GH concentrations were measured by immunochemiluminometry [10-min samples: 0700-0900 (baseline); 0900-1300 (C or Ex + recovery)]. Integrated GH concentrations (IGHC) were calculated by trapezoidal reconstruction, and GH secretion was modeled by deconvolution analyses. Subjects exercised from 0900 to 0930 at graded intensities [standardized to individual lactate threshold (LT)] of 25 and 75% of the difference between rest and LT, LT, and 25 and 75% of the difference between LT and peak oxygen consumption. Data were analyzed via mixed-effects ANOVA for repeated measures with post hoc contrasts. We found that 1) Ex elevated IGHC above C in all four cohorts, 2) 1.75 LT Ex resulted in maximal IGHC, 3) IGHC differed by gender in young (women > men) but not older adults, 4) older adults secreted 50% less GH during graded exercise, 5) Ex selectively augmented the mass of GH secreted per burst, and 6) higher Ex + recovery IGHC in young women was due to higher baseline IGHC, rather than greater stimulated GH secretion. We conclude that young women manifest a greater absolute and incremental IGHC response to exercise than postmenopausal women and men of any age. Age diminishes the GH response to exercise and abolishes the young-adult gender difference. Attenuation of GH responses to all exercise intensities in older adults has implications for exercise prescription because higher exercise intensities may be required to stimulate GH release in older adults.
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Affiliation(s)
- Arthur Weltman
- Department of Human Services, University of Virginia, Charlottesville, VA 22904, USA.
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Abstract
Puberty is a period of dramatic physiologic changes when children become adults. Chronic kidney disease (CKD), like many disorders, may delay or blunt the onset and outcomes of puberty. These include attainment of adult height and reproductive capacity. Although nutrition and treatment effects may contribute to these phenomena, increasing evidence supports direct biological effects of CKD on the neurohypophyseal axis that controls these systems. Although CKD affects puberty, this life period also impacts the progression of CKD. Diabetes mellitus, posterior urethral valves, reflux nephropathy, and hypoplasia all appear to accelerate with sexual maturation. Potential mechanisms include increases in blood pressure and body size as well as altered endocrine physiology. Better understanding of the interactions of puberty and CKD may lead to better outcomes for children with CKD as well as longer preservation of native kidney function.
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Affiliation(s)
- Pascale H Lane
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE 68198-2169, USA.
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Canosa LF, Unniappan S, Peter RE. Periprandial changes in growth hormone release in goldfish: role of somatostatin, ghrelin, and gastrin-releasing peptide. Am J Physiol Regul Integr Comp Physiol 2005; 289:R125-33. [PMID: 15746304 DOI: 10.1152/ajpregu.00759.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In goldfish, growth hormone (GH) transiently rises 30 min after meals, returning to baseline at 1 h postmeal. Somatostatin (SRIF) is the major inhibitor of GH release. Three cDNAs encoding pre-pro-SRIF (PSS) have been previously cloned from goldfish brain: PSS-I, which encodes SRIF-14; PSS-II, which is potentially processed into gSRIF-28 that has [Glu1,Tyr7,Gly10]SRIF-14 at the COOH terminus; and PSS-III, which encodes [Pro2]SRIF-14 at its COOH terminus. In goldfish, bombesin (BBS), mimicking the endogenous gastrin-releasing peptide (GRP), acutely suppresses food intake and also stimulates GH release. Ghrelin was recently characterized in goldfish as a GH secretagogue and an orexigen. In this paper, we studied the changes in SRIF mRNA levels during feeding and analyzed the influences of BBS and ghrelin peptides on forebrain PSS expression. The results showed a 60% reduction in PSS-II mRNA after meals, but no changes in the expression of PSS-I and PSS-III were found. Intraperitoneal injections of 100 ng/g body wt of BBS increased GH secretion and decreased PSS-I and PSS-II gene expression. Intraperitoneal injection of goldfish ghrelin (100 ng/g body wt) transiently increased the serum GH levels and increased PSS-I, while decreasing PSS-II mRNA levels. Ghrelin (50 ng/g body wt) blocked the effects of BBS (100 ng/g body wt) on PSS-I but not on PSS-II expression. Coadministration of BBS and ghrelin decreased only the PSS-II gene expression. We conclude that the interactions between BBS/GRP and ghrelin can account for the postprandial variations in serum GH levels and the forebrain expression of PSS-II. Furthermore, we demonstrate that intraperitoneal administration of BBS reduces the ghrelin expression levels in the gut. Thus the inhibition of production of ghrelin in the gut may contribute to the satiety effects of BBS/GRP peptides.
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Affiliation(s)
- Luis Fabián Canosa
- Department of Biological Sciences, CW405 Biological Sciences Bldg., University of Alberta, Edmonton, AB, Canada T6G 2E9
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