Development of a Hypoparathyroid Male Rodent Model for Testing Delayed-Clearance PTH Molecules

Endocrinology ◽  
2021 ◽  
Vol 163 (2) ◽  
Author(s):  
Narjes Ramezanipour ◽  
Sayyed Hamid Zarkesh Esfahani ◽  
Richard Eastell ◽  
John Newell-Price ◽  
Graham Trevitt ◽  
...  
Keyword(s):  
Animal Model ◽  
Biological Activity ◽  
Single Dose ◽  
Wistar Rats ◽  
Biphasic Response ◽  
Serum Samples ◽  
Post Dose ◽  
Male Wistar Rats ◽  
Long Acting ◽  
Prolonged Response

Abstract Context Parathyroid hormone (PTH) replacement is a promising approach in the management of hypoparathyroidism but long-acting analogues need to be developed. To date, animal models for testing PTH required parathyroidectomy by surgery. We have developed a nonsurgical rodent hypoparathyroid model and tested a delayed-clearance PTH molecule (DC-PTH). Objective The aim of this study was to use cinacalcet to suppress calcium levels in normal rats and to reverse these effects with the administration of PTH or PTH analogues Methods Male Wistar rats were gavaged with either 30 mg/kg cinacalcet-HCl (cinacalcet) or vehicle only. Animals were then dosed with either single or repeated subcutaneous doses of PTH 1-34 or a DC-PTH at 20 nmol/kg. Control animals received vehicle only. Serum samples were analyzed for ionized calcium (iCa), phosphate, PTH, and DC-PTH. A pharmacokinetic-pharmacodynamic (PK-PD) model was built for cinacalcet, PTH 1-34, and DC-PTH using Phoenix64. Results Cinacalcet reduced iCa levels between 2 and 24 hours, returning to baseline by 72 hours post dose with nadir at 8 hours (analysis of variance P < .001), associated with a fall in rat PTH. For phosphate there was a variable biphasic response. Single-dose PTH abrogated the cinacalcet-induced fall in iCa for up to 2 hours. DC-PTH prevented the fall in iCa from 4 hours post dose and gave a prolonged response, with iCa levels quicker to return to baseline than controls. DC-PTH has a half-life of 11.5 hours, approximately 44 times longer than human PTH 1-34. The PK-PD models defined the reproducible effect of cinacalcet on iCa and that DC-PTH had prolonged biological activity. Conclusion The administration of cinacalcet provides a robust and reproducible nonsurgical animal model of hypoparathyroidism. DC-PTH holds promise for the treatment of hypoparathyroidism in the future.

scholarly journals SAT-396 A Non-Surgical Animal Model of Hypoparathyroidism for Testing PTH Analogues

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Narjes Ramezani-Pour ◽  
Sayyed Hamid Zarkesh Esfahani ◽  
Sarbendra Pradhananga ◽  
John D C Newell-Price ◽  
Richard John M Ross ◽  
...  
Keyword(s):  
Animal Model ◽  
Clinical Chemistry ◽  
T Test ◽  
Normal Male ◽  
Published Data ◽  
Serum Samples ◽  
Post Dose ◽  
Detection Assay ◽  
Male Wistar Rats

Abstract BACKGROUND: In vivo animal models for testing the pharmacokinetics and bioactivity of PTH and its analogues require parathyroidectomy by surgery (1, 2). As the parathyroid glands of rodents are very small the surgery often includes thyroidectomy, making this animal model time-limited, single use, complex, and expensive. We have developed a non-surgical rodent model of hypoparathyroidism using the Type II calcimimetic compound, Cinacalcet-HCl, to suppress PTH and thereby serum calcium levels. Methods: Normal male Wistar rats were gavaged with 30 mg/kg Cinacalcet-HCl (or vehicle only). To test the effect of PTH 1–34, animals were dosed immediately after Cinacalcet-HCl gavage with either a single subcutaneous injection of PTH at 20 nmol/kg or given as same dose repeated every hour for 6 hrs or vehicle only. Serum samples were analysed for ionised calcium (iCa) using an EasyLyte, fully automated electrolyte analyser (Medica Corporation) and phosphate using a Phosphorus Detection Assay Kit (Pars Azmun, IRAN) and an Hitachi 917 Clinical Chemistry Analyser. Results: Rats gavaged with 30 mg/kg Cinacalcet-HCl produced a significant reduction in iCa levels between 2-24hrs returning to baseline at 48-72hrs post dose with the nadir at 8 hours (ANOVA P < 0.0001). This equated to a 25% reduction in iCa at 8 hrs: mean±SD, iCa 1.19 ± 0.09 mmol/L at predose and 0.891 ± 0.04 mmol/L at 8 hours (t-test P < 0.0001). For phosphate there was an initial lowering within the first 2 hrs in all test groups but then a rise such that phosphate was at higher levels than control from 8–24 hrs (ANOVA, ns), returning to baseline at 48 hrs. PTH at 20 nmol/kg given as a single sc dose abrogated the Cinacalcet-HCl induced fall in iCa for up to 2 hrs (AUC±SD (mmol/L).hr, 0.076 ±0.047 versus 0.168±0.0874, t-test P=0.0289). Conclusions: We have shown that the administration of Cinacalcet-HCl provides a robust and reproducible lowering of calcium which is line with current published data (3). These studies demonstrate that the use of Cinacalcet-HCl in normal rats produces a hypocalcemic state that can be abrogated by the addition of PTH. This non-surgical animal model of hypoparathyroidism will be of value in testing the pharmacodynamics of PTH analogues. References 1. Shimizu M, et al. J Bone Miner Res. 2016;31(7):1405–12. 2. Jung SY, et al. PLoS One. 2016;11(10):e0163911-e. 3. Nemeth EF, et al. 2004;308(2):627–35.

scholarly journals SAT-408 Bioactivity of Long Acting PTH Fusion Molecules Tested in a Novel Non-Surgical Animal Model of Hypoparathyroidism

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Ian R Wilkinson ◽  
Narjes Ramezani-Pour ◽  
Sayyed Hamid Zarkesh Esfahani ◽  
Richard Eastell ◽  
Richard John M Ross
Keyword(s):  
Unmet Need ◽  
T Test ◽  
In Vivo Studies ◽  
Normal Male ◽  
Serum Samples ◽  
Post Dose ◽  
Long Acting ◽  
The Impact ◽  
Prolonged Response

Abstract Introduction: There is an unmet need for the development of long-acting PTH molecules to treat patients with hypoparathyroidism. We have established a novel non-surgical rodent model of hypoparathyroidism using oral Cinacalcet-HCl to test long acting analogues of PTH. Here we have tested the pharmacodynamics properties of two long acting PTH fusion molecules. Methods: PTH fusion molecules tested: Fusion-1 is PTH (1–34) linked to GHBP (residues 1–238), and Fusion-2 is a Hybrid PTH-PTHrP (1) linked to GHBP (residues 1–238). For in vivo studies, normal male wistar rats were gavaged with 30 mg/kg Cinacalcet-HCl, immediately followed by a subcutaneous dose of PTH Fusion at 20 nmol/kg. Control animals received PTH (1–34) and vehicle only. Serum samples were taken and analysed for ionised calcium (iCa). Results: Oral administration of Cinacalcet-HCl caused a reduction in iCa that was significantly different from vehicle controls at 2 to 24hrs post dose (ANOVA P < 0.0001). PTH 1–34 maintained iCa levels for 2 hours after administration above that of Cinacalcet-HCl (AUC±SD (mmol/L).hr from baseline, 0.076 ±0.047 and 0.168±0.0874, t-test P=0.0289) but then levels fell and recovered as for Cinacalcet-HCl alone. Subcutaneous doses of both fusions were able to abrogate the effects of Cinacalcet-HCl from 4hrs post dose onwards giving a prolonged response, with iCa levels quicker to return to baseline levels at 48hrs compared to Cinacalcet-HCl. The AUC±SD (mmol/L).hr from baseline for iCa over 72 hours was 3.93±1.4 for Fusion-1, 5.0±2.7 for Fusion-2 & 10±2.8 for Cinacaclet-HCl and were significantly reduced for both fusions compared to Cinacalcet-HCl alone (t-test P = 0.0028 & P = 0.019, respectively) and not significantly different from vehicle only. Conclusions: Cinacalcet-HCl behaved as expected in terms of iCa lowering (2). PTH maintained iCa but only for 2 hours. Both PTH fusion molecules showed a delayed and prolonged response and reduced the impact of Cinacalcet-HCl induced low iCa levels from 4hrs to 24hrs. These data provide proof of concept for long acting biological activity of these novel PTH fusion proteins. References: 1. Shimizu M, Joyashiki E, Noda H, Watanabe T, Okazaki M, Nagayasu M, et al. Pharmacodynamic Actions of a Long-Acting PTH Analog (LA-PTH) in Thyroparathyroidectomized (TPTX) Rats and Normal Monkeys. J Bone Miner Res. 2016;31(7):1405–12. 2. Nemeth EF, Heaton WH, Miller M, Fox J, Balandrin MF, Van Wagenen BC, et al. Pharmacodynamics of the type II calcimimetic compound cinacalcet HCl. The Journal of pharmacology and experimental therapeutics. 2004;308(2):627–35.

scholarly journals Development of Animal Model for Studying Deep Second-Degree Thermal Burns

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Danielle dos Santos Tavares Pereira ◽  
Maria Helena Madruga Lima-Ribeiro ◽  
Nicodemos Teles de Pontes-Filho ◽  
Ana Maria dos Anjos Carneiro-Leão ◽  
Maria Tereza dos Santos Correia
Keyword(s):  
Animal Model ◽  
Wistar Rats ◽  
Therapeutic Agents ◽  
Collagen Fibers ◽  
Thermal Burns ◽  
Thermal Lesions ◽  
Male Wistar Rats ◽  
Tissue Shrinkage ◽  
Fibroblastic Proliferation ◽  
Second Degree

Thermal lesions were produced in 12 male Wistar rats, positioning a massive aluminum bar 10 mm in diameter (51 g), preheated to 99°C ± 2°C/10 min. on the back of each animal for 15 sec. After 7, 14, 21, and 28 days, animals were euthanized. The edema intensity was mild, with no bubble and formation of a thick and dry crust from the 3rd day. The percentage of tissue shrinkage at 28 days was 66.67 ± 1.66%. There was no sign of infection, bleeding, or secretion. Within 28 days reepithelialization was incomplete, with fibroblastic proliferation and moderate fibrosis and presence of modeled dense collagen fibers. It is concluded that the model established is applicable in obtaining deep second-degree thermal burns in order to evaluate the healing action of therapeutic agents of topical use.

scholarly journals Long-Acting Glucagon-Like Peptide-1 Receptor Agonists Suppress Voluntary Alcohol Intake in Male Wistar Rats

2020 ◽  
Vol 14 ◽  
Author(s):  
Vincent N. Marty ◽  
Mehdi Farokhnia ◽  
Joseph J. Munier ◽  
Yatendra Mulpuri ◽  
Lorenzo Leggio ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Alcohol Intake ◽  
Ethanol Intake ◽  
Addictive Behaviors ◽  
Gut Hormone ◽  
Male Wistar Rats ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Long Acting ◽  
Alcohol Seeking

Alcohol use disorder (AUD) is a chronic relapsing condition characterized by compulsive alcohol-seeking behaviors, with serious detrimental health consequences. Despite high prevalence and societal burden, available approved medications to treat AUD are limited in number and efficacy, highlighting a critical need for more and novel pharmacotherapies. Glucagon-like peptide-1 (GLP-1) is a gut hormone and neuropeptide involved in the regulation of food intake and glucose metabolism via GLP-1 receptors (GLP-1Rs). GLP-1 analogs are approved for clinical use for diabetes and obesity. Recently, the GLP-1 system has been shown to play a role in the neurobiology of addictive behaviors, including alcohol seeking and consumption. Here we investigated the effects of different pharmacological manipulations of the GLP-1 system on escalated alcohol intake and preference in male Wistar rats exposed to intermittent access 2-bottle choice of 10% ethanol or water. Administration of AR231453 and APD668, two different agonists of G-protein receptor 119, whose activation increases GLP-1 release from intestinal L-cells, did not affect voluntary ethanol intake. By contrast, injections of either liraglutide or semaglutide, two long-acting GLP-1 analogs, potently decreased ethanol intake. These effects, however, were transient, lasting no longer than 48 h. Semaglutide, but not liraglutide, also reduced ethanol preference on the day of injection. As expected, both analogs induced a reduction in body weight. Co-administration of exendin 9-39, a GLP-1R antagonist, did not prevent liraglutide- or semaglutide-induced effects in this study. Injection of exendin 9-39 alone, or blockade of dipeptidyl peptidase-4, an enzyme responsible for GLP-1 degradation, via injection of sitagliptin, did not affect ethanol intake or preference. Our findings suggest that among medications targeting the GLP-1 system, GLP-1 analogs may represent novel and promising pharmacological tools for AUD treatment.

scholarly journals The Protective Effects of Turmeric on Liver Enzymes of Metronidazole-Treated Adult Male Wistar Rats

2015 ◽  
Vol 1 (6) ◽  
pp. 255
Author(s):  
Akudike C. J. ◽  
Chukwu V. O. ◽  
Ezejindu D. N. ◽  
Ihim A. C.
Keyword(s):  
Adult Male ◽  
Wistar Rats ◽  
Liver Enzymes ◽  
Antimicrobial Effect ◽  
The Body ◽  
Protective Effects ◽  
Negative Effects ◽  
Serum Samples ◽  
Male Wistar Rats ◽  
Anti Oxidant

Over the years, research works on the different liver enzymes has proven to be very helpful to man. This study evaluates the protective effects of turmeric on the liver enzymes of metronidazole-treated adult male wistar rats. With previous researches, metronidazole has been found to exert some negative effects on some organs of the body like the testis, kidney etc but the turmeric on its own part, has been found to have no side effects with a host of beneficial functions such as its anti-oxidant and antimicrobial effect amongst a host of other functions. In this study, twenty wistar rats with weight range of between 165-180g were assigned into four groups A, B, C and D of 5 each. The experimental groups A, B and C were orally administered 200mg of metronidazole, 400mg of metronidazole and 400mg of metronidazole as well as 400mg of turmeric respectively for duration of twenty-eight days while the group D served as control and were orally administered water and feed only. Twenty four hours after the last administration, the animals were anaesthetized under chloroform inhalation and dissected for organ collection. Blood for serum preparation was collected into sterile plain tubes and stored in the refrigerator for analysis. Serum samples from the bloods were analyzed for liver enzymes activities using randox kit method. The study revealed that turmeric helped reduced the effects of metronidazole on the serum activities of ALT, AST and ALP on the liver. This present study suggests that metronidazole could have negative effects on the liver and so advises that turmeric be added when on metronidazole administration.

scholarly journals Effect of Hydroalcoholic Extract ofCydonia oblongaMiller (Quince) on Sexual Behaviour of Wistar Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Muhammad Aslam ◽  
Ali Akbar Sial
Keyword(s):  
Body Weight ◽  
Single Dose ◽  
Sexual Behaviour ◽  
Wistar Rats ◽  
Sexually Active ◽  
Cydonia Oblonga ◽  
Hydroalcoholic Extract ◽  
Male Wistar Rats ◽  
Mating Performance ◽  
Remarkable Manner

Cydonia oblongaMiller (quince) is regarded as a potent libido invigorator in Tib-e-Nabvi and Unani System of Medicine. This study was carried out to evaluate the aphrodisiac activity of the hydroalcoholic extract of the fruits ofCydonia oblongaMiller (quince) in Wistar rats. The extract was administered orally by gavage in the dose of 500 mg/kg and 800 mg/kg body weight per day as a single dose for 28 days. The observed parameters were mounting frequency, assessment of mating performance, and orientation activities towards females, towards the environment, and towards self. The results showed that after administration of the extract mounting frequency and the mating performance of the rats increased highly significantlyP<0.01. The extract also influenced the behaviour of treated animals in comparison to nontreated rats in a remarkable manner, making them more attracted to females. These effects were observed in sexually active male Wistar rats.

scholarly journals Effect of Carcinogen 1,2-Dimethylhydrazine Treatment on Fiber Types in Skeletal Muscles of Male Wistar Rats

2017 ◽  
pp. 845-858
Author(s):  
V. SMERDU ◽  
M. PERŠE
Keyword(s):  
Animal Model ◽  
Wistar Rats ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Fiber Types ◽  
Variable Response ◽  
Hybrid Fiber ◽  
Control Male ◽  
Male Wistar Rats ◽  
Isoform Expression

The cancerogen 1,2-dimethylhydrazine (DMH), widely used in the experimental animal model of carcinogenesis, affects various organs, but its effect on muscle fibers is unknown. To evaluate the effect of 15-week DMH treatment on the fiber size and myosin heavy chain (MyHC) isoforms, which substantially determine fiber types and their contractile characteristics, pure and hybrid fiber types were immunohistochemically determined according to the MyHC isoform expression in soleus, extensor digitorum longus, gastrocnemius medialis and lateralis muscles of DMH-treated and control male Wistar rats. Whereas the size of fibers was mostly unaffected, the MyHC isoform expression was partially affected in both gastrocnemius samples, but not in the soleus and extensor digitorum longus of DMH-treated rats. The lower proportions of hybrid fiber types and especially that of type 1/2x in most gastrocnemius samples of DMH-treated rats resulted in a shift towards a single MyHC isoform expression, but the extent and pattern of the MyHC isoform shift varied across the different gastrocnemius samples. Such variable response to DMH treatment across muscles indicates that each muscle possesses its own adaptive range. These findings are essential for an accurate evaluation of skeletal muscle characteristics in DMH animal model.

scholarly journals Peptide fragments of bradykinin show unexpected biological activity not mediated by B1 or B2 receptors

2021 ◽  
Author(s):  
Igor Souza-Silva ◽  
Cristiane de Paula ◽  
Lucas Bolais-Ramos ◽  
Anderson Santos ◽  
Filipe da Silva ◽  
...  
Keyword(s):  
Biological Activity ◽  
Adult Male ◽  
Wistar Rats ◽  
Vascular Reactivity ◽  
Biological Activities ◽  
No Production ◽  
Peptide Fragments ◽  
Kinin System ◽  
Male Wistar Rats

Background and purpose: Bradykinin [BK-(1-9)] is an endogenous nonapeptide involved in multiple physiological and pathological processes. A long-held belief is that peptide fragments of BK-(1-9) are biologically inactive. Here, we have tested the biological activities of BK-(1-9) and two major peptide fragments in human and animal systems. Experimental Approach: Levels of BK peptides in male Wistar rat plasma were quantified by mass spectrometric methods. Nitric oxide was quantified in human, mouse and rat cells, and loaded with DAF-FM. We used aortic rings from adult male Wistar rats to test vascular reactivity. Changes in blood pressure and heart rate were measured in conscious adult male Wistar rats. Key results: Plasma levels of BK-(1-7) and BK-(1-5) in rats were increased following infusion of BK-(1-9). All tested peptides induced NO production in all cell types tested. However, unlike BK-(1-9), NO production elicited by BK-(1-7) or BK-(1-5) was not inhibited by B or B receptor antagonists. BK-(1-7) or BK-(1-5) also induced concentration-dependent vasorelaxation of aortic rings, without involving B or B receptors. In vivo, either intravenous or intra-arterial administration of BK-(1-7) or BK-(1-5) induced similar hypotension response. Conclusions and implications: BK-(1-7) and BK-(1-5) are endogenous peptides present in plasma. They are formed, at least partially, through the BK-(1-9) proteolysis. BK-related peptide fragments show biological activity, not mediated by B or B receptors. These BK-fragments could constitute new, active components of the kallikrein-kinin system.

scholarly journals Male Wistar rats show individual differences in an animal model of conformity

2011 ◽  
Vol 14 (5) ◽  
Author(s):  
Jolle W. Jolles ◽  
Leonie de Visser ◽  
Ruud van den Bos
Keyword(s):  
Animal Model ◽  
Individual Differences ◽  
Wistar Rats ◽  
Male Wistar Rats

Influence of quinidine, fluvoxamine, and ketoconazole on the enantioselective pharmacokinetics of citalopram in rats

2008 ◽  
Vol 86 (11) ◽  
pp. 770-776 ◽  
Author(s):  
Adriana Rocha ◽  
Eduardo B. Coelho ◽  
Vera L. Lanchote
Keyword(s):  
Single Dose ◽  
Wistar Rats ◽  
Vehicle Control ◽  
Racemic Mixture ◽  
Blood Samples ◽  
Chiralcel Od ◽  
Male Wistar Rats ◽  
Enantioselective Pharmacokinetics ◽  
Enantioselective Metabolism ◽  
Cyp Inhibitors

Citalopram (CITA) is available as a racemic mixture or as (+)-(S)-CITA. In humans, CITA is metabolized to demethylcitalopram (DCITA) by CYP2C19, CYP2D6, and CYP3A and to didemethylcitalopram by CYP2D6. There are no data regarding the enzymes involved in CITA and DCITA metabolism in rats. The present study investigated the influence of CYP inhibitors on the enantioselective metabolism of CITA in rats. Male Wistar rats (n = 6) received a single dose of 20 mg·kg–1 CITA after pretreatment with 80 mg·kg–1 quinidine, 10 mg·kg–1 fluvoxamine, 50 mg·kg–1 ketoconazole, or vehicle (control). Blood samples were collected up to 20 h after CITA administration. The CITA and DCITA enantiomers were analyzed by LC-MS/MS using a Chiralcel OD-R column. The kinetic disposition of CITA was enantioselective in rats (AUCS/R ratio = 0.4). Coadministration with quinidine resulted in non-enantioselective inhibition of the metabolism of CITA. Coadministration with fluvoxamine or ketoconazole, however, inhibited only the metabolism of (+)-(S)-CITA, but not of (–)-(R)-CITA when the racemic drug was administered to rats.

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