InVivoSIM GIPR/GLP‑1R Dual Agonist (Tirzepatide Biosimilar)

in vivo functional assay

Hu W, Gong W, Yang F, Cheng R, Zhang G, Gan L, Zhu Y, Qin W, Gao Y, Li X, Liu J. (2025). "Dual GIP and GLP-1 receptor agonist tirzepatide alleviates hepatic steatosis and modulates gut microbiota and bile acid metabolism in diabetic mice" Int Immunopharmacol . PubMed

Tirzepatide is a dual agonist of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors and is a promising therapeutic option for type 2 diabetes mellitus (T2DM). Nevertheless, its effect and underlying mechanism on hepatic steatosis remain ambiguous. Herein, we explored the impact of tirzepatide on improving hepatic steatosis in diabetic mice, with a particular focus on the gut microbiota and bile acids (BAs) using animal models. The tirzepatide effectively reduced body weight, improved insulin resistance, decreased serum and hepatic lipid levels, and mitigated liver injury. Compared to semaglutide, tirzepatide exhibited superior efficacy in reducing hepatic lipid accumulation. 16S rRNA gene sequencing and targeted metabolomics of BAs revealed that tirzepatide ameliorated gut microbiota dysbiosis and BAs metabolism in diabetic mice. Notably, tirzepatide observably increased the abundance of beneficial genera such as Akkermansia, elevated the ratio of farnesoid X receptor (FXR) antagonists (glycoursodeoxycholic acid: GUDCA, β-muricholic acid: β-MCA, hyodeoxycholic acid: HDCA, ursodeoxycholic acid: UDCA) to natural agonists (cholic acid: CA, lithocholic acid: LCA, chenodeoxycholic acid: CDCA, glycocholic acid: GCA, taurodeoxycholic acid: TDCA), and reduced FXR expression in intestinal tissues. In conclusion, tirzepatide attenuated hepatic steatosis in diabetic mice and regulated the gut microbiota and BAs metabolism, which may help to provide a novel therapeutic approach and therapeutic target for metabolic dysfunction-associated steatotic liver disease (MASLD).

in vivo functional assay, in vitro functional assay

Borner T, Pataro AM, Doebley SA, Furst CD, White AD, Gao SX, Chow A, Sanchez-Navarro MJ, Ghidewon MY, Halas JG, Mohiby AZ, Willard FS, Grill HJ, Ai M, Samms RJ, Hayes MR, De Jonghe BC. (2025). "Hypophagia and body weight loss by tirzepatide are accompanied by fewer GI adverse events compared to semaglutide in preclinical models" Sci Adv 11(25):eadu1589. PubMed

Glucagon-like peptide-1 receptor (GLP-1R)/glucose-dependent insulinotropic peptide receptor (GIPR) agonistic analogs have yielded superior results in enhancing glycemic control and weight management compared to GLP-1R agonism alone. Intriguingly, GIPR agonism appears to induce antiemetic effects, potentially alleviating part of the nausea and vomiting side effects common to GLP-1R agonists like semaglutide. Here, we show in rats and shrews that GIPR agonism blocks emesis and attenuates other malaise behaviors elicited by GLP-1R activation while maintaining reduced food intake and body weight loss and improved glucose tolerance. The GLP-1R/GIPR agonist tirzepatide induced significantly fewer side effects than equipotent doses of semaglutide. These findings underscore the therapeutic potential of combined pharmaceutical strategies activating both incretin systems, leading to enhanced therapeutic index and reduced occurrence of nausea and vomiting for obesity and diabetes treatments.

in vivo functional assay

2025. (2025). "Pharmacological weight loss with incretin-based therapies does not result in a disproportionate loss of muscle mass or function in obese mice and humans" medRxiv . PubMed

The new generation of incretin-based therapies are potent anti-obesity medications (AOMs) that offer the first non-surgical treatment for 936 million patients globally suffering from being overweight or obese[1]. However, clinical data suggest that incretin-mimetics could cause a disproportionate decrease in lean body mass (LBM) [2, 3], raising a concern for deterioration of skeletal muscle and acceleration of sarcopenic obesity[4]. Unfortunately, muscle mass and function are not routinely assessed in obesity studies and original data on the matter remains sparse. In this work, we conducted various pre-clinical studies and a proof-of-concept clinical trial to examine how skeletal muscle is affected by AOMs. We found that in mice with diet-induced obesity (DIO), incretin-based therapies result predominantly in a substantial decrease in fat mass alongside a small but significant decrease in LBM. Among the lean tissues, the decrease in liver mass exceeded the change in muscle mass robustly. While absolute muscle mass did decrease, relative muscle mass (i.e., the muscle mass to body weight (BW) ratio) improved significantly. Similarly, we found that absolute muscle strength decreased mildly but increased relative to the BW of mice. The relative preservation of muscle was also associated with marked improvement in running performance. Additionally, during a scenario of extreme muscle wasting (i.e., immobilization), DIO mice on incretin-based therapies did not experience more muscle loss than calorie-matched, pair-fed mice. Finally, in our clinical proof-of-concept trial, patients on AOMs significantly decreased BW, which was accompanied by a mild decrease in absolute LBM but an improvement in relative LBM. Muscle function as indicated by maximum voluntary contraction (MVC) did not decrease. Overall, these data suggest that in middle-aged obese mice and men, incretin-based therapies do cause a mild decrease in absolute muscle mass and strength that is offset by a more pronounced decrease in fat and liver mass, resulting in an improved muscle to BW ratio, function, and mobility.

in vivo functional assay

Hegedűs ZI, Jakab ME, Gergely TG, Sayour NV, Kovács A, Antal S, Kovács T, Ferdinandy P, Varga ZV, Tóth VE. (2025). "Tirzepatide, a dual GIP/GLP1-receptor co-agonist preserves cardiac function and improves survival in angiotensin II-induced heart failure model in mice: comparison to liraglutide" Cardiovasc Diabetol 24(1):253. PubMed

Background: Incretin analogues, used for the treatment of type 2 diabetes mellitus and obesity, such as GLP1-receptor agonist liraglutide (Lira) have been shown to reduce major adverse cardiac events in recent clinical trials of heart failure. Tirzepatide (TZP), a dual GIP/GLP1-receptor agonist has shown promising results in the SUMMIT trial as improved cardiovascular outcomes in patients with heart failure with preserved ejection fraction (HFpEF). However, data regarding their use in heart failure with reduced ejection fraction (HFrEF) is lacking. We performed a head-to-head comparative study in a mouse model of non-ischaemic cardiac injury induced by continuous angiotensin II (AngII) infusion, as AngII is a key driver of both heart failure forms. Methods: Osmotic minipumps were inserted for subcutaneous (s.c.) administration of AngII (1.5 mg/kg/day) in 5-month-old male Balb/c mice or sham surgery was performed. Animals were treated with vehicle (Veh), Lira (300 µg/day i.p.) or TZP (48 µg/day s.c.) for 14 days in the following groups: Sham/Veh (n = 7), AngII/Veh (n = 15), Sham/Lira (n = 7), AngII/Lira (n = 15), Sham/TZP (n = 8), AngII/TZP (n = 15). Cardiac structural, functional and molecular characteristics were assessed by echocardiography, ECG, immunohistochemistry, flow cytometry and qRT-PCR. Results: Mortality was significantly higher in AngII/Veh animals compared to controls, while AngII/TZP mice showed significantly reduced mortality after 14 days of treatment. Both Lira and TZP caused significant weight reduction compared to controls. AngII given alone also reduced body mass, and this reduction was further enhanced by TZP. Treatment with both compounds preserved cardiac systolic and diastolic function compared with AngII/Veh animals, as shown by normal ejection fraction and E/e', respectively. Both Lira and TZP decreased the AngII-induced elevation of cardiac fibrosis and hypertrophy markers, including Ctgf, Col1a1, Col3a1, and Nppa, while TZP also reduced the elevated Nppb level. TZP also reduced systemic inflammation, as shown by the reduction in serum CRP levels. Conclusions: Lira and TZP preserved cardiac function and decreased markers of hypertrophy and fibrosis in mice with AngII-induced heart failure, whereas TZP also significantly decreased mortality. In addition to HFpEF, the use of incretin analogues may also be of clinical relevance in the treatment of HFrEF. However, as patients with heart failure, AngII level is elevated and can cause weight loss/cachexia, the usage of incretin analogues to treat non-obese heart failure patients should be considered.

in vitro functional assay

Gojani EG, Wang B, Li D, Kovalchuk O, Kovalchuk I. (2025). "Single and Combined Impact of Semaglutide, Tirzepatide, and Metformin on β-Cell Maintenance and Function Under High-Glucose-High-Lipid Conditions: A Comparative Study" Int J Mol Sci Gojani EG, Wang B, Li D, Kovalchuk O, Kovalchuk I. PubMed

Type 2 diabetes (T2D), the most common form, is marked by insulin resistance and β-cell failure. β-cell dysfunction under high-glucose-high-lipid (HG-HL) conditions is a key contributor to the progression of T2D. This study evaluates the comparative effects of 10 nM semaglutide, 10 nM tirzepatide, and 1 mM metformin, both alone and in combination, on INS-1 β-cell maintenance and function under HG-HL conditions. INS-1 cells were pretreated for 2 h with single doses of metformin (1 mM), semaglutide (10 nM), tirzepatide (10 nM), or combinations of 1 mM metformin with either 10 nM semaglutide or 10 nM tirzepatide, followed by 48 h of HG-HL stimulation. The results indicate that combining 1 mM metformin with either 10 nM semaglutide or 10 nM tirzepatide significantly enhances the effects of 10 nM semaglutide and 10 nM tirzepatide on HG-HL-induced apoptosis and dysregulated cell cycle. Specifically, the combination treatments demonstrated superior restoration of glucose-stimulated insulin secretion (GSIS) functionality compared to 1 mM metformin, 10 nM semaglutide, and 10 nM tirzepatide.

in vivo functional assay

Pacini G, Ahrén B. (2024). "The dual incretin co-agonist tirzepatide increases both insulin secretion and glucose effectiveness in model experiments in mice" Peptides . PubMed

Tirzepatide is a dual GIP and GLP-1 receptor co-agonist which is approved for glucose-lowering therapy in type 2 diabetes. Here, we explored its effects on beta cell function, insulin sensitivity and insulin-independent glucose elimination (glucose effectiveness) in normal mice. Anesthetized female C57/BL/6 J mice were injected intravenously with saline or glucose (0.125, 0.35 or 0.75 g/kg) with or without simultaneous administration of synthetic tirzepatide (3 nmol/kg). Samples were taken at 0, 1, 5, 10, 20 and 50 min. Glucose elimination rate was estimated by the percentage reduction in glucose from min 5 to min 20 (K_G). The 50 min areas under the curve (AUC) for insulin and glucose were determined. Beta cell function was assessed as AUC_insulin divided by AUC_glucose. Insulin sensitivity (S_I) and glucose effectiveness (S_G) were determined by minimal model analysis of the insulin and glucose data. Tirzepatide glucose-dependently reduced glucose levels and increased insulin levels. The slope for the regression of AUC_insulin versus AUC_glucose was increased 7-fold by tirzepatide from 0.014 ± 0.004 with glucose only to 0.099 ± 0.016 (P < 0.001). S_I was not affected by tirzepatide, whereas S_G was increased by 78% (P < 0.001). The increase in S_G contributed to an increase in K_G by 74 ± 4% after glucose alone and by 67 ± 8% after glucose+ tirzepatide, whereas contribution by S_I times AUC_insulin insulin (i.e., disposition index) was 26 ± 4% and 33 ± 8%, respectively. In conclusion, tirzepatide stimulates both insulin secretion and glucose effectiveness, with stimulation of glucose effectiveness being the prominent process to reduce glucose.

in vivo functional assay

Iwamoto Y, Kimura T, Dan K, Iwamoto H, Sanada J, Fushimi Y, Katakura Y, Shimoda M, Yamasaki Y, Nogami Y, Shirakiya Y, Nakanishi S, Mune T, Kaku K, Kaneto H. (2024). "Tirzepatide, a dual glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor agonist, exhibits favourable effects on pancreatic β-cells and hepatic steatosis in obese type 2 diabetic db/db mice" Aim: Tirzepatide, a dual agonist of glucagon-like peptide receptor and glucose-dependent insulinotropic polypeptide receptor, is expected to exhibit high clinical efficacy in obese type 2 diabetic patients. We evaluated the effects of tirzepatide on pancreatic β-cells and the liver, an insulin-target organ, in a mouse model of obese type 2 diabetes mellitus. Materials and methods: Obese type 2 diabetic db/db mice (BKS.Cg-/+ Leprdb/+ Leprdb/Jcl*) were used in this study. Starting at 7 weeks of age, mice were treated with tirzepatide (30 nmol/kg, subcutaneous injection twice a week) or semaglutide (200 nmol/kg, subcutaneous injection twice a week). The control group received phosphate-buffered saline (40-50 μL/subcutaneous injection twice a week). After 4 weeks of drug administration, pancreatic β-cells and the liver were removed and examined. Results: Compared to the control group, blood glucose and body weight were significantly reduced in the group that received either tirzepatide or semaglutide (p < 0.001 and p < 0.05, respectively). Fasting insulin was significantly higher in the semaglutide and tirzepatide groups compared to the control group (p < 0.001). β-Cell mass and quality of insulin granules in β-cells similarly increased in the semaglutide and tirzepatide groups compared to the control group (p < 0.05 and p < 0.001, respectively). The fat staining area in the liver in oil red O staining and the liver-spleen ratio in computed tomography showed improvement only in the tirzepatide group (p < 0.001 and p < 0.005, respectively). Liver macrophage M1/M2 ratio similarly improved with semaglutide and tirzepatide (p < 0.05). Conclusion: Tirzepatide and semaglutide exhibited similar potent glucose-lowering effects. At concentrations used in the present experiments, tirzepatide exhibited more beneficial effects on β-cell-related gene expression, insulin granule count and glucose-stimulated insulin secretion compared to semaglutide. In addition, tirzepatide exhibited a stronger favourable effect on hepatic fat deposition and improved inflammation in the liver. This is the first report showing that tirzepatide, a novel diabetes drug, exhibits a superior effect on pancreatic β-cells and the liver of obese type 2 diabetic mice. 26(12):5982-5994. PubMed

Aim: Tirzepatide, a dual agonist of glucagon-like peptide receptor and glucose-dependent insulinotropic polypeptide receptor, is expected to exhibit high clinical efficacy in obese type 2 diabetic patients. We evaluated the effects of tirzepatide on pancreatic β-cells and the liver, an insulin-target organ, in a mouse model of obese type 2 diabetes mellitus. Materials and methods: Obese type 2 diabetic db/db mice (BKS.Cg-/+ Leprdb/+ Leprdb/Jcl*) were used in this study. Starting at 7 weeks of age, mice were treated with tirzepatide (30 nmol/kg, subcutaneous injection twice a week) or semaglutide (200 nmol/kg, subcutaneous injection twice a week). The control group received phosphate-buffered saline (40-50 μL/subcutaneous injection twice a week). After 4 weeks of drug administration, pancreatic β-cells and the liver were removed and examined. Results: Compared to the control group, blood glucose and body weight were significantly reduced in the group that received either tirzepatide or semaglutide (p < 0.001 and p < 0.05, respectively). Fasting insulin was significantly higher in the semaglutide and tirzepatide groups compared to the control group (p < 0.001). β-Cell mass and quality of insulin granules in β-cells similarly increased in the semaglutide and tirzepatide groups compared to the control group (p < 0.05 and p < 0.001, respectively). The fat staining area in the liver in oil red O staining and the liver-spleen ratio in computed tomography showed improvement only in the tirzepatide group (p < 0.001 and p < 0.005, respectively). Liver macrophage M1/M2 ratio similarly improved with semaglutide and tirzepatide (p < 0.05). Conclusion: Tirzepatide and semaglutide exhibited similar potent glucose-lowering effects. At concentrations used in the present experiments, tirzepatide exhibited more beneficial effects on β-cell-related gene expression, insulin granule count and glucose-stimulated insulin secretion compared to semaglutide. In addition, tirzepatide exhibited a stronger favourable effect on hepatic fat deposition and improved inflammation in the liver. This is the first report showing that tirzepatide, a novel diabetes drug, exhibits a superior effect on pancreatic β-cells and the liver of obese type 2 diabetic mice.

in vivo functional assay

Lv F, Cai X, Lin C, Yang W, Ji L. (2024). "Effects of Semaglutide and Tirzepatide on Bone Metabolism in Type 2 Diabetic Mice" Pharmaceuticals (Basel) 17(12):1655. PubMed

Background/Objectives: Type 2 diabetes and weight loss are associated with detrimental skeletal health. Incretin-based therapies (GLP-1 receptor agonists, and dual GIP/GLP-1 receptor agonists) are used clinically to treat diabetes and obesity. The potential effects of semaglutide and tirzepatide on bone metabolism in type 2 diabetic mice remain uncertain. Methods: Combined streptozotocin and high fat feeding were employed in female C57BL/6J mice to promote hyperglycemia. Mice were administered for 4 weeks with a saline vehicle (sc., once-daily), semaglutide (40 μg/kg/d, sc., every three days), or tirzepatide (10 nmol/kg, sc., once-daily). Bone strength was assessed by three-point bending. Femur microarchitecture was determined by micro-CT, and bone formation and resorption parameters were measured by histomorphometric analysis. Serum was collected to measure bone resorption (C-telopeptide fragments of type I collagen, CTX) and formation (procollagen type 1 N-terminal propeptide, P1NP) biomarkers, respectively. The expression of bone metabolism-related genes was evaluated in the bone using RT-PCR. Results: Glucose levels significantly reduced after 4 weeks of semaglutide and tirzepatide treatment (both p < 0.05) compared with vehicle treatment. Tirzepatide led to more weight loss than semaglutide. Compared to saline-treated diabetic mice, the mean femur length was shorter in the tirzepatide group. After treatment with tirzepatide or semaglutide, cortical bone and trabecular bone parameters did not change significantly compared to saline-treated diabetic mice, except that cortical thickness was lower in the semaglutide group compared to the saline group (p = 0.032). Though CTX and P1NP levels decreased, however, the change in CTX and P1NP levels did not differ among the four groups during the 4 weeks of treatment (all p > 0.05). Semaglutide affected RANKL and OPG mRNA expression and increased the ratio of OPG/RANKL. No significant difference was found in the quantity of Col1a1, RANKL, OPG, and RUNX2 between tirzepatide- and saline-treated diabetic mice. Conclusions: The 4-week treatment with semaglutide and tirzepatide had a neutral effect on bone mass compared with the controls, and most of the bone microarchitecture parameters were also comparable between groups in diabetic mice. A better understanding of incretin-based therapies on bone metabolism in patients with diabetes requires further evaluation in large clinical trials.

in vivo functional assay

Kong W, Deng B, Shen X, John C, Haag J, Sinha N, Lee D, Sun W, Chen S, Zhang H, Clontz A, Hursting SD, Zhou C, Bae-Jump V. (2024). "Tirzepatide as an innovative treatment strategy in a pre-clinical model of obesity-driven endometrial cancer" Gynecol Oncol . PubMed

Objective: Interventions that combat obesity and its associated metabolic perturbations may decrease incidence and improve outcomes of endometrial cancer (EC). Potential options for weight loss include pharmacotherapeutic interventions such as tirzepatide, a dual-acting glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP) receptor agonist. Given this, we explored the anti-obesity and anti-tumorigenic effects of tirzepatide in our pre-clinical mouse model of endometrioid EC. Methods: Starting at 4 weeks of age, Lkb1^fl/flp53^fl/fl mice were fed a low-fat diet vs a high-fat diet to generate a lean or obese phenotype. Nine weeks after induction of EC, obese and lean mice were randomized to receive tirzepatide for 4 weeks. Body and tumor weights, tumor transcriptomic and metabolomic profiles, and serum metabolic markers and chemokines were assessed. Results: Both obese and lean mice began to lose body weight after 2 weeks of tirzepatide treatment, ultimately achieving a significant weight loss of 20.1 % in obese mice and 16.8 % in lean mice. Tirzepatide improved obesity-induced serum adiponectin, leptin, GIP, and C-reactive protein levels. Furthermore, tirzepatide relative to vehicle, effectively reduced tumor growth in obese and lean mice, inhibited the ErbB signaling and glycolysis/gluconeogenesis in tumors of obese mice, and increased O-linked glycosylation biosynthesis and phospholipase D signaling in tumors of lean mice. Conclusion: Tirzepatide decreased both mouse weight and tumor growth via effects on metabolic and immune pathways in the EC tumors that differed between obese and lean mice. This novel weight loss treatment deserves further evaluation as an innovative strategy in the management of EC.

in vitro functional assay

Regmi A, Aihara E, Christe ME, Varga G, Beyer TP, Ruan X, Beebe E, O', Farrell LS, Bellinger MA, Austin AK, Lin Y, Hu H, Konkol DL, Wojnicki S, Holland AK, Friedrich JL, Brown RA, Estelle AS, Badger HS, Gaidosh GS, Kooijman S, Rensen PCN, Coskun T, Thomas MK, Roell W. (2024). "Tirzepatide modulates the regulation of adipocyte nutrient metabolism through long-acting activation of the GIP receptor" Cell Metab 36(7):1534-1549.e7. PubMed

Tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor (GIPR/GLP-1R) agonist, has, in clinical trials, demonstrated greater reductions in glucose, body weight, and triglyceride levels compared with selective GLP-1R agonists in people with type 2 diabetes (T2D). However, cellular mechanisms by which GIPR agonism may contribute to these improved efficacy outcomes have not been fully defined. Using human adipocyte and mouse models, we investigated how long-acting GIPR agonists regulate fasted and fed adipocyte functions. In functional assays, GIPR agonism enhanced insulin signaling, augmented glucose uptake, and increased the conversion of glucose to glycerol in a cooperative manner with insulin; however, in the absence of insulin, GIPR agonists increased lipolysis. In diet-induced obese mice treated with a long-acting GIPR agonist, circulating triglyceride levels were reduced during oral lipid challenge, and lipoprotein-derived fatty acid uptake into adipose tissue was increased. Our findings support a model for long-acting GIPR agonists to modulate both fasted and fed adipose tissue function differentially by cooperating with insulin to augment glucose and lipid clearance in the fed state while enhancing lipid release when insulin levels are reduced in the fasted state.

in vivo functional assay

Toki S, Zhang J, Printz RL, Newcomb DC, Cahill KN, Niswender KD, Peebles RS. (2023). "Dual GIPR and GLP-1R agonist tirzepatide inhibits aeroallergen-induced allergic airway inflammation in mouse model of obese asthma" Clin Exp Allergy 53(2):216-221. PubMed

ex vivo functional assay

Willard FS, Douros JD, Gabe MB, Showalter AD, Wainscott DB, Suter TM, Capozzi ME, van der Velden WJ, Stutsman C, Cardona GR, Urva S, Emmerson PJ, Holst JJ, D', Alessio DA, Coghlan MP, Rosenkilde MM, Campbell JE, Sloop KW. (2020). "Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist" JCI Insight 5(17):e140532. PubMed

Tirzepatide (LY3298176) is a dual GIP and GLP-1 receptor agonist under development for the treatment of type 2 diabetes mellitus (T2DM), obesity, and nonalcoholic steatohepatitis. Early phase trials in T2DM indicate that tirzepatide improves clinical outcomes beyond those achieved by a selective GLP-1 receptor agonist. Therefore, we hypothesized that the integrated potency and signaling properties of tirzepatide provide a unique pharmacological profile tailored for improving broad metabolic control. Here, we establish methodology for calculating occupancy of each receptor for clinically efficacious doses of the drug. This analysis reveals a greater degree of engagement of tirzepatide for the GIP receptor than the GLP-1 receptor, corroborating an imbalanced mechanism of action. Pharmacologically, signaling studies demonstrate that tirzepatide mimics the actions of native GIP at the GIP receptor but shows bias at the GLP-1 receptor to favor cAMP generation over β-arrestin recruitment, coincident with a weaker ability to drive GLP-1 receptor internalization compared with GLP-1. Experiments in primary islets reveal β-arrestin1 limits the insulin response to GLP-1, but not GIP or tirzepatide, suggesting that the biased agonism of tirzepatide enhances insulin secretion. Imbalance toward GIP receptor, combined with distinct signaling properties at the GLP-1 receptor, together may account for the promising efficacy of this investigational agent.