Sincalide targets the cholecystokinin 1 receptor (CCK1R) and cholecystokinin 2 receptor (CCK2R). [3][4]
In H9c2 cardiomyoblast cells (rat embryonic heart-derived cell line), both CCK1R and CCK2R are expressed at mRNA and protein levels. The protective effect of CCK-8 against angiotensin II-induced apoptosis is primarily mediated through CCK1R, as the CCK1R antagonist Devazepide (10 μM) significantly blocked this effect, while the CCK2R antagonist L365260 (20 μM) did not. [3]

In H9c2 rat cardiomyoblast cells, CCK-8 (1 μM) pretreatment for 2 hours significantly attenuates angiotensin II (Ang II, 1 μM)-induced cytotoxicity and apoptosis. CCK-8 treatment increases cell viability (from ~60% to ~80%), reduces the percentage of apoptotic cells (from 10.89% to 5.07% by flow cytometry), and decreases TUNEL-positive nuclei. CCK-8 alone (0.001-100 μM) shows no cytotoxicity. [3]
Mechanistically, CCK-8 reverses Ang II-induced changes: it increases p-Akt (Ser473) and p-Bad expression, restores Bcl-2 levels, and decreases Bax and cleaved-caspase-3 expression. The protective effect is blocked by the PI3K inhibitor LY294002 (20 μM) and the CCK1R antagonist Devazepide (10 μM), indicating involvement of the CCK1R/PI3K/Akt signaling pathway. [3]
In H9c2 cells, Ang II (1 μM, 24 h) increases CCK mRNA and protein expression but decreases CCK1R protein and mRNA expression; CCK2R expression remains unchanged. [3]

---

Sincalide (Cholecystokinin octapeptide, CCK‐8), a novel cardiovascular hormone, significantly inhibits myocardial fibrosis in noninfarcted regions. Additionally, CCK-8 is beneficial in the fight against apoptosis, inflammation, and collagen deposition. In part, CCK-8 prevents Ang II-induced apoptosis in H9c2 cardiomyoblasts by activating the CCK1 receptor and PI3K/Akt (phosphatidylinositol-3 kinase/protein kinase B) signaling pathway[3].

Myocardial infarction (MI) rat model: Male Sprague-Dawley rats subjected to left anterior descending coronary artery ligation receive intraperitoneal injection of CCK-8 (50 μg/kg/day) for 28 days. CCK-8 treatment improves cardiac function: at 4 weeks post-MI, left ventricular ejection fraction (LVEF) is higher (79.4% vs 43.3% in saline group) and left ventricular internal diameter at end-systole (LVIDs) is lower (3.53 mm vs 7.22 mm) compared to saline-treated MI rats. CCK-8 reduces myocardial fibrosis in the non-infarcted region, as shown by Masson's trichrome staining (collagen volume fraction reduced from ~12% to ~6%), and decreases collagen I, collagen III, fibronectin, MMP-2, MMP-9, CTGF, and TGF-β1 expression by western blot and immunohistochemistry. RNA-seq shows that CCK-8 downregulates fibrosis-related genes (e.g., collagens, MMPs, CTGF, GDF-15, galectin-3). [4]
Pharmacodynamic studies in humans: For gallbladder contraction, sincalide is administered intravenously at 0.02 μg/kg over 30-60 seconds; if no contraction within 15 minutes, a second dose may be given. For pancreatic function testing (with secretin), sincalide 0.02 μg/kg is infused over 30 minutes. For small bowel transit acceleration, sincalide 0.04 μg/kg is given intravenously over 30-60 seconds. For sphincter of Oddi manometry, 0.02 μg/kg is used. [1][2]

---

Sincalide (Cholecystokinin octapeptide, CCK‐8) (i.p.; 50 μg/kg/d; for 4 weeks) reduces fibrosis in the noninfarcted areas and delays the development of heart failure and left ventricular remodeling in a MI rat model[4].

Cell viability (CCK-8 assay): H9c2 cells (4 × 10³/well) in 96-well plates are treated with CCK-8 (0.001-100 μM) or Ang II (0.01-10 μM) for 24 hours. After adding CCK-8 solution (10 μL/well) and incubating for 1.5 hours, absorbance is measured at 450 nm. [3]
Hoechst 33342 staining for apoptosis: Cells are fixed with 4% paraformaldehyde, stained with Hoechst 33342 (10 μg/mL) for 10 minutes, and imaged under fluorescence microscopy. Apoptotic cells show nuclear fragmentation and chromatin condensation. [3]
TUNEL assay: Cells are fixed, permeabilized with 0.1% Triton X-100, incubated with biotin-conjugated dUTP and terminal transferase for 1 hour, counterstained with DAPI, and visualized. [3]
Flow cytometry (Annexin V-FITC/PI): Cells are harvested, washed, resuspended in binding buffer, stained with Annexin V-FITC and PI, and analyzed by flow cytometry. [3]
Western blotting: Total protein is extracted, separated by SDS-PAGE, transferred to PVDF membranes, blocked, incubated with primary antibodies (anti-CCK, anti-CCK1R, anti-CCK2R, anti-p-Akt, anti-Akt, anti-p-Bad, anti-Bad, anti-Bax, anti-Bcl-2, anti-cleaved-caspase-3, anti-GAPDH), then with HRP-conjugated secondary antibodies, and detected. [3]

---

Cell Line: H9c2 cells
Concentration: 0.001, 0.01, 0.1, 1, 10, or 100 μmol/L
Incubation Time: 24 h
Result: Attenuated Ang II‐induced toxicity in H9c2 cells

Rat MI model: Male Sprague-Dawley rats (200-220 g, 6-7 weeks old) are anesthetized with 10% chloral hydrate (3 mL/kg, i.p.), intubated, and mechanically ventilated. Left anterior descending coronary artery is ligated with 6-0 sutures through the fourth intercostal space. Successful ligation is confirmed by ST-segment elevation on ECG and color changes in the ischemic area. Rats receive intramuscular penicillin (2.5 × 10⁴ U) post-surgery. CCK-8 (50 μg/kg/day) or equal volume of normal saline is administered intraperitoneally for 28 days. [4]
Echocardiography in rats: Ultrasound machine with a 12-MHz transducer is used. Two-dimensional M-mode echocardiography is performed to assess left ventricular function and structural parameters (IVSs, IVSd, LVIDd, LVIDs, LVEF, LVFS). Measurements are taken before surgery, at 2 weeks, and at 4 weeks post-surgery. [4]

---

MI rat model
50 μg/kg
i.p.; 50 μg/kg/d; for 4 weeks

Absorption, Distribution and Excretion
Intravenous injection (bolus) of syncallilide rapidly induces gallbladder contraction, reaching maximum contraction within 5 to 15 minutes, while gallbladder contraction induced by a fatty meal is progressive, reaching maximum contraction after approximately 40 minutes. Limited information is available regarding the elimination pathway of syncallilide. Limited information is available regarding the volume of distribution of syncallilide. Metabolism/Metabolites Limited information is available regarding the metabolism of syncallilide. Biological Half-Life Limited information is available regarding the half-life of syncallilide.

---

For clinical use, sincalide is reconstituted by adding 5 mL sterile water for injection to a 5 μg vial (final concentration 1 μg/mL). The solution may be stored at room temperature for 24 hours. For intravenous infusion, sincalide is diluted in 0.9% sodium chloride injection. [1]

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Sincalitone is a synthetic cholecystokinin octapeptide analog. Due to its molecular weight of 1143, sincalitone is likely to be present in very low concentrations in breast milk, and it is unlikely to be orally absorbed by the infant, as it is likely to be destroyed in the infant's gastrointestinal tract. Sincalitone has a serum half-life of less than 2 minutes, meaning that pausing breastfeeding for 10 minutes after administration ensures that the infant is not exposed to the drug.
◉ Effects on Breastfed Infants
No published information found as of the revision date.
◉ Effects on Lactation and Breast Milk
No published information found as of the revision date.

---

Protein Binding
Limited information regarding protein binding of sincalitone.

---

Human adverse events: The most frequent side effects are abdominal pain and nausea. Rapid intravenous injection (0.04 μg/kg) causes transient abdominal cramping in approximately 20% of patients. Other reactions (occurring in ~1-2% of patients) include dizziness, vomiting, flushing, sweating, rash, hypotension, hypertension, shortness of breath, urge to defecate, headache, diarrhea, sneezing, and numbness. Reactions are generally mild and short duration. [1]
Overdosage symptoms (from animal studies): In dogs, overdosage symptoms include hypotension, bradycardia, syncope, and electrocardiogram changes, attributed to sincalide-induced vagal stimulation. These effects are prevented by atropine or bilateral vagotomy. No instances of overdosage in humans have been reported. [1]
Contraindications: Known hypersensitivity, intestinal obstruction, pregnancy (especially near term due to risk of premature labor), and nursing mothers (excretion in milk unknown). [1]
Drugs inhibiting gallbladder contraction (should be withheld for 48 hours before testing): opiates, anticholinergic drugs, nifedipine, indomethacin, octreotide, theophylline, benzodiazepines, phentolamine, isoproterenol, progesterone. Nicotine and alcohol should also be avoided. [2]

[1]. Kinevac (sincalide for injection)/Squibb Diagnostics. Gastroenterol Nurs. 1991 Oct;14(2):98-100.

[2]. Sincalide: A Review of Clinical Utility, Proper Infusion Methodology, and Alternative Cholecystogogues. J Nucl Med Technol. 2019 Sep;47(3):210-212.

[3]. Protective effect of cholecystokinin octapeptide on angiotensin II-induced apoptosis in H9c2 cardiomyoblast cells. J Cell Biochem. 2020 Jul;121(7):3560-3569.

[4]. Cholecystokinin octapeptide reduces myocardial fibrosis and improves cardiac remodeling in post myocardial infarction rats. Int J Biochem Cell Biol. 2020 Aug;125:105793.

Sincalide is an oligopeptide. Sincalide is an injectable drug used to aid in the diagnosis of gallbladder and pancreatic diseases. It has been identified as the 8-amino acid C-terminal fragment of cholecystokinin, also known as CCK-8. Naturally occurring cholecystokinin is a gastrointestinal peptide hormone that is generally essential for stimulating the digestion of proteins and fats in the body. Intravenous injection of sincalide can significantly reduce gallbladder volume by inducing gallbladder contraction. The resulting bile excretion is similar to the physiological bile excretion induced by endogenous cholecystokinin. In addition, sincalide can stimulate the pancreas to secrete bicarbonate and enzymes. Sincalide, marketed under the brand name Kinevac (FDA approved), is used to stimulate the duodenum, pancreas, and small intestine for cholesterol analysis, enzyme activity analysis, and X-ray examination, respectively. Sincalide is a cholecystokinin analogue. Sincalide is a synthetic C-terminal octapeptide with the same sequence as the endogenous cholecystokinin hormone. Sincalitone mimics the action of cholecystokinin, directly inducing gallbladder smooth muscle contraction, thereby reducing gallbladder volume and promoting bile emptying and pancreatic enzyme secretion. In addition, the drug also reduces lower esophageal sphincter tone and delays gastric emptying through the cholinergic signaling pathway. Cholecystokinin is an octapeptide hormone found in the intestines and brain. When secreted from the gastric mucosa, it stimulates the gallbladder to release bile and stimulates the pancreas to release digestive enzymes.

---

Drug Indications
Sincalitone (trade name: Kinevac, FDA approved) is used for the following indications: (1) Stimulating gallbladder contraction, which can be assessed by various diagnostic imaging methods or by obtaining concentrated bile samples through duodenal aspiration for analysis of cholesterol, bile acids, phospholipids and crystals; (2) In combination with secretin, stimulating pancreatic secretion, followed by duodenal aspiration for analysis of enzyme activity, composition and cytology; (3) Accelerating the passage of barium meals through the small intestine, thereby reducing the time and radiation dose required for intestinal fluoroscopy and X-ray examination.
FDA Label

---

Mechanism of Action
Intravenous administration of simcalitone causes gallbladder contraction, resulting in a significant reduction in gallbladder volume. The resulting bile expulsion is similar to physiological bile expulsion induced by endogenous cholecystokinin. Like cholecystokinin, simcalitone stimulates pancreatic secretion; co-administration with secretin increases the amount of pancreatic secretion and the output of bicarbonate and proteins (enzymes). The combined action of secretin and simcalitone allows for the assessment of specific pancreatic functions by measuring and analyzing duodenal aspirates.

---

Pharmacodynamics
Following intravenous (bolus) administration of 0.02 mcg/kg simcalitone, the gallbladder reaches maximum contraction within 5 to 15 minutes. Simcalitone reduces the radiographic volume of the gallbladder by at least 40%, which is generally considered a satisfactory contraction.

---

Proper infusion methodology: Sincalide cholescintigraphy for chronic acalculous gallbladder disease requires a 60-minute infusion of 0.02 μg/kg. Infusions of 3-15 minutes produce wide variability in gallbladder ejection fraction (GBEF) and cannot establish normal reference values; they also cause nausea and abdominal cramping in healthy subjects. With the 60-minute infusion, normal GBEF is ≥38%. Short infusions (3-15 minutes) may result in false-positive studies, potentially leading to unnecessary cholecystectomy. [2]
Alternative to sincalide: When sincalide is unavailable, pharmacy-compounded sincalide or fatty meals may be used. Fatty meals require >10 g fat and have established reference values (e.g., Ensure Plus: abnormal GBEF <33%; 250 mL milk: abnormal GBEF <51%). Fatty meals are problematic in patients with delayed gastric emptying (gastroparesis). [2]
Sincalide for gallbladder emptying before cholescintigraphy: Indicated when patient has not eaten for >24 hours or is receiving hyperalimentation, to empty the gallbladder of viscous bile that may prevent entry of the hepatobiliary radiopharmaceutical. [2]
Mechanism: Sincalide stimulates gallbladder contraction (approx. 50% volume evacuated within 15 minutes), relaxes the sphincter of Oddi, and stimulates pancreatic secretion of bicarbonate and protein. [1]

C49H62N10O16S3

1143.26898

1142.35

C, 51.48; H, 5.47; N, 12.25; O, 22.39; S, 8.41

25126-32-3

Sincalide ammonium; 70706-98-8

9833444

Asp-{SO3H-Tyr}-Met-Gly-Trp-Met-Asp-Phe-NH2
L-alpha-aspartyl-O4-sulfo-L-tyrosyl-L-methionyl-glycyl-L-tryptophyl-L-methionyl-L-alpha-aspartyl-L-phenylalaninamide

DXMGWMDF
D-{SO3H-Tyr}-MGWMDF-NH2

White to off-white solid powder

1.4±0.1 g/cm3

1.643

2.25

13

19

33

78

2180

7

CSCC[C@H](NC([C@@H](NC([C@@H](N)CC(O)=O)=O)CC1=CC=C(OS(=O)(O)=O)C=C1)=O)C(NCC(N[C@H](C(N[C@H](C(N[C@H](C(N[C@H](C(N)=O)CC2=CC=CC=C2)=O)CC(O)=O)=O)CCSC)=O)CC3=CNC4=CC=CC=C34)=O)=O

IZTQOLKUZKXIRV-YRVFCXMDSA-N

InChI=1S/C49H62N10O16S3/c1-76-18-16-34(55-47(69)37(58-44(66)32(50)23-41(61)62)21-28-12-14-30(15-13-28)75-78(72,73)74)45(67)53-26-40(60)54-38(22-29-25-52-33-11-7-6-10-31(29)33)48(70)56-35(17-19-77-2)46(68)59-39(24-42(63)64)49(71)57-36(43(51)65)20-27-8-4-3-5-9-27/h3-15,25,32,34-39,52H,16-24,26,50H2,1-2H3,(H2,51,65)(H,53,67)(H,54,60)(H,55,69)(H,56,70)(H,57,71)(H,58,66)(H,59,68)(H,61,62)(H,63,64)(H,72,73,74)/t32-,34-,35-,36-,37-,38-,39-/m0/s1

(3S)-3-amino-4-[[(2S)-1-[[(2S)-1-[[2-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-amino-1-oxo-3-phenylpropan-2-yl]amino]-3-carboxy-1-oxopropan-2-yl]amino]-4-methylsulfanyl-1-oxobutan-2-yl]amino]-3-(1H-indol-3-yl)-1-oxopropan-2-yl]amino]-2-oxoethyl]amino]-4-methylsulfanyl-1-oxobutan-2-yl]amino]-1-oxo-3-(4-sulfooxyphenyl)propan-2-yl]amino]-4-oxobutanoic acid

CCK-8S; Sincalide; 25126-32-3; CCK8S; Kinevac; Sincalida; CCK 8S; CCK8S; Kinevac; CCK-8; CCK 8; CCK8

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O: ~50 mg/mL (~43.7 mM)
DMF: ~50 mg/mL (~43.7 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (2.19 mM) (saturation unknown) in 10% DMF 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.

---

 (Please use freshly prepared in vivo formulations for optimal results.)