A New Endocrine and Obesity Related Peptide

Ghrelin enables the stimulation of growth hormone release and control of energy balance.

Kojima, M. et al. Nature. 402, 656-660, 1999

Tschp, M. et al. Nature. 407, 908-913, 2000

Nakazato, M. et al. Nature. 409, 194-198, 2001

Hosoda, H, et al. J Biol Chem (2000 May 8)

Kojima, M, et al. Nature 402,656-660 (1999)

Wren A.M. et al, Endocrinology 141: 4325-4328, 2000

More references of Ghrelin



Measurement of circulating Ghrelin levels in fasting rat1 and human obesity2 by Phoenixs Ghrelin RIA Kit have been published in Nature and Diabetes.

Serum Ghrelin-ir in SD Rats: 1.26 0.14 ng/ml and the fasting SD Rats: 2.86 0.28 ng/ml (non-extracted)1;
Plasma Ghrelin-ir in lean Caucasians: 155 25 fmol/ml and obese Caucasians: 106 23 fmol/ml2.
1. Tschp, M. et al. Nature. 407, 908-913, 2000
2. Tschp, M. et al. Diabetes. 50, 707-709, 2001


Weight gain decreases elevated plasma ghrelin concentrations of patients with anorexia nervosa. Eur J Endocrinol 2001 Nov;145(5):669-73

Otto B, Cuntz U, Fruehauf E, Wawarta R, Folwaczny C, Riepl RL, Heiman ML, Lehnert P, Fichter M, Tschop M.

OBJECTIVE: Ghrelin is a new gastric hormone that has been identified as an endogenous ligand for the growth hormone (GH) secretagogue receptor subtype 1a (GHS-R1a). Ghrelin administration however not only stimulates GH secretion but also induces adiposity in rodents by increasing food intake and decreasing fat utilization. We hypothesized that impaired ghrelin secretion in anorexia nervosa may be involved in the pathogenesis of this eating disorder. To examine this hypothesis and to further investigate the role for ghrelin in regulating energy homeostasis, we analyzed circulating ghrelin levels in patients with anorexia nervosa and examined possible correlations with clinical parameters before and after weight gain. METHODS: Plasma ghrelin levels were measured in overnight fasting plasma samples from 36 female patients with anorexia nervosa (age: 25.0+/-1.2 years, BMI: 15.2+/-0.2 kg/m(2)) before and after weight gain following psychotherapeutic treatment intervention in a psychosomatic institution. Plasma ghrelin levels were also measured in fasting plasma samples from 24 age-matched female controls (31+/-1.4 years, BMI: 22.9+/-0.45 kg/m(2)). For quantification of ghrelin levels a commercially available radioimmunoassay (Phoenix Pharmaceuticals, USA) was used. RESULTS: Fasting plasma ghrelin levels in anorectic patients were significantly higher (1057+/-95 pg/ml) than in normal age-matched female controls (514+/-63 pg/ml n=24, P=0.02). Therapeutic intervention in a psychosomatic institution caused an BMI increase of 14% (P<0.001) leading to a significant decrease in circulating ghrelin levels of 25%, (P=0.001). A significant negative correlation between Delta ghrelin and Delta BMI was observed (correlation coefficient: -0.47, P=0.005, n=36). CONCLUSION: We show for the first time that fasting plasma levels of the novel appetite-modulating hormone ghrelin are elevated in anorexia nervosa and return to normal levels after partial weight recovery. These observations suggest the possible existence of ghrelin resistance in cachectic states such as caused by eating disorders. Future studies are necessary to investigate putative mechanisms of ghrelin resistance such as a possible impairment of intracellular ghrelin receptor signaling in pathophysiological states presenting with cachexia.


A Preprandial Rise in Plasma Ghrelin Levels Suggests a Role in Meal Initiation in Humans. Diabetes 50:1714-1719, 2001

David E. Cummings1, Jonathan Q. Purnell2, R. Scott Frayo1, Karin Schmidova1, Brent E. Wisse1 and David S. Weigle1

1 University of Washington, VA Puget Sound Health Care System and Harborview Medical Center, Seattle, Washington
2 Oregon Health Sciences University, Portland, Oregon

Plasma ghrelin levels increased nearly twofold immediately before each meal and fell to trough levels within 1 h after eating, a pattern reciprocal to that of insulin. Intermeal ghrelin levels displayed a diurnal rhythm that was exactly in phase with that of leptin, with both hormones rising throughout the day to a zenith at 0100, then falling overnight to a nadir at 0900. Ghrelin levels sampled during the troughs before and after breakfast correlated strongly with 24-h integrated area under the curve values (r = 0.873 and 0.954, respectively), suggesting that these convenient, single measurements might serve as surrogates for 24-h profiles to estimate overall ghrelin levels. Circulating ghrelin also correlated positively with age (r = 0.701). The clear preprandial rise and postprandial fall in plasma ghrelin levels support the hypothesis that ghrelin plays a physiological role in meal initiation in humans.
Plasma immunoreactive ghrelin levels were measured in duplicate using a commercial radioimmunoassay (RIA) that uses 125I-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin (Phoenix Pharmaceuticals, Belmont, CA). In our study, the lower and upper limits of detection for this assay were 80 and 2,500 pg/ml, respectively. All assays included 12 plasma control samples from common stocks that were transferred to aliquots and frozen at the beginning of the study, used to normalize each test for interassay variability. Based on these controls, the intra-assay coefficient of variation (CV) was 8.7% and the interassay CV was 14.6% (n = 10). No cross-reactivity was seen with human leptin, which was assessed at doubling dilutions from 100 to 1 ng/ml.



Normal plasma level of human Ghrelin = 87.7910.27 pg/ml (Mean SE, n=7)*

Normal plasma level of Rat Ghrelin =      74.87 8.22 pg/ml (Mean SE, n=10)*

Dr. C Y  Bowers, School of Medicine, Tulane University Medical Center

* Plasma was extracted using C18 column

Peptide M. W.

Conversion to SI Units 

Ghrelin (Human) 3371.92  1 pg/ml = 0.296 fmol/ml = 0.296 pM
Ghrelin (Rat) 3314.00  1 pg/ml = 0.302 fmol/ml = 0.302 pM



Extraction of  plasma sample  is not necessary with Phoenix's 

human Ghrelin RIA Kit 

Time of Use** Week 0 Week 2 Week 4
Extracted Samples**      
1 x 23.91pg (60pg/ml) 29.6pg (74.1pg/ml) 17.28pg (43pg/ml)
1/2 x 11.74pg 17.36pg 10.51pg
1/4 x 5.71pg 9.8pg 5.73pg
1/8 x 3.10pg 5.5pg 2.77pg
1/16 x 1.87pg 2.29pg 1.44pg
1/32 x 1.09pg 0.36pg 0.48pg
Non-extracted Samples***      
1 x 5.75pg (57.5pg/ml) 12.3pg (123pg/ml) 7.65pg (76.5pg/ml)
1/2 x 1.88pg 6.53pg 3.41pg
1/4 x   2.59pg 1.61pg
1/8 x   0.98pg 0.58pg
* Kits used in Week 0 were used within 2 days of manufacture. All kits used in Week 2 and 4 were stored as dry power (not reconstituted) at 4C.
** 1 ml of plasma (normal human subjects) was extracted with a C-18 column and the lyophilized elute rehydrated with 250 l RIA buffer. 100 l of this was used to perform the RIA. To calculate the level of Ghrelin-like immunoreactivity in 1ml, the level obtained by extrapolation of the standard curve must be multiplied by 2.5 to account for the dilution with RIA buffer (ex. 29.64 pg x 2.5 = 94.1 pg/ml).

***100 l of plasma (non-extracted, normal human subjects) was used to perform the RIA. To calculate the level of Ghrelin-like immunoreactivity, the level obtained by extrapolation of the standard curve must be multiplied by 10 to obtain the level at 1 ml (ex. 12.3 pg x 10 = 123 pg/ml).


Stability of Ghrelin (Human) RIA Kit

(at least 3 weeks in liquid form)

Time of Rehydrate B/T (%) R/T (%) ED20 (pg/tube) ED50 (pg/tube) ED80 (pg/tube)
hour 1 0.04 0.44 23.78 8.74 3.14
Day 2 0.04 0.52 14.19 5.51 2.19
Week 1 0.05 0.50 23.72 8.18 2.65
Week 2 0.03 0.43 38.21 11.88 4.57
Week 3 0.03 0.44 31.82 11.12 3.64
Rehydrate one kit contents with RIA buffer keep them at 4C. Kits was used in above scheduled time. 

Stability of Ghrelin (Human) RIA Kit

(at least 4 weeks in dry form)

Time of Use* B/T (%) R/T (%) ED20 (pg/tune) ED50 (pg/tune) ED80 (pg/tune)
Week 0 0.05 0.37 20.90 5.78 1.99
Week 2 0.03 0.45 19.03 8.25 3.14
Week 4 0.03 0.35 15.75 6.28 2.27
* Kits used in Week 0 were used within 2 days of manufacture. All kits used in Week 2 and 4 were stored as dry power (not reconstituted) at 4C.
Phoenix strongly recommends using the RIA kit as soon as possible. Always store the unused kit as dry power at  4C if not used immediately. Never store reconstituted kit components as they are unstable. Use of stored reconstituted kit components to perform RIA may yield poor and unacceptable results.

Phoenix's Ghrelin (Human) RIA Kit detects "total" Ghrelin, including Ser3- octanoyl and Ser3-des-octanoyl Ghrelins.


Circulating Ghrelin Levels Are Decreased in Human Obesity






Lean Pima 


Obese Pima 


n 7 8 7 8
Sex-Female 3 4 3 4
Sex-Male 4 4 4 4
Age (Years) 32 11 30 7 33 4 32 5
Body weight (kg) 71.4 9.8 109.8 16.8 70.3 9.6 109 15.2
BMI (kg/m2) 25.4 2.3 38.2 4.8 24.0 1.9 37.9 6.6
Body fat (%) 22 9 35 7 24 7 35 5
Plasma Ghrelin (fmol/ml) 155 25 106 23 95 13 80 36
Plasma Glucose (mg/dl) 87 7 91 4 89 6 95 7
Plasma Insulin (uU/ml) 4 3 10 3 6 3 18 10
Plasma Leptin (ng/ml) 8 7 53 47 10 9 35 27
Tschp, M., et al. Diabetes 50, 707-709, 2001



Matthias Tschp, et al. Circulating Ghrelin Levels Are Decreased in Human Obesity. Diabetes 50:707-709, 2001

Human plasma ghrelin was measured with a commercial radioimmunoassay (Phoenix Pharmaceuticals, Belmont, CA.) that uses 125I-labeled bioactive ghrelin as a tracer molecule and a polyclonal antibody raised in rabbits against full-length octanoylated human ghrelin. No cross-reactivity was found with human secretin, human vasoactive intestinal peptide, human prolactin releasing peptide-31, human galanin, human growth hormone (GH) releasing hormone, neuropeptide Y, or other relevant molecules. The interassay coefficient of variation (CV) was 9.013.6% (n = 10), and the intra-assay CV was 4.55.3%. Fasting plasma ghrelin concentrations were compared among the subgroups (sex, lean and obese, and Caucasian and Pima Indian) using analysis of variance. The relationships between fasting plasma ghrelin concentrations and various anthropometric and metabolic variables were examined by linear regression and Spearmans correlation coefficient analyses. Stepwise regression analysis was used to assess the relationship between fasting ghrelin concentrations and anthropometric and metabolic variables after adjusting for covariates. All of the analyses were performed using the SAS system, version 6.12 (Cary, NC).



Motilin-Related Peptide

A new gut peptide, is specifically expressed in enteroendocrine cells of the stomach. 1). The amino acid sequence of human Prepro- Motilin- Related Peptide/ m46 protein is completely identical with human prepro-Ghrelin  except Ser26 is not octanoylated. 2). The amino acid sequence of rat Pro-Motilin-Related Peptide/m46 Protein is also completely identical with rat Pro-Ghrelin except Ser26 is not octanoylated. 3). Human Motilin-Related Peptide/m46 Protein (24-41) is identical with human Des- octanoyl3- Ghrelin(1-18). 4). Rat and mouse Motilin-Related Peptide/m46 Protein (24-41) is also identical with rat Des-octanoyl3-Ghrelin.

Tomasetto C., et al. Gasenterology 119, 395-405 (2000)

Kojima, M, et al. Nature 402,656-660 (1999)

Review by Dr, Jaw-Kang Chang

Please visit Motilin-Related Peptide Page!


Immunofluorescence staining of Ghrelin in mouse stomach with Anti-Ghrelin (Rat) Antibody (1:800).

Dr. Frank Sundler

Neuroendocrine Cell Biology, University of Lund,  Sweden.









Peptide % Crossreactivity 
Ghrelin (Rat) 100
Ghrelin (Des-Octanoyl3) 100
Ghrelin (Human) 100
Ghrelin (23-28) (Human, Rat) 26.7
Ghrelin (1-14) (Des-Octanoyl3) (Human) 0
Ghrelin (1-5) (Des-Octanyl3) (Human, Rat) 0
Secretin (Human) 0
PrRP31(Rat) 0
PrRP31 (Human) 0
Galanin (Rat) 0
Galanin (Human) 0
GHRF (Rat) 0
GHRF (Human) 0
NPY (Human, Rat) 0
Orexin A 0
Orexin B (Human) 0
Orexin B (Mouse, Rat) 0



Long Lasting Antagonist for GHRH Receptor



Ghrelin in Obesity Research

Phoenix Pharmaceuticals has been the pioneer in obesity and neuroendocrine  research. We were the first to envision the importance of  peptides in obesity research and the first to offer Obesity Related Peptides Assay Kits (RIA, EIA, Western Blot Kits) to our customers. Using Phoenix's Ghrelin (Rat) RIA Kit, Ghrelin has been identified as an obesity related peptide to regulate energy balance which was published in Nature. [Tschop M, et al. Nature, 407, 908~913 (October 19, 2000)]





Des-Q14-Ghrelin (Rat)


031-45 $180/100g 198/100g
125I-Des-Q14-Ghrelin (Rat) T-031-45 $550/10Ci 605/10Ci
FAM-Des-Q14-Ghrelin (Rat) FG-031-45 $495/1.0nmole 545/1.0nmole
Des-Q14-Ghrelin (Rat) RIA Kit RK-031-45 $550/125 RIA tubes 605/125 RIA tubes

Ghrelin (Human)


031-30 $180/100g 198/100g
Ghrelin (Human) RIA Kit RK-031-30 $550/125 RIA tubes 605/125 RIA tubes
Ghrelin (Human) EIA Kit   EK-031-30 $495/96 wells 545/96 wells
Ghrelin (Human) Antibody for RIA (125 tubes) RAB-031-30 $250/125 RIA tubes 275/125 RIA tubes
Ghrelin (Human) Purified IgG G-031-30 $450/200g 495/200g
FAM-Ghrelin (Human) IgG FG-G-031-30 $450/200g 495/200g
Ghrelin (Human) Antibody for Immunohistochemistry H-031-30 $450/100l 495/100l

Prepro-Ghrelin (86-117) (Human) 


031-34 $140/100g 154/100g
Prepro-Ghrelin (86-117) (Human) RIA Kit RK-031-34 $550/125 RIA Tubes 605/125 RIA Tubes
Prepro-Ghrelin (86-117) (Human) Antibody for RIA RAB-031-34 $250/125 RIA Tubes 275/125 RIA Tubes
125I-Prepro-Ghrelin (86-117) (Human) Tracer T-031-34 $550/10uCi 605/10uCi
Prepro-Ghrelin (86-117) (Human) Dot Blot Kit DBK-031-34 $550/kit 605/kit
Anti-Prepro-Ghrelin (86-117) (Human) IgG G-031-34 $450/200ug 495/200ug
FAM-Anti-Prepro-Ghrelin (86-117) (Human) IgG  FG-G-031-34 $450/100ul 495/100ul
Rhodamine-Anti-Prepro-Ghrelin (86-117) (Human) IgG RG-G-031-34 $450/100ul 495/100ul
Anti-Prepro-Ghrelin (86-117) (Human) Antibody  H-031-34 $450/50ul 495/50ul

Prepro-Ghrelin (52-85)(Human) 


031-35 $140/100g 154/100g

Ghrelin (Human) (Des-Octanoyl3


031-32 $140/100g 154/100g
FAM-Ghrelin (Human) FG-031-30 $550/1.0nmole 605/1.0nmole
FAM-Ghrelin(Human) FAM-031-30 $550/1.0nmole 605/1.0nmole
125I-Ghrelin (Human) T-031-30 $550/10Ci 605/10Ci

Ghrelin (Mouse, Rat) 


031-31 $180/100g 198/100g
Ghrelin (Mouse, Rat) RIA Kit RK-031-31 $550/ 125 RIA tubes 605/ 125 RIA tubes
Ghrelin (Mouse, Rat) Western Blot Kit WBK-031-31 $550/Kit 605/Kit
Ghrelin (Mouse, Rat) Immunodot Blot Kit DBK-031-31 $550/Kit 605/Kit
Ghrelin (Mouse, Rat) Antibody for RIA  RAB-031-31 $250/125 RIA tubes 275/125 RIA tubes
Ghrelin (Mouse, Rat) Purified  IgG G-031-31 $450/200g 495/200g
FAM-Ghrelin (Mouse, Rat)  IgG FG-G-031-31 $450/100g 495/100g
Ghrelin (Mouse, Rat) Antibody for Immunohistochemistry H-031-31 $450/100l 495/100l

Ghrelin (3-28)(Rat) 


031-38  $180/100g  198/100g 

Prepro-Ghrelin (86-117) (Rat) 


031-36 $140/100g 154/100g

Prepro-Ghrelin (52-85) (Rat) 


031-37 $140/100g 154/100g

Ghrelin (Des-Octanoyl3) (Mouse, Rat) 


031-33 $140/100g 154/100g
125-I-Ghrelin (Rat) T-031-31 $550/10Ci 605/10Ci
FAM-Ghrelin (Rat) FG-031-31 $550/1.0nmole 605/1.0nmole
FAM-Ghrelin (Rat) FAM-031-31 $550/1.0nmole 605/1.0nmole
Ghrelin (1-14) (Human) 031-39 $120/100g 66/100g
Ghrelin (1-14) (Human) (Des-Octanoyl3) 031-40 $60/100g 132/100g
Ghrelin (1-5)-NH2 031-41 $60/200g $66/200g
Ghrelin (1-5)-NH2 (Des-Octanoyl3) 031-42 $30/200g 33/200g

Ghrelin (23-28) (H, R) C-terminal, Hexapeptide  


031-43 $50/200g 55/200g

Ghrelin (17-28) (Human, Rat)  


031-44 $120/200g 132/200g

More information of Motilin-Related Peptide

Product Name Code USD EURO
Motilin-Related Peptide (Human) [Des-octanyol3-Ghrelin (1-18) (Human)] 031-47 $140/100g 154/100g
FAM-Motilin-Related Peptide (Human) FG-031-47 $250/1.0nmole 275/1.0nmole
Rhodamine-Motilin-Related Peptide (Human) RG-031-47 $250/1.0nmole 275/1.0nmole
Motilin-Related Peptide (Mouse, Rat) [Des-octanyol3-Ghrelin (1-18) (M,R)] 031-48 $140/100g 154/100g
FAM-Motilin-Related Peptide (Mouse, Rat) FG-031-48 $250/1.0nmole 275/1.0nmole
Prepro-Motilin-Related Peptide (Mouse, Rat) RG-031-48 $250/1.0nmole 275/1.0nmole


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Last update on  02/06/2002 03:25:13 PM   by Jun Yang