• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.295-302
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• 2007

Leptin, the product of the obese(ob) gene, is an adipocyte-derived hormone for the regulation of whole- body energy storage and energy usage. It has been reported that the homozygous mutations in the gene for leptin(LEP) induce obesity and reduce energy expenditure. In cattle, LEP has significant roles directly or indirectly related with phenotypes such as body weight and fat deposits, therefore SNPs of LEP have been considered important genetic marker to estimate carcass fat content in cattle. In this study, SNPs were screened in LEP(2,222 bp) between intron 1 to 3'-UTR from 24 independent Hanwoo(Korean cattle) by PCR and DNA sequencing. Total 25 SNPs were found and two nonsynonymous SNPs including T1163A(V19E) and G3256A(G132D) were newly detected only from Hanwoo. Among 20 SNPs previously reported in cattle, 16 SNPs were found in Hanwoo; however, the frequencies of some SNPs were significantly different between Hanwoo and western cattle breeds. The other 4 SNPs were not detected from Hanwoo. These Hanwoo specific SNP patterns in LEP will be used in development of molecular marker and application to genetic improvement of Hanwoo.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.8-16
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• 2005

Leptin, the product of the ob gene, is primarily produced and released from adipocytes and acts on the hypothalamus to decrease food intake and increase energy expenditure. Defect in leptin or leptin receptors results in severe metabolic syndromes such as obesity, diabetes, and hypertension Evidence suggests that leptin plays beyond a satiety factor; in fact, it is a pluripotent player In regulation of numerous body functions. Although its actions have been relatively well studied in mammals scanty data are available in birds. In this article, recent advances in understanding of the roles of leptin in chicken physiology are reviewed with the focus on the effects on food intake, lipid metabolism, development and reproduction, and stress.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1689-1695
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• 2008

Leptin, the hormone product of the obese gene, is secreted predominately from white adipose tissue and regulates feed intake, energy metabolism and body composition. It has been considered a candidate gene for performance, carcass and meat quality traits in beef cattle. The objective of this study was to identify SNPs in the promoter region of the leptin gene and to evaluate the possible association of the SNP genotypes with carcass and meat quality traits in Korean cattle. We identified a total of 25 SNPs in the promoter region (1,208-3,049 bp upstream from the transcription start site) of the leptin gene, eleven (g.1508C>G, g.1540G>A, g.1545G>A, g.1551C>T, g.1746T>G, g.1798ins(G), g.1932del(T), g.1933del(T), g.1934del(T), g.1993C>T and g.2033C>T) of which have not been reported previously. Their sequences were deposited in GenBank database with accession number DQ202319. Genotyping of the SNPs located at positions g.2418C>G and g.2423G>A within the promoter region was performed by direct sequencing and PCR-SSCP method to investigate the effects of SNP genotypes on carcass and meat quality traits in Korean cattle. The SNP and SSCP genotypes from the two mutations of the leptin promoter were shown to be associated with the BF trait. The average BF value of animals with heterozygous SNP genotype was significantly greater than that of animals with the homozygous SNP genotypes for the g.2418C>G and g.2423G>A SNPs (p<0.05). Analysis of the combined genotype effect in both SNPs showed that animals with the AC SSCP genotype had higher BF value than animals with BB or AA SSCP genotypes (p<0.05). These results suggest that SNP of the leptin promoter region may be useful markers for selection of economic traits in Korean cattle.

• Journal of Community Nutrition
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• v.8 no.2
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• pp.69-75
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• 2006

Adipose tissue has now been recognized as a rich source of metabolically active molecules that include leptin and angiotensinogen (AGT), the precursor of angiotensin II (Ang II). Both of which have been implicated in the pathogenesis of metabolic alteration and hypertension associated with obesity. In this study, we examined the relationship between body mass index (BMI), adipocyte size, leptin, Ang II secretion and mRNA expression in human adipose tissue obtained from female subjects. Leptin and Ang II were analyzed using specific radioimmunoassay kits following a 48hour tissue culture. Leptin and Ang II secretion varied from 1.4 - 72.1ng/g and 0.8 - 57.3pg/g of tissue respectively. These large individual variations limit significant correlation between BMI, leptin and Ang II secretion. Ang II secretion was significantly higher in the obese than the non-obese (p < 0.05) and positively correlated with BMI. However, no difference in leptin secretion between the obese and the non-obese was observed and leptin secretion showed negative correlation with BMI. No difference in leptin and AGT mRNA expression in adipose tissue between the obese and the non-obese was observed. Although several limitations of this study, we found increased Ang II secretion in obese patients compared with non-obese patients, and positive correlation between AGT and BMI. Observed difference in AGT expression between the obese and the non-obese in this study might be of importance in relation with obesity related hypertension. (J Community Nutrition 8(2): 69-75, 2006)

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.8
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• pp.1062-1068
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• 2004

Leptin has a major role in the regulation of food intake and energy homeostasis. In addition, leptin participates in many physiological functions including regulation of lipid metabolism. Bovine recombinant leptin protein was produced in E. coli cells in order to understand function of leptin in the regulation of lipid metabolism. The leptin expression vector was constructed in pGEX-4T-3 vector and transformed into E. coli BL21 cells. Expression of the GST-leptin fusion protein was induced with IPTG. The fusion protein was purified using glutathione sepharose 4B batch method, and the recombinant leptin was eluted after thrombin protease digestion. The effect of leptin on glucose transport was examined in the differentiated adipocytes of 3T3-L1 cells. Leptin had no effect on basal and insulin-stimulated glucose transport in 3T3-L1 cells (p>0.05). Effect of recombinant leptin on glucose and acetate transport was examined in adipose tissues of Korean cattle (Hanwoo). Insulin stimulated glucose transport in both intramuscular and subcutaneous adipose tissues (p<0.05), but leptin did not affect glucose transport in both adipose tissues (p>0.05). Insulin stimulated acetate transport in bovine adipose tissues (p<0.05), but leptin did not affect acetate transport (p>0.05). Northern and RT-PCR analyses showed that mRNA levels of uncoupling protein-2 were increased by leptin treatment in 3T3-L1 cells without statistical difference (p>0.05). In conclusion, bovine recombinant leptin did not affect glucose and acetate transport in both 3T3-L1 adipocytes and bovine adipose tissues, while it stimulates UCP-2 mRNA expression in 3T3-L1 cells.

• Development and Reproduction
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• v.2 no.2
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• pp.173-178
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• 1998

Leptin, the product of the obese gene, is produced by adipose tissue and is known to be a hormone concerned with regulation of appetite and metabolism. Recent reports have shown that leptin is associated not only with obesity but also with female reproduction, but it has not yet been ascertained whether leptin acts directly on the ovaries or indirectly via the hypothalamus or pituitary pathway. The object of this study is to determine the expression of leptin and its receptor in the ovaries of 3 and 8 weeks old rats by immunohistochemistry and RT-PCR. In the ovaries of 3 and 8 weeks old rats, leptin was stained in the theca cells and portions of granulosa cells of atretic follicles, whereas leptin receptors was stained in interstitial cells and ova of preantral follicles. The RT-PCR results showed that leptin receptor mRNA was expressed in the ovaries of both immature and adult rats, while leptin mRNA was not. In conclusion, leptin mRNA was not expressed in the ovaries, however, leptin was detected by immunohistochemistry. Compared to leptin itself, leptin receptors in the ovaries were ascertained by both RT-PCR and immunohistochemistry. These results suggest that leptin is related to the regulation of the physiological functions of the ovaries.

• Development and Reproduction
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• v.6 no.2
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• pp.123-129
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• 2002

Leptin, a product of the obese gene, is associated not only with obesity but also with female reproductive function, but it has not yet been ascertained whether leptin acts directly on the ovary or indirectly via the hypothalamus-pituitary pathway. Therefore, the object of this study was to investigate the expession of leptin and its receptor in the rat ovary by immunohistochemistry and RT-PCR during the estrous cycle. Immunohistochemistry results showed that leptin was stained in the theca cells and in part of granulosa cells in atretic follicles, whereas leptin receptor was localized in the interstitial cells and ova in preantral follicies. In particular, leptin and its receptor in atretic follicles displayed more intensive staining compared to those in normal follicles. During the estrous cycle, the mRNA expression of leptin and its receptor in the ovary was detected by RT-PCR and estradiol, progesterone, and leptin levels in the serum was measured by ELISA. The leptin level in the serum on metestrous phase was significantly higher than that on estrous phase. Similar to leptin level, progesterone level increased on metestrous phase. Leptin mRNA was not detected throughout the estrous cycle, whereas leptin receptor mRNA was expressed on all phases of estrous cycle excepting the diestrous phase. These results suggest that leptin might be directly involved in the regulation of ovarian function in rat.

• The Journal of Korean Medicine
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• v.29 no.2
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• pp.116-132
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• 2008

Objective: This study investigated the effects of Bimanbang-1 (肥滿1號方: here in after referred to BMB-1) on the obese gene and obese inhibitory. Methods: C57BL/6 mice were induced by high fat diet. Mice were divided into three groups (normal, high fat diet with control, high fat diet with BMB-1 extract) and fed for 15 weeks. Items of this experimental study are as follows: body weight change, final body weight, the weight change of the adipocytes in body, the level change of LFT, NEFA and creatinine, the expression of ${\beta}3AR$ and leptin gene in primary adipocytes, the production change of leptin in primary adipocytes, the expression of ${\beta}3AR$, leptin and $TNF-{\alpha}$ in adipocytes tissue. Result: 1. All experimental groups showedthat the weight change decreased considerably and the high density group showedthat the final weight decreased considerably. 2. The high density group showed that the amount of the adipocyte in weight decreased considerably. 3. All experimental groups showedthat the amount of ALT decreased considerably, and AST decreased in the high density group. However, the amount of creatinine and glucose did not increase considerably. 4. All experimental groups showed that the amount of total cholesterol, LDL-cholesterol, triglyceride, and NEFA decreased, and HDL-cholesterol increased considerably. 5. The high density groups showedthat the amount of leptin decreased considerably. 6. All experimental groups showed that the revelation of ${\beta}3AR$ in primary adipose cell and 3T3-L1 cell increased considerably, and that the revelation of leptin and $TNF-{\alpha}$ in primary adipose cellsand 3T3-L1 cells decreased considerably. 7. All experimental groups showed that the size of adipocyte in adipocytes tissue decreased. 8. All experimental groups showed that the adipose vacuoles in liver tissue decreased considerably. Conclusion: The findings suggest that Bimanbang-1 causes weight loss and histological change, thus it may be effective to treat obesity.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1095-1099
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• 2006

Leptin and IGFBP-3 are two proteins that play an important role in growth and metabolism of the animals. They are also involved in the immune function of animals and, thus, are candidate genes for the study of association with immune functions. Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) of these two genes was done to screen 64 crossbred (Holstein Friesian${\times}$Hariana) female calves of one year of age. From each RFLPs (fragments) three genotypes were observed. In all the RFLPs the mutant homozygotes were very less in numbers and, hence, were excluded from the least squares analysis. The serum IgG level was estimated using SRID assay. The mean level of serum IgG was $28.83{\pm}2.73mg/ml$. The effect of these identified genotypes on serum IgG level of calves at one year of age was analysed using least squares analysis. The HaeIII RFLP-AB genotype had significantly (p<0.05) higher serum IgG level ($31.86{\pm}3.05$) than the HaeIII RFLP-AA ($25.62{\pm}2.96$) genotype. There was no significant effect of leptin genotypes on the IgG level. The present results indicated a role of the IGFBP-3 gene on serum IgG level of cattle calves.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1691-1695
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• 2006

The identification method that inflects real time ultrasound (RUT) and the potential application of marker assisted selection (MAS) for improvement of a cow population of Hanwoo (Korean Native cattle) was studied. The averages of RUT longissimus muscle area, RUT fat thickness, and RUT marbling score scanned at the 13th rib were 55.78 $cm^2$, 3.70 mm and 3.83 scores, respectively. We investigated the effects of the two SNPs (Kpn2 I and Msp I) in the leptin gene on carcass traits for Hanwoo cows by using ultrasound measurements. Genotype CC of the Kpn2 I had a significantly higher effect on back fat thickness (4.23 mm) and longissimus muscle area (57.57 $cm^2$) than genotype TT (3.14 mm, 53.93 $cm^2$, respectively, p<0.05). Genotype AA of the Msp I had a significantly higher effect only on marbling score (5.37) than genotype AB (3.57, p<0.05) and BB (3.37, p<0.05). Significant effects of SNPs in the leptin gene were found for the ultrasound measures of body composition in live cattle.