• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1548-1551
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• 2005

The leptin, an anti-obesity protein, is a hormone protein expressed and secreted mainly from adipocyte tissue, and involved in regulation of body weight, food intake and energy metabolism. In an effort to discover polymorphism(s) in genes whose variant(s) might be implicated in phenotypic traits of growth, we have sequenced exons and their boundaries of leptin gene including 1,000 bp upstream of promoter region with twenty-four unrelated Korean cattle. Fifty-seven sequence variants were identified: fourteen in 5' flanking region, twenty-seven in introns, eight in exons, and eight in 3' flanking region. By pair-wise linkage analysis among polymorphisms, ten sets of SNPs were in absolute linkage disequilibrium (LD) (|D'| = 1 and $r^2$ = 1). Among variants identified, thirty-six SNPs were newly identified, and twenty-one SNPs, which were reported in other breeds, were also confirmed in Korean cattle. The allele frequencies of variants were quite different among breeds. The information from SNPs of bovine leptin gene could be useful for further genetic studies of this gene.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1589-1593
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• 2005

The aim of this study was to investigate the effects of testosterone, 17$\beta$-estradiol, and progesterone on the differentiation of bovine intramuscular adipocytes (BIA). Stromal-vascular (SV) cells were obtained from M. longissimus dorsi of 20 months old Korean (Hanwoo) steers, and were cultured in DMEM containing 5% FBS. The proliferated BIA were induced to differentiate with 0.25 $\mu$M dexamethasone, 0.5 mM 1-methyl-3-isobutyl-xanthine and 10 $\mu$g/ml insulin. During differentiation, the cells were treated with testosterone, 17$\beta$-estradiol, and progesterone at concentrations of $10^{-10}$, $10^{-9}$, and $10^{-8}$ M, respectively, for 12 days. Regardless of its concentration, testosterone remarkably reduced lipid droplets in the cytosol of BIA. On the other hand, 17$\beta$-estradiol and progesterone increased the accumulation of lipid droplets in BIA. Testosterone significantly (p<0.05) decreased GPDH activities with a dose-dependent pattern. 17$\beta$-Estradiol treatment onto BIA during differentiation, however, increased GPDH activity showing the highest activity (11.3 nmol/mg protein/min) at $10^{-10}$ M. Treatment of BIA with progesterone also increased (p<0.05) GPDH activity with the highest activity (13.8 nmol/mg protein/min) at $10^{-9}$ M. In conclusion, the results in the current study suggest that testosterone inhibits differentiation of BIA by suppressing GPDH activity while 17$\beta$-estradiol and progesterone have adverse effects.

• BMB Reports
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• v.31 no.6
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• pp.542-547
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• 1998

The main function of adipocytes in various species is to store nutrient energy in the form of triglycerides, and this function may he closely related with hormonal signaling through the plasma membrane of adipocytes. Using SDS-PAGE, two-dimensional gel electrophoresis, and a membrane biotinylation technique, we have identified a 55KDa protein (55K protein) from the plasma membrane fraction of adipocytes, with an isoelectric point (pI) of 8.1-8.3. However, this 55K protein was not observed with a two-dimensional gel electrophoresis carried out on plasma membrane fractions prepared from the liver, heart, and kidney tissues. An analysis of the 12 amino acids sequence at the N-terminal of the 55K protein showed that it has a similar sequence to that of bovine serum albumin.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.715-723
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• 2018

The present study was done to investigate the effect of co-culturing muscle satellite cells (MSCs) and intramuscular preadipocytes (IPs) on the differentiation of adipocytes and muscle cells isolated from Korean native cattle. MSCs and IPs were single-cultured in 10% fetal bovine serum/Dulbecco's modified Eagles medium (FBS/DMEM) for 48 h followed by culturing in 5% FBS/DMEM as the growth media. Then, the growth media was replaced by differentiation media composed of 2% FBS/DMEM without any additives for the single- or co-culture of muscle cells and intramuscular adipocytes to induce the differentiation of both cell types. Cell differentiation was measured by morphological investigation and cytosolic enzyme analysis of glycerol-3-phosphate dehydrogenase (GPDH) for the adipocytes and creatine kinase (CK) for the muscle cells. In the morphological test, the presence of muscle cells did not stimulate adipocyte differentiation showing more differentiation of the adipocytes in the single-culture compared to the co-culture condition. However, the differentiation of muscle cells was promoted by adipocytes in the co-culture. The results of the enzymatic analysis were highly associated with the morphological results with a statistically higher GPDH activity (p < 0.05) appearing in the single-culture than in the co-culture, whereas the opposite was true for the CK activity of the muscle cells (p < 0.05). By manipulating in vivo the milieu using a co-culture, we could detect the difference in the rate of cell differentiation and suggest that a co-culture system is a more reliable and precise technique compared to a single-culture. Further studies on various co-culture trials including supplementation of differentiating substances, gene expression analysis, etc. should be done to obtain practical and fundamental data.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1173-1183
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• 2022

Adipogenesis is a complex process comprising commitment and a differentiation stages. Through research, many different transcriptional factors were found to mediate preadipocyte commitment and differentiation. Lysine has a potential of regulating the commitment and differentiation of preadipocytes. In the present study, intramuscular stromal vascular cells (SVC) isolated from Hanwoo beef cattle were used to elucidate the effects of low lysine level on adipogenesis. SVC were isolated and incubated with various concentrations of lysine (0, 37.5, 75, 150 and 300 µg/mL). No significant difference were observed in the proliferation of SVC after 24 and 48 h of incubation with different concentration of lysine. On preadipocyte determination, reducing the level of lysine significantly increased the expression of preadipocyte commitment gene Zinc finger protein 423 and Preadipocyte factor-1. Upon differentiation, Oil Red O staining revealed that lipid accumulation and triglyceride content significantly increased with the decreasing lysine levels in the media. Expression levels of peroxisome proliferator-activated receptor-γ, CCAAT enhancer binding protein-α, sterol regulatory element binding protein-1c, Fatty Acid Binding Protein 4 and stearoyl CoA desaturase were upregulated by the decreased level of lysine. These data suggest the potential mechanism of action for the improved preadipocyte commitment and adipocyte differentiation in bovine intramuscular SVC upon treatment with low levels of lysine. These findings may be valuable in developing feed rations that promote deposition of intramuscular fat in beef cattle through lysine level modification.

• Molecules and Cells
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• v.22 no.2
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• pp.239-245
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• 2006

This study examined whether adult bovine muscle satellite cells from 30-month-old Hanwoo cattle are multipotential. The satellite cells were found to have the potential to proliferate and differentiate into myoblasts with the formation of multinucleated cells. In addition, treatment with the peroxisome proliferator activating receptor-${\gamma}$ ($PPAR{\gamma}$) agonist, rosiglitazone, promoted their trans-differentiation into adipocytes with significant increases in glycerol accumulation and glycerol-3-phosphate dehydrogenase activity. Western blot analysis revealed that increased levels of the adipocyte fatty acid-binding protein, $PPAR{\gamma}$ and of CCAAT/enhancerbinding protein were closely related to rosiglitazoneinduced differentiation of the cells. These findings demonstrate that satellite cells from adult Hanwoo cattle are multipotent, and that their trans-differentiation into adipocytes can be induced by rosiglitazone.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.1
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• pp.58-62
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• 2019

Objective: The oxidized low density lipoprotein receptor 1 (OLR1) gene plays an important role in the degradation of oxidized low-density lipoprotein and adipocyte proliferation in mammals. For this reason, we aimed at investigating the association of OLR1 gene polymorphisms with carcass quality traits in Chinese Qinchuan cattle. Methods: The single nucleotide polymorphism (SNP) was identified in the 3' untranslated region of bovine OLR1 gene by DNA sequencing. In addition, the haplotype frequency and linkage disequilibrium estimates of three SNPs were evaluated in 520 individuals. Results: Results indicated that the studied three SNPs were within the range of moderate genetic diversity (0.25< polymorphism information content<0.5). Haplotype analysis of three SNPs showed that ten different haplotypes were identified, but only five haplotypes were listed as those with a frequency of <0.05 were excluded. The Hap3 ($-G_1T_2C_3-$) had the highest haplotype frequency (42.10%). Linkage disequilibrium analysis showed that the three SNPs had a low linkage ($r^2<0.001$). The T10588C and C10647T were significantly associated with backfat thickness and intramuscular fat content in Qinchuan cattle. Conclusion: Based on our results, we believe that the OLR1 gene could be a strong candidate gene for influencing carcass quality traits in Qinchuan cattle.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1087-1094
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• 2005

The uptake of glucose for metabolism and growth is essential to most animal cells and is mediated by glucose transport protein. In the glucose transport protein family, GLUT4 plays a key role in cellular glucose uptake stimulated by insulin in skeletal muscles and adipose tissue in rodents and human. In this studies, we reported the identification, characterization, and expression of Hanwoo GLUT4 gene. The Hanwoo GLUT4 cDNA includes a 1527 bp open reading frame encoding a protein of 509 amino acids. The GLUT4 amino acid sequences of the Hanwoo show strong conservation with the corresponding sequences reported in other species. The highest mRNA expression of GLUT4 was detected in heart and lower expression was detected in rib meat, sirloin, and colon. We confirmed the expression of GLUT4 in the subcutaneous and small intestinal adipose tissue using RT-PCR. To investigate the expression of GLUT4 in the bovine intramuscular adipose differentiation, fibroblast-like cells were isolated from the sirloin of Hanwoo bull aged 12 months by collagenase digestion of minced tissue and cultured with activators of PPAR gamma. We identified that GLUT4 mRNA expression decreased during differentiation of preadipocytes into adipocyte in Korean cattle. These results indicated that function of GLUT4 in bovine adipose tissue was different from that of mouse and human.

• Journal of Animal Science and Technology
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• v.54 no.2
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• pp.103-109
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• 2012

Present study was performed to investigate the effect of single and co-culture of adipocyte and muscle cell lines on cell differentiation. 3T3-L1 (adipocyte) and L6 (muscle) cell lines were single-cultured on the condition of 10% fetal bovine serum (FBS)/Dulbeco's modified eagle's medium (DMEM) for 48 h followed by culture within 5% FBS/DMEM as a growth media. Then, the growth media was replaced by differentiation media composed of 2% FBS/DMEM without additives in single- or co-culture of the 3T3-L1 and the L6 cells to induce differentiation of both cell types. In co-culture system, the 3T3-L1 and the L6 cells were grown in separated places by being seeded on a $0.4{\mu}m$ insert membrane and on the bottom of 6 well plate, respectively. Cell differentiation was measured using morphological investigation and cytosolic analysis of glycerol-3-phosphate dehydrogenase (GPDH; for 3T3-L1) and creatine kinase (CK; for L6). Based on the GPDH results, the presence of L6 cells did not stimulate 3T3-L1 differentiation showing more differentiation of 3T3-L1 cells in the single-culture compared to the co-culture condition. In contrast, 3T3-L1 cells in the co-culture promoted differentiation of L6 cells. Enzymatic analysis supported this result showing that 3T3-L1 cells showed statistically (P<0.05) higher GPDH activity in the single-culture than the co-culture, whereas CK results of L6 cells were vice versa (P<0.05). Overall, present results may indicate that co-culture system is more reliable and precise technique compared to single-culture. Further studies on several co-culture trials including different media conditions, supplementation of differentiating substances, molecular biological analysis, etc. should be required to obtain practical and fundamental mass data.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.913-918
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• 2005

The development of marbling in cattle is closely associated with an increase in adipocyte size and number within muscle. The adipose precursor cells have the capacity to differentiate into adipocytes within the muscle during the formation of marbling. In this studies, we established the cell culture system for differentiation of intramuscular preadipocyte isolated from the sirloin of Hanwoo aged 12 months. The intramuscular preadipocyte cells exhibited a fibroblastic appearance and differentiated into adipocytes by treating confluent cells with differentiation medium containing insulin, dexamethasone, and troglitazone. When intramuscular preadipocyte cells were differentiated at 18 day, the triglyceride concentration was higher than control cells. Moreover, the thiazolidinedione treatment increased adipogenesis. RT-PCR analysis confirmed the significant expression of PPARγ mRNA during adipocyte differentiation. In conclution, our culture system used in this study allowed intramuscular preadipocyte cells to differentiated into adipocytes and intramuscular preadipocyte cells may be useful in the further study of differentiation mechanism of adipocytes in Hanwoo.