Intramuscular adipose tissue had greater levels of both GPR43 protein and mRNA as compared to subcutaneous adipose tissue. These data point to a potential difference between the two fat stores that could be exploited to enhance marbling without increasing carcass backfat in beef cattle. Additionally, GPR43 mRNA and protein levels in intramuscular (IM) preadipocytes were regulated in a dose-dependent fashion with oleic acid treatment while the subcutaneous (SC) preadipocytes were not. Data also indicated that three different bovine primary cell cultures (bovine muscle satellite cells, IM preadipoctyes and SC preadipoctyes) are differentially affected by the dose-dependent treatment with oleic acid. Western blot analysis illustrated that a greater (P < 0.05) amount of oleic acid enhanced the GPR43 to GAPDH protein ratio in IM adipocytes but did not affect (P > 0.10) SC adipocytes. The mRNA level of GPR43 tended to increase (P = 0.098) with dose titration of the IM adipocytes but did not affect (P > 0.10) SC adipocytes. This data demonstrated that oleic acid may have autocrine or paracrine effects in stimulating marbling development but SC adipose development may be differentially regulated. Interestingly, oleic acid increased (P < 0.05) GPR43 mRNA level in the BSC. This data indicated that dose dependent treatment of oleic acid enhanced IM adipocyte development and appeared to have similar effects on cultured muscle satellite cells. Therefore, researchers concluded oleic acid may be a critical factor to enhance GPR43 pathway in the bovine IM adipose tissues.
Relative GPR43 mRNA level was greater expressed in intramuscular (IM) adipose tissue than subcutaneous (SC) adipose tissue and muscle (MUS) tissues. The protein level of GPR43 per GAPDH was greater in IM adipose tissue than in SC adipose tissue. All Analysis was triplicate. abTissues with different superscripts differ (P < 0.05)
A. Oleic acid increased dose dependent level of GPR43 per GAPDH protein in the intramuscular (IM) adipocyte compare to subcutaneous (SC) adipocyte. Bars are means ± SE relative to control. abcde within cell culture, treatments differ (P < 0.05). Values are the means of 3 replicates.
B. Oleic acid tended to be increased relative GPR43 mRNA level in the intramuscular adipocyte compare to subcutaneous adipocyte. Values are the means of 3 replicates.