Conversion of linoleic acid into arachidonic acid by cultured murine and human keratinocytes.
Conversion of linoleic acid into arachidonic acid by cultured murine and human keratinocytes.
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通过培养的鼠和人角质形成细胞将亚油酸转化为花生四烯酸。
DOI：
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发表时间：
1987
影响因子：
6.5
通讯作者：
D. Martinez
中科院分区：
文献类型：
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作者：
R. Isseroff;V. Ziboh;R. Chapkin;D. Martinez
花生四烯酸（AA）在表皮中发现的来源尚不清楚。存在两种可能性：表皮角化细胞内的新合成，或在远处组织部位形成的AA的运输。目前的研究检测了培养的小鼠和人角质形成细胞代谢外源性添加的亚油酸（LA）的能力。注意到放射性标记的底物（14C-LA）转化为18:3(n-6), 20:2(n-6), 20:3（n-6）和20:4(n-6) （AA）。对非放射性标记的18:3（n-6）或20:2（n-6）的转化也进行了研究，合成的代谢物模式表明，亚油酸转化为花生四烯酸的首选代谢途径是通过经典描述的途径，其中δ 6去饱和酶构成初始反应。虽然已知培养的皮肤成纤维细胞可以将亚油酸转化为花生四烯酸，但目前的研究表明，培养的表皮角质形成细胞也可以大量代谢外源性亚油酸。体外培养的角质形成细胞，而不是体内的整个表皮细胞，将亚油酸转化为花生四烯酸的能力表明，特定的酶活性可能是由组织培养系统本身诱导的。因此，培养细胞代谢能力的发现不一定能推断到体内情况。
The origin of arachidonic acid (AA) found in the epidermis is not known. Two possibilities exist: either de novo synthesis within the epidermal keratinocyte, or transport of AA formed at distant tissue sites. The current study examined the ability of cultured murine and human keratinocytes to metabolize exogenously added linoleic acid (LA). Conversion of radiolabeled substrate (14C-LA) into 18:3(n-6), 20:2(n-6), 20:3(n-6), and 20:4(n-6) (AA) was noted. The conversion of non-radiolabeled 18:3(n-6) or 20:2(n-6) was also examined and the pattern of metabolites synthesized suggests that the preferred metabolic pathway for conversion of linoleic acid into arachidonic acid is via the classically described pathway in which a delta 6 desaturase constitutes the initial reaction. Although cultured skin fibroblasts are known to convert linoleic acid into arachidonic acid, the current study demonstrates that cultured epidermal keratinocytes can also avidly metabolize exogenous linoleic acid. The ability of cultured keratinocytes, and not of whole epidermis in vivo, to convert linoleic acid into arachidonic acid suggests that specific enzymatic activities may be induced by the tissue culture system itself. Hence, findings of metabolic capabilities in cultured cells may not necessarily be extrapolated to the in vivo situation.