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Stearic acid unlike shorter‐chain saturated fatty acids is poorly utilized for triacylglycerol synthesis and β‐oxidation in cultured rat hepatocytes
Author(s) -
Pai Tonkun,
Yeh YuYan
Publication year - 1996
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02522615
Subject(s) - stearate , stearic acid , chemistry , fatty acid , biochemistry , diacylglycerol kinase , chromatography , organic chemistry , enzyme , protein kinase c
Abstract Utilization of stearate as compared to various saturated fatty acids for cholesterol and lipid synthesis and β‐oxidation was determined in primary culture of rat hepatocytes. At 0.5 mmol/L in the medium, stearate (18:0) adequately solubilized by albumin was less inhibitory to cholesterol synthesis from [2‐ 14 C] acetate than myristate (14:0) and palmitate (16:0) (68% vs. 91 and 88% inhibition, respectively). The rate of incorporation into cholesterol from [1‐ 14 C] stearate (3.0±0.6 nmol/mg protein/4 h) was 37‐, 1.8‐, and 7.8‐fold of that from myristate, palmitate, and oleate, respectively. Conversely, the rate of [1‐ 14 C] stearate incorporation into total glycerolipids was 88–90% lower than that of labeled palmitate, myristate, and oleate. The rate of [1‐ 14 C] stearate incorporation into triacylglycerol (3.6±0.4 nmol/mg protein/4 h) was 6–8% of that from myristate, palmitate, oleate, and linoleate. The rate of stearate incorporation into phospholipids was the lowest among tested fatty acids, whereas the rate of mono‐ and diacylglycerol synthesis was the highest with stearate treatment. The rate of β‐oxidation as measured by CO 2 and acid soluble metabolite production was also the lowest with [1‐ 14 C] stearate treatment at 22.7 nmol/mg protein/4 h, which was 35–40% of those from other [1‐ 14 C] labeled fatty acids. A greater proportion of stearate than other fatty acids taken up by the hepatocytes remained free and was not metabolized. Clearly, stearate as compared to shorter‐chain saturated fatty acids was less efficiently oxidized and esterified to triacylglycerol in cultured rat hepatocytes.