Quantitative HPLC analysis of the level of fecapentaenes and their precursors in human feces by a chemical conversion method.

A fast and reliable hplc method for the quantitative analysis of total fecapentaene-12 (FP-12 and its precursors) and total fecapentaene-14 (FP-14 and its precursors) in human feces is described. The analysis is based on the rapid chemical conversion of fecapentaenes and their precursors to more stable methoxytetraenols and the use of synthetic, not naturally occurring, fecapentaene-13 (FP-13) as an internal standard. The synthesis and physical properties of this internal standard are described.

Evaluation of jojoba oil as a low-energy fat. 2. Intestinal transit time, stomach emptying and digestibility in short-term feeding studies in rats.

The influence of jojoba oil (JO) incorporation in the diet on stomach emptying and intestinal transit time, and the digestion and absorption of JO were investigated in short-term feeding studies in rats. The animals were fed purified diets containing 18% (w/w) fat, of which half consisted of a mixture of lard and sunflower seed oil (SF) supplemented with an equivalent amount of JO. The control animals were fed a mixture of lard and SF (18%).

Lipid composition of cultured human keratinocytes in relation to their differentiation.

The present study was undertaken to explore the possibility of the use of cultured human keratinocytes for the study of changes in lipid composition in relation to epidermal differentiation. In a submerged culture system, in which the stratification is incomplete, no significant differences have been found between the lipid composition of cells grown either at low calcium concentration (0.06 mM) (at which the keratinocyte differentiation is markedly retarded) or at normal calcium concentration (1.

The urinary excretion of prostaglandins E and their corresponding tetranor metabolites by rats fed a diet rich in eicosapentaenoate.

An HPLC method was developed to determine simultaneously in a single analysis prostaglandin E2, prostaglandin E3, tetranor-prostaglandin E1 and delta 17-tetranor-prostaglandin E1 in rat urine. As internal standard omega-nor-prostaglandin E2 was added to the samples at the beginning of the analysis. The assay was applied in feeding experiments in which rats were fed diets with mixtures of (n-6) and (n-3) fatty acids (linoleate, arachidonate, alpha-linolenate and eicosapentaenoate).

Conversion of linoleic acid and arachidonic acid by skin epidermal lipoxygenases.

Two different lipoxygenases have been identified in human and rat epidermis. One lipoxygenase has a (n-9)-specificity, converts arachidonic acid into 12-hydroxyeicosatetraenoic acid (12-HETE), and has been described by several investigators. Linoleic acid is not a substrate for this enzyme.