<i>IN VITRO</i> FORMATION OF POLYUNSATURATED FATTY ACIDS BY DESATURATION IN RAT BRAIN: SOME PROPERTIES OF THE ENZYMES IN DEVELOPING BRAIN AND COMPARISONS WITH LIVER<sup>1</sup>

Cook, Harold W.

doi:10.1111/j.1471-4159.1978.tb10463.x

Cited by 123 publications

(52 citation statements)

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“…It has been suggested that the brain receives much of its complement of DHA "preformed" from the circulation via the liver (33,34), although the rat brain, and especially the developing rat brain, has a substantial capacity for the synthesis of DHA from precursor molecules (35,36). Our results showed that DHA was formed from dietary EPA and accumulated in the brain to nearly the same extent as the DHA when fed directly in the diet.…”

mentioning

confidence: 46%

Docosahexaenoic Acid Is the Preferred Dietary n-3 Fatty Acid for the Development of the Brain and Retina

1990

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ABSTRACT. The metabolism of individual dietary n-3 fatty acids was studied in n-3 fatty acid-deficient newly hatched chicks. Laying hens were fed the n-6 fatty acid, ethyl linoleate, as the only source of polyunsaturated fat. Chicks were then fed the n-3-deficient hens' diet, or one of three other diets supplemented with the ethyl ester of 18:3n-3, 20:5n-3 [eicosapentaenoic acid (EPA)], or 22:6n-3 [docosahexaenoic acid (DHA)] at 0.44% of calories. At the end of 0, 1, 2, and 3 wk, the fatty acid composition of the brain, retina, liver, and serum was determined. Dietary EPA and DHA were equally effective at raising levels of DHA in the brain and retina. Dietary 18:3 was relatively ineffective in restoring brain and retina DHA. In the n-3-deficient chicks fed EPA or DHA, levels of DHA recovered to control values in both the brain and retina by 3 wk. Very little EPA accumulated in the brain or retina of chicks fed EPA. Hepatic synthesis of DHA from EPA appeared low, suggesting that the brain and retina synthesized the DHA that accumulated rapidly in these tissues after the feeding of EPA. The 6-4-desaturase enzyme was apparently very active, then, in the brain and retina. Retroconversion of dietary 22:6 to 22:5 and 20:5 was evident in the serum, liver, and retina but not in the brain. Thus, it was possible to study the relative metabolism and especially the interconversion of n-3 fatty acids in a environment uncomplicated by existing stores of these essential fatty acids. This study would suggest that 18:3 as the sole source of n-3 fatty acids in the diets of animals, including the human infant, may not be adequate for the biochemical development of the brain and retina and that dietary DHA is the preferred fatty acid of the n-3 series. (Pediatr Res 27: 89-97, 1990) Abbreviations DHA, docosahexaenoic acid EPA, eicosapentaenoic acid The n-3 family of polyunsaturated fatty acids has become the focus of much interest because of evidence that these compounds

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confidence: 46%

Docosahexaenoic Acid Is the Preferred Dietary n-3 Fatty Acid for the Development of the Brain and Retina

1990

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“…In vitro preparation from brain and liver (Cook, 1978) showed that in the very young 10-day-old rats, conversion of 18:2n-6 and 18:3n-3 by A6-desaturation was much higher in brain than in liver. The A5-desaturation of 20:3n-6, although very low in brain, was also significantly higher than in liver.…”

Section: Dietary Sources Of Essential Fatty Acidsmentioning

confidence: 96%

The metabolism and availability of essential fatty acids in animal and human tissues

Bézard

Blond²,

Bernard³

et al. 1994

Reprod. Nutr. Dev.

191

109

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Summary ― Essential fatty acids (EFA), which are not synthesized in animal and human tissues, belong to the n-6 and n-3 families of polyunsaturated fatty acids (PUFA), derived from linoleic acid (LA,) and a-linolenic acid (LNA,. Optimal requirements are 3-6% of ingested energy for LA and 0.5-1% for LNA in adults. Requirements in LNA are higher in development. Dietary sources of LA and LNA are principally plants, while arachidonic acid (AA,) is found in products from terrestrian animals, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)

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“…Metabolic activity reflecting EFA elongation and desaturation in human subjects is found mainly in the liver, but also in the placenta, central nervous system, glial tissue and choroid plexus vasculature (Bourre et al 1997;Cook, 1978). Whole-body elongase and desaturase activity can be assessed in vivo using either 2 H-or 13 C-labelled EFA substrates, enabling the evaluation of product formation in plasma and tissue compartments.…”

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Essential fatty acids in early life: structural and functional role

2000

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Essential fatty acids (EFA) are structural components of all tissues and are indispensable for cell membrane synthesis; the brain, retina and other neural tissues are particularly rich in long-chain polyunsaturated fatty acids (LCPUFA). These fatty acids serve as specific precursors for eicosanoids that regulate numerous cell and organ functions. Results from animal and recent human studies support the essential nature of n-3 EFA in addition to the well-established role of n-6 EFA for human subjects, particularly in early life. The most significant effects relate to neural development and maturation of sensory systems. Recent studies using stable-isotope-labelled tracers demonstrate that even preterm infants are able to form arachidonic acid (AA) and docosahexaenoic acid (DHA), but that synthesis is extremely low. Intracellular fatty acids or their metabolites regulate transcriptional activation of gene expression during adipocyte differentiation, and retinal and nervous system development. Regulation of gene expression by LCPUFA occurs at the transcriptional level and is mediated by nuclear transcription factors activated by fatty acids. These nuclear receptors are part of the steroid hormone receptor family. Two types of polyunsaturated fatty acid responsive transcription factors have been characterized, the peroxisome proliferator-activated receptor (PPAR) and the hepatic nuclear factor 4α. DHA also has significant effects on photoreceptor membranes involved in the signal transduction process, rhodopsin activation, and rod and cone development. Comprehensive clinical studies have shown that dietary supplementation with marine oil or single-cell oils, sources of LCPUFA, results in increased blood levels of DHA and AA, as well as an associated improvement in visual function in formula-fed premature infants to match that of human milk-fed infant. Recent clinical trials convincingly support LCPUFA supplementation of preterm infant formulations and possibly term formula to mimic human milk composition.

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IN VITRO FORMATION OF POLYUNSATURATED FATTY ACIDS BY DESATURATION IN RAT BRAIN: SOME PROPERTIES OF THE ENZYMES IN DEVELOPING BRAIN AND COMPARISONS WITH LIVER¹

Cited by 123 publications

References 21 publications

Docosahexaenoic Acid Is the Preferred Dietary n-3 Fatty Acid for the Development of the Brain and Retina

Docosahexaenoic Acid Is the Preferred Dietary n-3 Fatty Acid for the Development of the Brain and Retina

The metabolism and availability of essential fatty acids in animal and human tissues

Essential fatty acids in early life: structural and functional role

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IN VITRO FORMATION OF POLYUNSATURATED FATTY ACIDS BY DESATURATION IN RAT BRAIN: SOME PROPERTIES OF THE ENZYMES IN DEVELOPING BRAIN AND COMPARISONS WITH LIVER1

Cited by 123 publications

References 21 publications

Docosahexaenoic Acid Is the Preferred Dietary n-3 Fatty Acid for the Development of the Brain and Retina

Docosahexaenoic Acid Is the Preferred Dietary n-3 Fatty Acid for the Development of the Brain and Retina

The metabolism and availability of essential fatty acids in animal and human tissues

Essential fatty acids in early life: structural and functional role

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Product

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IN VITRO FORMATION OF POLYUNSATURATED FATTY ACIDS BY DESATURATION IN RAT BRAIN: SOME PROPERTIES OF THE ENZYMES IN DEVELOPING BRAIN AND COMPARISONS WITH LIVER¹