scholarly journals Synthesis of chain elongation-desaturation products of linoleic acid by liver and brain microsomes during development of the pig

1985 ◽  
Vol 226 (1) ◽  
pp. 305-309 ◽  
Author(s):  
M T Clandinin ◽  
K Wong ◽  
R R Hacker

Microsomes isolated from liver and brain tissue were assayed to examine transitions in metabolic capability to synthesize chain elongation-desaturation products of C18:2(9,12) during the perinatal development of the pig. Microsomal synthesis of trienes, tetraenes and pentaenes was compared for fetal, neonatal and postnatal piglets. Rates of synthesis of tetraenes and pentaenes by chain elongation-desaturation of C18:2(9,12) were greatest in liver. During the later half of gestation, the capability to synthesize tetraenes increased 2-3-fold on a per mg of microsomal protein basis. Increase in the capacity to synthesize tetraenes suggests a significant transition in the activity of delta 5 desaturase during the last half of gestation. For brain, synthesis of C22:5(4,7,10,13,16) from C18:2(9,12) was greatest at term. These observations indicate that in liver and brain the capability to chain elongate-desaturate C18:2(9,12) to longer chain homologues increases significantly during early development. It is suggested that during gestation the activity of the delta 5 desaturase limits synthesis of C20 and C22 homologues of C18:2(9,12). The metabolic conversion of C20 and C22 fatty acids by chain elongation of C20:4(5,8,11,14) does not appear to limit the synthesis of very long chain homologues of linoleic acid in fetal liver or brain.

1985 ◽  
Vol 227 (3) ◽  
pp. 1021-1023 ◽  
Author(s):  
M T Clandinin ◽  
K Wong ◽  
R R Hacker

Microsomes isolated from liver and brain tissue were assayed to examine transitions in metabolic capability to synthesize tetraenes and pentaenes by chain elongation-desaturation of C20:3(8,11,14) during the perinatal development of the pig. Rates of synthesis of tetraenes and pentaenes by chain elongation-desaturation of C20:3(8,11,14) were greatest in liver. During the latter half of gestation, the capability to synthesize tetraenes increased 7- or 23-fold on a per mg of microsomal protein basis for brain and liver respectively. Increase in the capacity to synthesize tetraenes from C20:3(8,11,14) suggests a significant transition in the activity of the delta 5-desaturase during the last half of gestation. These observations indicate that in liver and brain the capability to chain elongate-desaturate C18:2(9,12) to longer chain homologues increases significantly during early development as a function of transitions in the activity of the delta 5-desaturase.


1995 ◽  
Vol 269 (2) ◽  
pp. E247-E252 ◽  
Author(s):  
H. O. Ajie ◽  
M. J. Connor ◽  
W. N. Lee ◽  
S. Bassilian ◽  
E. A. Bergner ◽  
...  

To determine the contributions of preexisting fatty acid, de novo synthesis, and chain elongation in long-chain fatty acid (LCFA) synthesis, the synthesis of LCFAs, palmitate (16:0), stearate (18:0), arachidate (20:0), behenate (22:0), and lignocerate (24:0), in the epidermis, liver, and spinal cord was determined using deuterated water and mass isotopomer distribution analysis in hairless mice and Sprague-Dawley rats. Animals were given 4% deuterated water for 5 days or 8 wk in their drinking water. Blood was withdrawn at the end of these times for the determination of deuterium enrichment, and the animals were killed to isolate the various tissues for lipid extraction for the determination of the mass isotopomer distributions. The mass isotopomer distributions in LCFA were incompatible with synthesis from a single pool of primer. The synthesis of palmitate, stearate, arachidate, behenate, and lignocerate followed the expected biochemical pathways for the synthesis of LCFAs. On average, three deuterium atoms were incorporated for every addition of an acetyl unit. The isotopomer distribution resulting from chain elongation and de novo synthesis can be described by the linear combination of two binomial distributions. The proportions of preexisting, chain elongation, and de novo-synthesized fatty acids as a percentage of the total fatty acids were determined using multiple linear regression analysis. Fractional synthesis was found to vary, depending on the tissue type and the fatty acid, from 47 to 87%. A substantial fraction (24-40%) of the newly synthesized molecules was derived from chain elongation of unlabeled (recycled) palmitate.


2018 ◽  
Vol 61 (4) ◽  
pp. 395-403
Author(s):  
Milan Margetín ◽  
Marta Oravcová ◽  
Jana Margetínová ◽  
Róbert Kubinec

Abstract. The fatty acid (FA) composition in the intramuscular fat (IMF) of the musculus longissimus dorsi (MLD) of Ile de France purebred lambs in two different production systems in Slovakia was evaluated using gas chromatography. In the first production system, lambs and ewes were assigned to pasture without access to concentrates (P). In the second system, lambs and ewes were confined indoors with hay/silage and access to concentrates (S). An analysis of variance with the following factors was employed: production system, sex, and production system–sex interactions. The proportions of arachidonic, eicosapentaeonic, docosapentaeonic, and docosahexaenoic FAs, i.e. long-chain polyunsaturated FA (PUFA), were significantly higher in P lambs (1.83, 0.82, 0.92, 0.29 g 100 g−1 FAME, respectively) than in S lambs (0.45, 0.14, 0.30, 0.09 g 100 g−1 FAME, respectively). The proportions of conjugated linoleic acid (CLA), n-6 PUFA, n-3 PUFA, and essential FA (linoleic and α-linolenic) were also significantly higher in P lambs (2.10, 8.50, 4.55, and 8.80 g 100 g−1 FAME, respectively) than in S lambs (0.65, 3.27, 1.50, and 3.64 g 100 g−1 FAME, respectively). The proportions of palmitic acid and myristic acid as important individual saturated FAs (SFA) were significantly higher in S lambs (28.51 and 8.30 g 100 g−1 FAME, respectively) than in P lambs (21.80 and 5.63 g 100 g−1 FAME, respectively). The proportion of all SFAs was also significantly higher in S lambs (57.87 g 100 g−1 FAME) than in P lambs (48.70 g 100 g−1 FAME). From a nutrition and human health point of view (i.e. higher proportions of PUFA, CLA, and essential FAs and lower proportions of SFAs), meat from P lambs was found to be more favourable and would be more highly recommended for consumption.


2020 ◽  
pp. 1-26
Author(s):  
Yan Wang ◽  
Yiwei Tang ◽  
Ye Ji ◽  
Wenhui Xu ◽  
Naeem Ullah ◽  
...  

Abstract In this study, we analysed the effects of single nucleotide polymorphism (SNP) rs174547 (T/C) in the fatty acid desaturase 1 (FADS1) gene on long-chain polyunsaturated fatty acid levels. Four databases were searched to retrieve related literature with keywords such as fatty acid, SNP, FADS1, and rs174547. A meta-analysis of the data was performed using Stata12.0 software, including summary statistics, test for heterogeneity, evaluation of publication bias, subgroup analysis, and sensitivity analysis. The associations between rs174547 in FADS1 and seven types of fatty acids, and delta-5 (D5D) and delta-6 fatty acid desaturase (D6D) activity were assessed based on the pooled results from 11 manuscripts. A total of 3713 individuals (1529 TT and 2184 TC+CC) were included. The results demonstrated that minor C allele carriers of rs174547 had higher linoleic acid (LA; P < 0.001) and α-linolenic acid (P = 0.020) levels, lower gamma linoleic acid (GLA; P = 0.001) and arachidonic acid (P = 0.024) levels, and lower D5D (P = 0.005) and D6D (P = 0.004) activities than the TT genotype group. Stratification analysis showed that minor C allele carriers of rs174547 had higher LA and lower GLA levels and lower D6D activities in plasma (LA, P < 0.001; GLA, P < 0.001; D6D activity, P < 0.001) samples and in Asian populations (LA, P < 0.001; GLA, P = 0.001; D6D activity, P = 0.001) than the TT genotype group. In conclusion, minor C allele carriers of the SNP rs174547 were associated with decreased activity of D5D and D6D.


1993 ◽  
Vol 291 (3) ◽  
pp. 841-845 ◽  
Author(s):  
J Naval ◽  
M J Martínez-Lorenzo ◽  
I Marzo ◽  
P Desportes ◽  
A Piñeiro

K562 human leukaemia cells lack a significant delta 6-desaturase activity. However, they synthesize long-chain polyunsaturated fatty acids (PUFA) from linoleic (C18:2(9,12)) and linolenic (C18:3(9,12,15)) acids, by reactions involving a C2 chain elongation followed by a delta 5-desaturation step and, to some extent, a further elongation. The main products formed were separated by argentation t.l.c. and identified by g.l.c. as the uncommon fatty acids C20:3(5,11,14) and C20:4(5,11,14,17) respectively. These acids were also produced when cells were supplemented with C20:2(11,14) or C20:3(11,14,17) respectively. The presence of a delta 5-desaturase was further confirmed by using its corresponding normal substrates, C20:3(8,11,14) and C20:4(8,11,14,17), which led to C20:4(5,8,11,14) and C20:5(5,8,11,14,17) respectively. On the other hand, a high delta 9-desaturase activity, but no significant delta 4-desaturase activity, were detected in K562 cells. These results indicate the existence of an alternative pathway, involving delta 5-desaturase, which is the only route for PUFA biosynthesis in K562 cells. This pathway may be relevant for the biosynthesis of PUFA in cells lacking delta 6-desaturase activity.


1980 ◽  
Vol 239 (3) ◽  
pp. G141-G150 ◽  
Author(s):  
G. B. McDonald ◽  
D. R. Saunders ◽  
M. Weidman ◽  
L. Fisher

We studied the route of transport of long-chain fatty acids (LCFA) from the rat intestine. Lauric (12:0), myristic (14:0), palmitic (16:0), stearic (18:0), linoleic (18:2), and linolenic (18:3) acids were infused intraduodenally for 4 h as micellar solutions into unanesthetized thoracic duct-fistula rats. Proportionally more of each LCFA was transported by the portal vein at infusion rates of 0.3 mumol/h than at 15 mumol/h. Of the LCFA absorbed at low rates of infusion, 72% of lauric, 58% of myristic, 41% of palmitic, 28% of stearic, 58% of linoleic, and 68% of linolenic acid bypassed the lymphatic pathway. To test the inference that 58% of absorbed linoleate was transported by the portal vein, [14C]linoleic acid was infused at 0.3 or 15 mumol/h into unanesthetized rats equipped with both thoracic duct and portal venous fistulas. Portal venous blood (0.1 ml) was withdrawn every 30 min for 4 h. Proportionally more [14C]linoleate was recovered in portal blood at the low infusion rate. To examine the morphology of fat absorption, segments of rat jejunum in anesthetized rats were infused with micellar linoleic acid at 3 or 150 mumol/h. At 3-mumol/h infusion rate, an appearance identical to the fasting state was seen by electron microscopy. At 150 mumol/h, many larger chylomicron-sized particles appeared in absorptive cells, intercellular spaces, and lymphatics. We conclude that a substantial proportion of unsaturated LCFA is transported from rat intestine in portal venous blood.


2008 ◽  
Vol 74 (14) ◽  
pp. 4292-4299 ◽  
Author(s):  
Sofia Windstam ◽  
Eric B. Nelson

ABSTRACT The aim of this study was to determine the temporal release of fatty acids and sugars from corn and cucumber seeds during the early stages of seed germination in order to establish whether sugars found in exudate can prevent exudate fatty acid degradation by Enterobacter cloacae. Both saturated (long-chain saturated fatty acids [LCSFA]) and unsaturated (long-chain unsaturated fatty acids [LCUFA]) fatty acids were detected in corn and cucumber seed exudates within 15 min after seed sowing. LCSFA and LCUFA were released at a rate of 26.1 and 6.44 ng/min/seed by corn and cucumber seeds, respectively. The unsaturated portion of the total fatty acid pool from both plant species contained primarily oleic and linoleic acids, and these fatty acids were released at a combined rate of 6.6 and 0.67 ng/min/seed from corn and cucumber, respectively. In the absence of seed exudate sugars, E. cloacae degraded linoleic acid at rates of 29 to 39 ng/min, exceeding the rate of total fatty acid release from seeds. Sugars constituted a significant percentage of corn seed exudate, accounting for 41% of the total dry seed weight. Only 5% of cucumber seed exudate was comprised of sugars. Glucose, fructose, and sucrose were the most abundant sugars present in seed exudate from both plant species. Corn seeds released a total of 137 μg/seed of these three sugars within 30 min of sowing, whereas cucumber seeds released 0.83 μg/seed within the same time frame. Levels of glucose, fructose, and sucrose found in corn seed exudate (90 to 342 μg) reduced the rate of linoleic acid degradation by E. cloacae to 7.5 to 8.8 ng/min in the presence of either sugar, leaving sufficient concentrations of linoleic acid to activate Pythium ultimum sporangia Our results demonstrate that elevated levels of sugars in the corn spermosphere can prevent the degradation of LCUFA by E. cloacae, leading to its failure to suppress P. ultimum sporangial activation, germination, and subsequent disease development.


Sign in / Sign up

Export Citation Format

Share Document