scholarly journals Effect of Exogenous Long-Chain Fatty Acids on Individual Fatty Acid Synthesis by Dispersed Ruminant Mammary Gland Cells

1987 ◽  
Vol 70 (7) ◽  
pp. 1350-1354 ◽  
Author(s):  
Hans Otto Hansen ◽  
Jens Knudsen
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Individual Fatty Acid ◽  
Long Chain Fatty Acids ◽  
Gland Cells ◽  
Mammary Gland Cells ◽  
Long Chain

scholarly journals Interactions of insulin, corticosterone and prolactin in promoting milk-fat synthesis by mammary explants from pregnant rabbits

1972 ◽  
Vol 129 (4) ◽  
pp. 929-935 ◽  
Author(s):  
Isabel A. Forsyth ◽  
Christopher R. Strong ◽  
Raymond Dils
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Long Chain Fatty Acids ◽  
Medium Chain ◽  
Long Chain ◽  
Chain Fatty Acids

1. The rate of fatty acid synthesis by mammary explants from rabbits pregnant for 16 days or from rabbits pseudopregnant for 11 days was stimulated up to 15-fold by culturing for 2–4 days with prolactin. This treatment initiated the predominant synthesis of C8:0 and C10:0 fatty acids, which are characteristic of rabbit milk. 2. Inclusion of insulin in the culture medium increased the rate of synthesis of these medium-chain fatty acids. By contrast the inclusion of corticosterone led to the predominant synthesis of long-chain fatty acids. When explants were cultured for 2–4 days with insulin, corticosterone and prolactin, the rate of fatty acid synthesis increased up to 42-fold, but both medium- and long-chain fatty acids were synthesized. 3. These results show that the stimulus to mammary-gland lipogenesis and the initiation of synthesis of medium-chain fatty acids observed between days 16 and 23 of pregnancy in the rabbit can be simulated in vitro by prolactin alone. 4. When mammary explants from rabbits pregnant for 23 days were cultured for 2 days with insulin, corticosterone and prolactin, the rate of fatty acid synthesis increased fivefold, but there was a preferential synthesis of long-chain fatty acids. Culture with prolactin alone had little effect on the rate or pattern of fatty acids synthesized. 5. The results are compared with findings in vivo on the control of lipogenesis in the rabbit mammary gland, and are contrasted with the known effects of hormones in vitro on the mammary gland of the mid-pregnant mouse.

scholarly journals Sterol regulatory element binding protein and dietary lipid regulation of fatty acid synthesis in the mammary epithelium

2010 ◽  
Vol 299 (6) ◽  
pp. E918-E927 ◽  
Author(s):  
Michael C. Rudolph ◽  
Jenifer Monks ◽  
Valerie Burns ◽  
Meridee Phistry ◽  
Russell Marians ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Regulatory Element ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Mrna Levels ◽  
Sterol Regulatory Element

The lactating mammary gland synthesizes large amounts of triglyceride from fatty acids derived from the blood and from de novo lipogenesis. The latter is significantly increased at parturition and decreased when additional dietary fatty acids become available. To begin to understand the molecular regulation of de novo lipogenesis, we tested the hypothesis that the transcription factor sterol regulatory element binding factor (SREBF)-1c is a primary regulator of this system. Expression of Srebf1c mRNA and six of its known target genes increased ≥2.5-fold at parturition. However, Srebf1c-null mice showed only minor deficiencies in lipid synthesis during lactation, possibly due to compensation by Srebf1a expression. To abrogate the function of both isoforms of Srebf1, we bred mice to obtain a mammary epithelial cell-specific deletion of SREBF cleavage-activating protein (SCAP), the SREBF escort protein. These dams showed a significant lactation deficiency, and expression of mRNA for fatty acid synthase ( Fasn), insulin-induced gene 1 ( Insig1), mitochondrial citrate transporter ( Slc25a1), and stearoyl-CoA desaturase 2 ( Scd2) was reduced threefold or more; however, the mRNA levels of acetyl-CoA carboxylase-1α ( Acaca) and ATP citrate lyase ( Acly) were unchanged. Furthermore, a 46% fat diet significantly decreased de novo fatty acid synthesis and reduced the protein levels of ACACA, ACLY, and FASN significantly, with no change in their mRNA levels. These data lead us to conclude that two modes of regulation exist to control fatty acid synthesis in the mammary gland of the lactating mouse: the well-known SREBF1 system and a novel mechanism that acts at the posttranscriptional level in the presence of SCAP deletion and high-fat feeding to alter enzyme protein.

Chloroacetamide Mode of Action, I: Inhibition of Very Long Chain Fatty Acid Synthesis in Scenedesmus acutus

1998 ◽  
Vol 53 (11-12) ◽  
pp. 995-1003 ◽  
Keyword(s):  
Fatty Acids ◽  
Cell Wall ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Acid Synthesis ◽  
Resistant Cell Line ◽  
Long Chain Fatty Acids ◽  
Scenedesmus Acutus ◽  
Long Chain ◽  
Chain Fatty Acids

Abstract Herbicidal chloroacetamides cause a very sensitive inhibition of fatty acid incorporation into an insoluble cell wall fraction of Scenedesmus acutus. The molecular basis was investigated in more detail. After incubation of the algae with [14C]oleic acid and saponification, the remaining pellet was solubilized and fractionated consecutively with chloroform / methanol, phosphate buffer, amylase, pronase, and finally with dioxane/HCl. By acid hydrolysis in dioxane a part of the cell wall residue was solubilized showing inhibition of exogenously applied oleic acid and other labelled precursors such as stearic acid, palmitic acid, and acetate. After extraction of this dioxane-soluble subfraction with hexane, HPLC could separate labelled metabolites less polar than oleic acid. T heir formation was completely inhibited by chloroacetam ides, e.g. 1 μᴍ metazachlor. This effect was also observed with the herbicidally active 5-enantiomer of metolachlor while the inactive R-enantiomer had no influence. These strongly inhibited metabolites could be characterized by radio-HPLC /MS as very long chain fatty acids (VLCFAs) with a carbon chain between 20 and 26. Incubating am etazachlor-resistant cell line of S. acutus (Mz-1) with [14C]oleic acid, V LCFA s could not be detected in the dioxane/ HCl-subfraction. Furthermore, comparing the presence of endogenous fatty acids in wildtype and mutant Mz-1 the VLCFA content of the mutant is very low, while the content of long chain fatty acids (C16 -18) is increased, particularly oleic acid. Obviously, the phytotoxicity of chloroacetam ides in S. acutus is due to inhibition of VLCFA synthesis. The resistance of the mutant to metazachlor has a bearing on the higher amount of long chain fatty acids replacing the missing VLCFAs in essential membranes or cell wall components.

scholarly journals A Review of the Metabolic Origins of Milk Fatty Acids

2013 ◽  
Vol 5 (3) ◽  
pp. 270-274 ◽  
Author(s):  
Anamaria COZMA ◽  
Doina MIERE ◽  
Lorena FILIP ◽  
Sanda ANDREI ◽  
Roxana BANC ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Milk Fat ◽  
De Novo ◽  
Long Chain Fatty Acids ◽  
De Novo Synthesis ◽  
Ruminal Biohydrogenation ◽  
Long Chain ◽  
Chain Fatty Acids

Milk fat and its fatty acid profile are important determinants of the technological, sensorial, and nutritional properties of milk and dairy products. The two major processes contributing to the presence of fatty acids in ruminant milk are the mammary lipogenesis and the lipid metabolism in the rumen. Among fatty acids, 4:0 to 12:0, almost all 14:0 and about a half of 16:0 in milk fat derive from de novo synthesis within the mammary gland. De novo synthesis utilizes as precursors acetate and butyrate produced through carbohydrates ruminal fermentation and involves acetyl-CoA carboxylase and fatty acid synthetase as key enzymes. The rest of 16:0 and all of the long-chain fatty acids derive from mammary uptake of circulating lipoproteins and nonesterified fatty acids that originate from digestive absorption of lipids and body fat mobilization. Further, long-chain fatty acids as well as medium-chain fatty acids entering the mammary gland can be desaturated via Δ-9 desaturase, an enzyme that acts by adding a cis-9-double bond on the fatty acid chain. Moreover, ruminal biohydrogenation of dietary unsaturated fatty acids results in the formation of numerous fatty acids available for incorporation into milk fat. Ruminal biohydrogenation is performed by rumen microbial population as a means of protection against the toxic effects of polyunsaturated fatty acids. Within the rumen microorganisms, bacteria are principally responsible for ruminal biohydrogenation when compared to protozoa and anaerobic fungi.

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