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PubMed1995

Fatty acid substrate specificities of human prostaglandin-endoperoxide H synthase-1 and -2. Formation of 12-hydroxy-(9Z, 13E/Z, 15Z)- octadecatrienoic acids from alpha-linolenic acid.

Human prostaglandin-endoperoxide H synthase-1 and -2 (hPGHS-1 and hPGHS-2) were expressed by transient transfection of COS-1 cells. Microsomes prepared from the transfected cells were used to measure the rates of oxygenation of several 18- and 20-carbon polyunsaturated fatty acid substrates including eicosapentaenoic, arachidonic, dihomo-gamma-linolenic > alpha-linolenic (delta 9, 12, 15), gamma-linolenic, and linoleic acids. Comparisons of kcat/Km values indicate that the order of efficiency of oxygenation is arachidonate > dihomo-gamma-linolenate > linoleate > alpha-linolenate for both isozymes; while the order of efficiency was the same for hPGHS-1 and hPGHS-2, alpha-linolenate was a particularly poor substrate for hPGHS-1. Gamma-Linolenate and eicosapentaenoate were poor substrates for both isozymes, but in each case, these two fatty acids were better substrates for hPGHS-2 than hPGHS-1. These studies of substrate specificities are consistent with previous studies of the interactions of PGHS isozymes with nonsteroidal anti-inflammatory drugs that have indicated that the cyclooxygenase active site of PGHS-2 is somewhat larger and more accommodating than that of PGHS-1. The major products formed from linoleate and alpha-linolenate were characterized. 13-Hydroxy-(9Z,11E)-octadecadienoic acid was found to be the main product formed from alpha-linoleate by both isozymes. The major products of oxygenation of alpha-linolenate were determined by mass spectrometry to be 12-hydroxy-(9Z,13E/Z,15Z)-octadecatrienoic acids. This result suggests that alpha-linolenate is positioned in the cyclooxygenase active site with a kink in the carbon chain such that hydrogen abstraction occurs from the omega 5-position in contrast to abstraction of the omega 8-hydrogen from other substrates.

Animals↗

PubMed1978

The effect of dihomo-gamma-linolenic acid (20: 3,n-6) on the composition of phospholipid fatty acids in the liver of rats deficient in essential fatty acids.

1. Rats were fed on either a diet deficient in essential fatty acid (EFA) or one supplemented with dihomo-gamma-linolenic acid (20:3,n-6) at levels that represented 0.25, 0.5, 1.0 and 2.0% of the dietary energy. 2. Supplementation of the diet of EFA-deficient animals with 20:3,n-6 reversed most of the fatty acid changes induced in the liver phospholipid fraction. 3 The EFA potency of 20:3,n-6 was found to be similar to that of gamma-linolenic acid (18:3,n-6) which has been shown to be higher than that of linoleic acid (18:2,n-6).

8,11,14-Eicosatrienoic Acid↗

PubMed2004

Lipoic acid and ascorbic acid affect plasma free amino acids selectively in the teleost fish pacu (Piaractus mesopotamicus).

Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied, LA and AA independently affect selected plasma FAA in pacu, and suggest that any use of LA in particular as a dietary supplement should take into account an altered plasma FAA profile.

Amino Acids↗

PubMed2004

Conjugated linoleic acid isomers and trans fatty acids inhibit fatty acid transport in hepatoma 7288CTC and inguinal fat pads in Buffalo rats.

Conjugated linoleic acid (CLA) and some trans fatty acids (FA) decrease tumor growth and alter tumor and host lipid uptake and storage. The goal of this study was to test the hypothesis that the acute inhibitory effects of CLA isomers and trans FAs on FA transport in tumors and white adipose tissue are mediated via an inhibitory G-protein coupled (GPC), FFA receptor (FFAR). Experiments were performed in hepatoma 7288CTC and inguinal fat pads in Buffalo rats during perfusion in situ. CLA isomers and trans FAs (0.03-0.4 mmol/L, in plasma) were added to the arterial blood, and FA uptake or release was measured by arterial minus venous difference. In hepatoma 7288CTC, the CLA isomers, t10,c12-CLA > (+/-)-9-HODE [13-(S)-hydroxyoctadecadienoic acid] > t9,t11-CLA, and the trans FAs, linolelaidic = vaccenic > elaidic, decreased cAMP content and inhibited FA uptake, 13(S)-HODE release, extracellular signal-regulated kinase p44/p42 phosphorylation, and [(3)H]thymidine incorporation. Other CLA isomers, c9,t11-CLA, 13-(S)-HODE, c9,c11-CLA, and c11,t13-CLA, had no effect. In inguinal fat pads, FA transport was inhibited by t10,c12-CLA = linolelaidic acid > trans vaccenic acid, whereas c9,t11-CLA had no effect. In both hepatoma 7288CTC and inguinal fat pad, addition of either pertussis toxin or 8-Br-cAMP to the arterial blood reversed the inhibitions of FA transport. These results support the idea that an inhibitory GPC FFAR reduces cAMP and controls FA transport by CLA isomers and trans FAs. Ligand activity is conferred by the presence of a trans double bond proximal to the carboxyl group.

Adipose Tissue↗

PubMed2003

Plastidial fatty acid signaling modulates salicylic acid- and jasmonic acid-mediated defense pathways in the Arabidopsis ssi2 mutant.

A mutation in the Arabidopsis gene ssi2/fab2, which encodes stearoyl-acyl carrier protein desaturase (S-ACP-DES), results in the reduction of oleic acid (18:1) levels in the mutant plants and also leads to the constitutive activation of NPR1-dependent and -independent defense responses. By contrast, ssi2 plants are compromised in the induction of the jasmonic acid (JA)-responsive gene PDF1.2 and in resistance to the necrotrophic pathogen Botrytis cinerea. Although S-ACP-DES catalyzes the initial desaturation step required for JA biosynthesis, a mutation in ssi2 does not alter the levels of the JA precursor linolenic acid (18:3), the perception of JA or ethylene, or the induced endogenous levels of JA. This finding led us to postulate that the S-ACP-DES-derived fatty acid (FA) 18:1 or its derivative is required for the activation of certain JA-mediated responses and the repression of the salicylic acid (SA) signaling pathway. Here, we report that alteration of the prokaryotic FA signaling pathway in plastids, leading to increased levels of 18:1, is required for the rescue of ssi2-triggered phenotypes. 18:1 levels in ssi2 plants were increased by performing epistatic analyses between ssi2 and several mutants in FA pathways that cause an increase in the levels of 18:1 in specific compartments of the cell. A loss-of-function mutation in the soluble chloroplastic enzyme glycerol-3-phosphate acyltransferase (ACT1) completely reverses SA- and JA-mediated phenotypes in ssi2. In contrast to the act1 mutation, a loss-of-function mutation in the endoplasmic reticulum-localized omega6 oleate desaturase (FAD2) does not alter SA- or JA-related phenotypes of ssi2. However, a mutation in the plastidial membrane-localized omega6 desaturase (FAD6) mediates a partial rescue of ssi2-mediated phenotypes. Although ssi2 fad6 plants are rescued in their morphological phenotypes, including larger size, absence of visible lesions, and straight leaves, these plants continue to exhibit microscopic cell death and express the PR-1 gene constitutively. In addition, these plants are unable to induce the expression of PDF1.2 in response to the exogenous application of JA. Because the act1 mutation rescues all of these phenotypes in ssi2 fad6 act1 triple-mutant plants, act1-mediated reversion may be mediated largely by an increase in the free 18:1 content within the chloroplasts. The reversion of JA responsiveness in ssi2 act1 plants is abolished in the ssi2 act1 coi1 triple-mutant background, suggesting that both JA- and act1-generated signals are required for the expression of the JA-inducible PDF1.2 gene. Our conclusion that FA signaling in plastids plays an essential role in the regulation of SSI2-mediated defense signaling is further substantiated by the fact that overexpression of the N-terminal-deleted SSI2, which lacks the putative plastid-localizing transit peptide, is unable to rescue ssi2-triggered phenotypes, as opposed to overexpression of the full-length protein.

Arabidopsis↗

PubMed1994

The biosynthetic gene cluster for coronamic acid, an ethylcyclopropyl amino acid, contains genes homologous to amino acid-activating enzymes and thioesterases.

Coronamic acid (CMA), an ethylcyclopropyl amino acid derived from isoleucine, functions as an intermediate in the biosynthesis of coronatine, a chlorosis-inducing phytotoxin produced by Pseudomonas syringae pv. glycinea PG4180. The DNA required for CMA biosynthesis (6.9 kb) was sequenced, revealing three distinct open reading frames (ORFs) which share a common orientation for transcription. The deduced amino acid sequence of a 2.7-kb ORF designated cmaA contained six core sequences and two conserved motifs which are present in a variety of amino acid-activating enzymes, including nonribosomal peptide synthetases. Furthermore, CmaA contained a spatial arrangement of histidine, aspartate, and arginine residues which are conserved in the ferrous active site of some nonheme iron(II) enzymes which catalyze oxidative cyclizations. The deduced amino acid sequence of a 1.2-kb ORF designated cmaT was related to thioesterases of both procaryotic and eucaryotic origins. These data suggest that CMA assembly is similar to the thiotemplate mechanism of nonribosomal peptide synthesis. No significant similarities between a 0.9-kb ORF designated cmaU and other database entries were found. The start sites of two transcripts required for CMA biosynthesis were identified in the present study. pRG960sd, a vector containing a promoterless glucuronidase gene, was used to localize and study the promoter regions upstream of the two transcripts. Data obtained in the present study indicate that CMA biosynthesis is regulated at the transcriptional level by temperature.

Amino Acid Sequence↗

PubMed1978

Ranking of excitatory amino acids by the antagonists glutamic acid diethylester and D-alpha-aminoadipic acid.

A separation of the excitatory actions of the amino acids upon thalamic neurones of rats anaesthetized with urethane has been accomplished through the use of two antagonists. It has been possible to rank the excitatory compounds in their order of susceptibility to D-alpha-aminoadipic acid (DalphaAA) and L-glutamic acid diethylester (GDEE). The observation that the ranking orders of the excitants differ for these two antagonists permits an analysis of the types of receptors with which the amino acid excitants react. The results support the proposition that more than one neuronal receptor sensitive to the amino acids exists.

2-Aminoadipic Acid↗

PubMed1984

Effect of 15-hydroxyeicosatetraenoic acid (15-HETE) on anti-immunoglobulin E- and calcium ionophore-induced histamine release from human leukocytes. Comparison with the effects of eicosatetraynoic acid and nordihydroguaiaretic acid.

15-Hydroxyeicosatetraenoic acid (15-HETE) was prepared by soybean lipoxygenase-mediated oxygenation of arachidonic acid to 15-hydroperoxyeicosatetraenoic acid (15-HETE) and subsequent reduction by NaBH4. 15-HETE was identified, purified and proved as biologically active by thin layer chromatography, high pressure liquid chromatography, gas chromatography/mass spectrometry and biological experiments on horse thrombocytes and rabbit peritoneal leukocytes. 15-HETE (0.1-40 microM) was added to peripheral leukocytes of 48 human donors (33 atopics, 15 nonatopics) which were challenged with rabbit anti-human-IgE or calcium ionophore A 23187. Its effect was compared with the effects of nordihydroguaiaretic acid (NDGA) and eicosatetraynoic acid (ETYA). NDGA and ETYA markedly inhibited histamine release (17 microM: 74 +/- 11 and 39 +/- 14,3%, respectively), whereas 15-HETE neither stimulated nor inhibited spontaneous anti-IgE- or calcium ionophore A 23187-induced histamine release.

5,8,11,14-Eicosatetraynoic Acid↗

PubMed2001

Solid-state conformation of a hybrid tripeptide between beta-amino acid; 8-aminocyclooct-4-enecarboxylic acid and 2-aminoisobutyric acid.

An eight-membered cyclic beta-amino acid, 8-aminocyclooct-4-enecarboxylic acid, was designed as a conformationally restricted non-proteinogenic amino acid. A hybrid tripeptide containing this eight-membered cyclic beta-amino acid and 2-aminoisobutyric acids was synthesized by conventional solution methods. The conformation of the tripeptide was studied using X-ray analysis and was shown to form an eleven-membered hydrogen-bonded turn (3(11)-helical structure) in the solid state.

Amino Acids↗

PubMed1977

[A simple method for the simultaneous analysis of urinary homovanillic acid, vanilmandelic acid and 3, 4-dihydroxy mandeli acid by mass fragmentography (author's transl)].

Gas chromatography-mass spectrometry makes possible the simultaneous measurement of homovanillic acid (HVA), vanilmandelic acid (VMA) and 3, 4-dihydroxy mandelic acid (DOMA) in 2ml urine samples. The equipment used was the Shimadzu LKB 9000 GC-MS (MID-PM). The TMSi derivatives of the compounds were analysed by the GC-MS system equipped with a 3ft. X 3mm column packed with 1.5% OV-1 and the temperature was programed from 130 degrees to 260 degrees C at 10 degrees C/min increments. The mass spectrum showed molecular ions at m/e 326, 414, and 472 which correspond to the TMSi derivatives of HVA, VMA AND DOMA respectively. The peaks at m/e 326 (HVA), 297 (VMA) and 355 (DOMA) were applied to avail themselves of simultaneous multiple ion analyses by GC-MS. As little as 1pg of the compounds injected into the column could be measured reproducibly. The sensitivity is of the order of pg or ng, and the linearity of the response is maintained up to at least 200ng. The procedure was simpler and less time consuming than previous methods. It consists of extraction of the free acid into ether followed by complete silylation of the phenolic, alcoholic and carboxylic acid group with bis (trimethylsilyl) acetamide. Recoveried of HVA, VMA, DOMA added to urine were 93.8%, 71.2% and 23.6% respectively. The specificity of this method surpasses and cannot be compared to any other existing quantitative methods.

Gas Chromatography-Mass Spectrometry↗

PubMed1990

[Age estimation by amino acid racemization in teeth. A comparison of data for aspartic acid, glutamic acid and alanine].

On the age estimation by the amino acid racemization analysis of dentin, besides the utilization of aspartic acid (Asp) as described in earlier reports, we further studied relationships between the D/L ratios based on glutamic acid (Glu) as well as alanine (Ala) and actual ages. The study was followed up by comparing racemization velocities of the three amino acids under some heating experiments. At four steps (6, 24, 48 and 72 hours) of hydrolysis, the coefficient values of D/L ratio of each amino acid and actual age were calculated as 0.986 to 0.994 for Asp, 0.522 to 0.806 for Glu, and 0.577 to 0.737 for Ala. The data indicate that Asp gives an extremely good result. Glu and Ala do provide reliable D/L ratios, however they are not in proportion to actual ages. Consequently, Glu and Ala seem to be much less suitable for utilization in age estimation. Reaction rate constants (k.yr-1) of racemization of Asp, Glu and Ala in antemortem teeth were 5.3825 x 10(-4), 5.1000 x 10(-5) and 2.3875 x 10(-5), respectively. Those in teeth left drying at 15 degrees C were 2.4850 x 10(-8), 1.9119 x 10(-9), and 1.11450 x 10(-9), respectively. Assuming that the reaction velocity of Asp be 1 in both living and dry states, that of Glu were calculated as 0.09 and 0.08, that of Ala, 0.04 and 0.05, indicating very similar rates. The result confirmed that both Glu and Ala gave considerably slow racemization velocities as compared with Asp.

Age Determination by Teeth↗

PubMedDate not supplied

Release of [3H]- and endogenous GABA from slices of the rat medulla oblongata: modification by 3-mercaptopropionic acid, nipecotic acid and diaminobutyric acid.

Slices of the rat medulla oblongata were superfused and electrically stimulated. The amount of [3H]- and endogenous GABA was determined. There was a stimulus-evoked release of [3H]- and endogenous GABA, which was Ca2+-dependent and tetrodotoxin-sensitive. 3-Mercaptopropionic acid (3-MP) reduced the release of endogenous GABA, whereas the release of [3H]-GABA was not affected by this agent. Nipecotic acid enhanced the spontaneous and stimulus-evoked release of both [3H]- and endogenous GABA. 3-MP, nipecotic acid and diaminobutyric acid modified the stimulus-evoked release of endogenous GABA from slices containing the rostral ventrolateral medulla, the caudal ventrolateral medulla or the nucleus tractus solitarii, regions responsible for blood pressure regulation. These results suggest that 3-MP inhibits the stimulus-evoked release of GABA without affecting its release process, whereas nipecotic acid enhances the release via its uptake inhibition action.

3-Mercaptopropionic Acid↗

PubMed1977

[Determination of the urinary metabolites hydroxyindole-acetic acid, vanillyl mandelic acid and homovanillic acid by means of lipophilic gel chromatography and gas chromatography (author's transl)].

A specific and practicable method is described for the quantitative determination of urinary phenol- and indole-carboxylic acids. High specificity is achieved by a preliminary separation of the free acids (extracted from the urine sample) with the aid of organophilic gel chromatography on Sephadex LH 20, followed by gas chromatographic analysis of the silyl derivatives of the acids. The organophilic gel chromatography of the free acids shows a high recovery rate in the micro- and submicrogram range. The difficulties encountered in other techniques in the derivatisation and gas chromatographic separation of the individual components are avoided by using the preliminary separation, and by using N-methyl-N-trimethylsilyl-trifluoroacetamide for the derivatisation. Use of this preparation technique with a direct read-out gas chromatograph with automatic sample introduction, gives high accuracy and precision, and a facility for the determination of a wide range of aromatic acids in urine.

Chromatography, Gas↗

PubMed1994

Evidence for a novel keratinocyte fatty acid uptake mechanism with preference for linoleic acid: comparison of oleic and linoleic acid uptake by cultured human keratinocytes, fibroblasts and a human hepatoma cell line.

Keratinocytes require the essential fatty acid (FA), linoleic acid (LA), for the synthesis of stratum corneum membrane lipids. A plasma membrane-FA binding protein (PM-FABP), is postulated to mediate cellular FA-uptake in hepatocytes and several other tissues, but the mechanism whereby exogenous FA are taken up by keratinocytes has not been investigated. This study examines the uptake of LA and oleic acid (non-essential) in cultured human keratinocytes, in comparison to dermal fibroblasts and the human hepatoma cell line, HepG2. As previously reported for hepatocytes, FA-uptake in keratinocytes was curvilinear, with an initial (30 s) rapid cellular influx. The initial uptake component was temperature dependent, exhibited saturable kinetics and was significantly inhibited by pretreatment with trypsin. In contrast, fibroblast FA-uptake lacked an initial rapid uptake component, was relatively temperature insensitive, and was not inhibited by trypsin. Keratinocytes differed from both hepatocytes and fibroblasts by more rapid uptake of LA in comparison to oleic acid during the initial influx phase. Moreover, FA-uptake in keratinocytes was not inhibited by preincubation with a anti-rat liver PM-FABP antibody. These data provide evidence for a PM-FA transporter in keratinocytes that is distinct from the hepatic PM-FABP. The apparent preference of the putative keratinocyte FA transporter for LA may function to ensure epidermal capture of sufficient LA for barrier lipid synthesis.

Adult↗

PubMed2007

Structures of the high-temperature solid phases of the odd-numbered fatty acids from tridecanoic acid to tricosanoic acid.

Crystal structures of the high-temperature phases of odd-numbered fatty acids (C(n)H(2n-1)OOH) from tridecanoic acid (C(13)H(25)OOH) to tricosanoic acid (C(23)H(45)OOH) are presented in this article. They have been determined from high-quality X-ray powder-diffraction patterns. Two types of high-temperature phases are adopted: one monoclinic A2/a with Z=8 for the fatty acids with n=13 and n=15, denoted as C'', and one monoclinic P2(1)/a with Z=4 for the longer-chain fatty acids, denoted as C'. It appears that the packing arrangement of the alkyl chains and of the carboxyl groups is similar in all of the structures. However, the arrangement at the methyl-group interface differs between the C' and C'' forms. A survey of the intermolecular interactions involved in these polymorphs coupled with a study of the effects of temperature on the structures have led us to a better understanding of the arrangement of the molecules within the high-temperature solid phases of odd-numbered fatty acids.

Journal Article↗

PubMed1977

[The effect of nutritional factors on the ruminal mucosa. 3. Condition of the mucosa after infusion of propionic acid, acetic acid and butyric acid].

Three non-lactating cows (Deutsches Schwarzbuntes Rind) with large ruminal fistulas were fed coarsely structured food. Within a trial period of 21 weeks infusion periods lasting 3 weeks alternated with equally long control periods (K). During the 3 infusion periods, 8.4 mMol of propionic acid (P), 14.8 mMol of acetic acid (E) and 4,5 mMol of butyric acid (B) per kg liveweight per day were administered through the fistula, the total quantity being 19 litres of solution. In the periods K1...4 the ruminal fluid contained an average of 68 Mol% E, 19 Mol% P, 13 Mol% B (maximum of 10.25 mMol free fatty acids (FFS) per 100 ml, minimum pH 6.4). In the course of the 10 hrs of infusion the Mol percentages of the particular acids infused increased to 27% P (maximum of 11.14 mMol FFS per 100 ml, minimum pH 6.4) or 79% E (maximum of 12,99 mMol FFS per 100 ml, minimum pH 6.0 (5.5)) or 25% B (maximum of 10.34 mMol FFS per 100 ml, minimum pH 6.0 (5.5)). Infusions of E and B had the most pronounced effect on the ruminal mucosa compared with the K periods. All fatty acids increased the process of keratinization and decreased the size of cell nuclei in the stratum basale. As specific effect, P infusions produced a thickening of the lamina propria; B infusions caused a thickening of the stratum germinativum (proliferative effect) while e infusions led to a drastically reduced thickness of villi (antiproliferative effect) due to reductions in the stratum germinativum and the lamina propria. According to the morphological situation high specific mucosal function is suggested during the B-period. The mucosa appeared quite normal during all periods investigated, with the exception of the E period, where hyperkeratosis, atrophy and necrosis were observed in 34% of the sample. Changes in the state of the mucosa appeared as early as 1 week after the beginning of the respective trial periods. Keratin consolidation was the primary cause for chemically induced keratosis. The development of hyperkeratosis seemed to be favoured if low pH values occurred in the rumen in combination with small amounts of metabolites inducing proliferation, both representing synergistic factors.

Acetates↗

PubMed1991

Effect of Exogenous Indole-3-Acetic Acid and Indole-3-Butyric Acid on Internal Levels of the Respective Auxins and Their Conjugation with Aspartic Acid during Adventitious Root Formation in Pea Cuttings.

The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on the internal levels of these auxins was studied during the first 4 days of adventitious root formation in cuttings of Pisum sativum L. The quantitations were done by high performance liquid chromatography with spectrofluorometric detection. IBA, identified by combined gas chromatography-mass spectrometry (GC-MS), was found to naturally occur in this plant material. The root inducing ability of exogenous IBA was superior to that of IAA. The IAA level in the tissue increased considerably on the first day after application of IAA, but rapidly decreased again, returning to a level twice the control by day 3. The predominant metabolic route was conjugation with aspartic acid, as reflected by the increase in the level of indole-3-acetylaspartic acid. The IBA treatment resulted in increases in the levels of IBA, IAA, and indole-3-acetylaspartic acid. The IAA content rapidly returned to control levels, whereas the IBA level remained high throughout the experimental period. High amounts of indole-3-butyrylaspartic acid were found in the tissue after feeding with IBA. The identity of the conjugate was confirmed by (1)H-nuclear magnetic resonance and GC-MS. IBA was much more stable in solution than IAA. No IAA was detected after 48 hours, whereas 70% IBA was still recovered after this time. The relatively higher root inducing ability of IBA is ascribed to the fact that its level remained elevated longer than that of IAA, even though IBA was metabolized in the tissue. Adventitious root formation is discussed on the basis of these findings.

Journal Article↗

PubMedDate not supplied

Correlations between conceptal concentrations of all-trans-retinoic acid and dysmorphogenesis after microinjections of all-trans-retinoic acid, 13-cis-retinoic acid, all-trans-retinoyl-beta-glucuronide, or retinol in cultured whole rat embryos.

Retinol (4,000 ng/ml), all-trans-retinoyl-beta-glucuronide (4,000 ng/ml), and 13-cis-retinoic acid (1,500 ng/ml) each produced dysmorphogenic effects qualitatively similar to those elicited by 250 ng/ml of all-trans-retinoic acid after microinjections of the respective individual retinoids into the amniotic cavities of cultured whole rat embryos. Subsequent HPLC analyses of the cultured whole conceptuses, embryos proper, yolk sacs, and culture media (24 hr after microinjections) indicated that conceptal biotransformation of each of the retinoids had occurred during the culture period. All-trans-retinoic acid was present in the embryos proper at quantitatively similar concentrations (20-100 nM) after microinjections of the selected quantities of each of the microinjected retinoids: retinol, all-trans-retinoyl-beta-glucuronide, 13-cis-retinoic acid, or all-trans-retinoic acid. The results suggested that all-trans-retinoic acid acted as an ultimate dysmorphogen for the retinoids tested with respect to the anomalies monitored in the embryo culture system.

Abnormalities, Drug-Induced↗