OBSERVATIONS ON A SUBSTANCE IN HUMAN PLASMA WHICH GIVES A SLOW CONTRACTION OF GUINEA‐PIG GUT <i>IN VITRO</i>

Y, Gabr

doi:10.1111/j.1476-5381.1956.tb01034.x

Cited by 21 publications

(14 citation statements)

References 16 publications

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“…The diethenoid linoleic (octadeca-9:12-dienoic) acid has some stimulating effect on the guinea-pig's intestine, as was shown by Gabr (1956), but according to Vogt (1957 b) the effect is only weak and cannot be regularly obtained, thus differing from that due to irin. On the hamster colon linoleic acid was inactive in doses of 70-100 pg.…”

Section: Carboxylic Acidsmentioning

confidence: 93%

“…Purified irin does in fact give a colour test characteristic of the higher fatty acids (see p. 269). However, it is mentioned by Gabr (1956) that the C2-018 saturated fatty acids are pharmacologically inactive, and Vogt (1957 b) has reported that stearic acid is inert on the guinea-pig ileum. In the present investigation two acids of this type were tested on the rat colon: Na acetate (50-200,ug) and neutralized n-caproic acid (100ug).…”

Section: Carboxylic Acidsmentioning

confidence: 99%

“…On the hamster colon linoleic acid was inactive in doses of 70-100 pg. The triethenoid linolenic acid renders the guinea-pig gut insensitive to stimulants (Gabr, 1954).…”

Section: Carboxylic Acidsmentioning

confidence: 99%

“…For instance Gabr (1954) found that the smooth-muscle--contracting activity of octadec-3-enoic acid was considerably reduced after heating with alkali, probably as a result of isomerization. The inactivation of irin by alkali might perhaps be explained by isomerization (or by racemization) to an inactive derivative.…”

Section: Rc-omentioning

confidence: 99%

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Further studies on the preparation, purification and nature of irin

Ambache¹

1959

The Journal of Physiology

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Distilled water extracts of rabbit iris contain an acid which is physiologically active on certain smooth muscles (Ambache, 1957a). Improvements in the purification and assay of this substance are now described and also an investigation of its chemical nature. First, a number of acids of biological origin have been screened for activity. Although representative of a variety of structuretypes, the acids examined are nearly all inactive or can be otherwise distinguished from irin. Direct evidence is then produced that irin is a long-chain unsaturated hydroxy-fatty acid. Further structure-action studies on available hydroxy-acids and lactones have shown that (+ )-ricinoleic acid is a powerful stimulant of the smooth muscle in the hamster colon, whereas oleic acid which lacks the hydroxyl group of ricinoleic but is otherwise identical with it, is relatively inert. These and other findings suggest that an OH group, a double bond, and the spatial relation between them, determine the irin-like activity of fatty acids. METHODSIrin. The source of active material has been the rabbit's iris throughout; although ox irides are larger and would have been more plentiful they contain less than &-O jO the activity found in rabbits' irides. The procedure for making iris extracts described in the previous paper was modified slightly as follows: (i) unless otherwise stated all extracts were made in distilled water (1 ml./ 100mg tissue) neutralized when necessary with 0.02% NaHCO3; (ii) as the pharmacological activity of'extracts is reduced by boiling, the heating was omitted-instead, the centrifuged extracts were left for some days at -15°C, which precipitates out further impurities removable by a second or third centrifugation; (iii) the irides were excised more rapidly, by direct removal through a slit in the cornea without prior enucleation of the eyes. I am indebted to Dr B. C. Whaler for'four extracts of several hundred irides prepared in this way at Porton. For these, the dried irides were ground, unweighed, in 0*4 ml. of distilled water per iris, i.e. assuming an average weight of 40 mg per iris; the dosage of these extracts is expressed in arbitrary units of' _ mg'; (iv) some extracts were prepared from irides excised a few hours after death. Through the courtesy of Dr M. Sterne the severed heads from rabbits killed at the Wellcome Research Laboratories in the morning were sent here, where the eyes were excised and the irides were extracted in the early afternoon. Such extracts were rather less active than those made from fresh irides.

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Section: Carboxylic Acidsmentioning

confidence: 93%

Section: Carboxylic Acidsmentioning

confidence: 99%

“…On the hamster colon linoleic acid was inactive in doses of 70-100 pg. The triethenoid linolenic acid renders the guinea-pig gut insensitive to stimulants (Gabr, 1954).…”

Section: Carboxylic Acidsmentioning

confidence: 99%

Section: Rc-omentioning

confidence: 99%

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Further studies on the preparation, purification and nature of irin

Ambache¹

1959

The Journal of Physiology

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“…"Darmstoff," extracted from the intestine is probably acetalphosphatidic acid; this compound stimulates intestinal smooth muscle, but possesses little depressor activity. 17 G-acid, 18 and hemolytic acid, 19 from human plasma, are straight chain unsaturated monocarboxylic acids without hydroxyl or keto groups and are probably A-3-octadecenoic and cis-A-11-octadecenoic acid (cis-vaccenic acid) respectively. 20 Slow reacting substance A 21 from guinea pig lung produces only slow contraction of isolated nonvascular smooth muscle.…”

Section: Concentration-effect Curves Of the Stimulation Of Iso-mentioning

confidence: 99%

Renomedullary Vasodepressor Substance, Medullin

Lee

Covino

Takman

et al. 1965

Circulation Research

163

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The chemical and physiological properties of renomedullary depressor substances were investigated utilizing the normotensive, vagotomized, pentolinium-treated rat for assay. By a combination of solvent extraction, column chromatography, and thin-layer chromatography, three biologically active acidic lipids were isolated from rabbit renal medulla. The first compound, called medullin, is an acidic lipid with potent vasodepressor and relatively weak nonvascular smooth muscle-stimulating properties. Ultraviolet analysis revealed spectra closely resembling that of prostaglandin E-1 (PGE-1). Infrared analysis showed the presence of carbonyl, methylene, and hydroxyl groups in addition to trans ethylene bonds. Although closely resembling PGE-1, medullin appears to be a more unsaturated carboxylic lipid with less polar (hydroxyl) groups. The hypotensive action of medullin is attributable to a direct effect on peripheral arteriolar beds without cardiac depression, because intra-arterial and intravenous injections of medullin reduced peripheral resistance markedly and increased cardiac output simultaneously. In addition, no effect on cardiac rate or contractility was observed in the isolated rabbit heart preparation. Comparative studies of medullin and PGE-1 indicated that the hypotensive activity of these compounds is similar with respect to potency and mechanism of action. The only biological difference between crystalline PGE-1 and medullin was a fiftyfold greater stimulation of nonvascular smooth muscle by PGE-1 in comparison to medullin. A second biologically active acidic lipid isolated from rabbit medulla was tentatively identified as PGE-1, and was found to possess both vasodepressor and nonvascular smooth muscle-stimulating properties. The third isolate from rabbit medulla possessed potent intestinal stimulating activity but weak to absent vasodepressor effects, properties similar to those of prostaglandin F compounds.

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Chromatographie darmerregender lipoidl�slicher S�uren an SiO2

Vogt

1960

Naunyn - Schmiedebergs Arch

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OBSERVATIONS ON A SUBSTANCE IN HUMAN PLASMA WHICH GIVES A SLOW CONTRACTION OF GUINEA‐PIG GUT IN VITRO

Cited by 21 publications

References 16 publications

Further studies on the preparation, purification and nature of irin

Further studies on the preparation, purification and nature of irin

Renomedullary Vasodepressor Substance, Medullin

Chromatographie darmerregender lipoidl�slicher S�uren an SiO2

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