Rectal Secretion Research Articles

ChemInform Abstract: An (S)‐(+)‐Lactic Acid Route to (2S,6R,8S)‐2,8‐Dimethyl‐1,7‐dioxaspiro(5.5)undecane (‐)‐(IX) and (2S,6R,8S)‐2‐Ethyl‐8‐methyl‐1,7‐dioxaspiro(5.5)undecane (‐)‐(VII) and Demonstration of Their Presence in the Rectal Glandular Secretion of Bactrocera nigrotibialis (Perkins).

ChemInformVolume 21, Issue 52 Natural Products ChemInform Abstract: An (S)-(+)-Lactic Acid Route to (2S,6R,8S)-2,8-Dimethyl-1,7-dioxaspiro(5.5)undecane (-)-(IX) and (2S,6R,8S)-2-Ethyl-8-methyl-1,7-dioxaspiro(5.5)undecane (-)-(VII) and Demonstration of Their Presence in the Rectal Glandular Secretion of Bactrocera nigrotibialis (Perkins). M. V. PERKINS, M. V. PERKINS Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this authorW. KITCHING, W. KITCHING Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this authorW. A. + KOENIG, W. A. + KOENIG Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this authorR. A. I. DREW, R. A. I. DREW Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this author M. V. PERKINS, M. V. PERKINS Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this authorW. KITCHING, W. KITCHING Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this authorW. A. + KOENIG, W. A. + KOENIG Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this authorR. A. I. DREW, R. A. I. DREW Dep. Chem., Univ. Queensl., St. Lucia, Queensl., Aust. 4072Search for more papers by this author First published: December 25, 1990 https://doi.org/10.1002/chin.199052350Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume21, Issue52December 25, 1990 RelatedInformation

Rectal electrogenic secretion‐‐is it a putative indicator of intestinal secretory status induced by nutritional deprivation in the rat?

Intestinal secretion is enhanced by starvation in rats. The rectum from fed and 3-day-starved rats generates a basal electrogenic ion transfer (short-circuit current) in vitro which is mainly electrogenic Na+ absorption (amiloride-sensitive, 66-71%) with a small component of electrogenic chloride secretion (furosemide-sensitive, 14-22%). Bethanechol, a muscarinic agonist, caused an increase in the short-circuit current (mainly furosemide-sensitive chloride secretion) and potential difference in rectums from both fed and starved rats but the respective values for the starved animals were 100% and 64% greater. In starvation, the rat rectum is an indicator of intestinal secretory status. The result warrants investigation of human rectal electrogenic secretion in nutritional deprivation.

An (S)-(+)-lactic acid route to (2S,6R,8S)-2,8 dimethyl-1,7-dioxaspiro[5,5]undecane and (2S,6R,8S)-2-ethyl-8-methyl-1,7-dioxaspiro[5,5]undecane and demonstration of their presence in the rectal glandular secretion of Bactrocera nigrotibialis(Perkins)

The chiral iodide resulting from reduction and iodination of the tetrahydropyran-2-yl ether of ethyl (S)-(+)-lactate has been engaged in a free-radical addition to acrylonitrile. The resulting protected hydroxy nitrite, on reaction with pent-4-enylmagnesium bromide afforded (S)-2-tetrahydropyran-2-yloxyundec-10-en-6-one. Oxymercuriation of this hydroxy enone, under reversible conditions, employing aqueous acid–tetrahydrofuran, effected simultaneous deprotection and cyclisation, and in situ biphasic demercuriation with sodium borohydride provided essentially stereochemically pure (2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane [i.e.the (E,E)-diastereoisomer only]. Epoxidation of the protected hydroxy enone, followed by dimethylcuprate ring-opening and cyclisation, provided a mixture of the (E,E)and the two possible (E,Z)-diastereoisomers of 2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecane with the former being the (2S,6R,8S) stereoisomer. Separation of the (E,E)from the two (E,Z)isomers was achieved by preparative gas chromatography. GC analysis of these samples and of the rectal glandular secretion of male Bactrocera nigrotibialis, using a cyclodextrin-based phase, demonstrated that the (2S,6R,8S)-stereoisomers of the 2,8-dimethyl- and 2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecanes were the natural products, with no detectable level of the antipodes.

Chemistry of fruit flies: composition of the male rectal gland secretions of some species of South-East Asian Dacinae. Re-examination of Dacus cucurbitae(melon fly)

The major components of the rectal glandular secretions of male Dacus (Bactrocera) umbrosus(jack fruit fly), D. (Bactrocera) nigrotibialis, D. (Bactrocera) albistrigatus, D. (Zeugodacus) tau and D. (Zeugodacus) sp. (taxonomically similar to D. tau) have been identified. Alcohols, spiroacetals, and amides are the dominant components. The major component in the rectal gland secretion of Dacus (Zeugodacus) cucurbitae(melon fly) is shown to be ethyl 4-hydroxybenzoate and not 2-ethoxybenzoic acid.

Chemistry of fruit flies. Composition of the rectal gland secretion of (male) Dacus cucumis (cucumber fly) and Dacus halfordiae. Characterization of (Z,Z)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane

Combined gas chromatography-mass spectrometry and synthesis have established that the major components of the rectal gland secretion of adult male cucumber flies (Dacus cucumis) are the E,E, E,Z, and Z,Z diastereomers of 2,8-dimethyl-l,7-dioxaspiro[5.5]undecane, which have been synthesized utilizing organomercury chemistry from l,10-undecadien-6-one. The thermodynamically least stable Z,Z diastereomer has been characterized for the first time, byH andC NMR measurements and mass spectrometry. Minor amounts of 3-hydroxy-2,8-dimethyl-l,7-dioxaspiro[5.5]undecane and various derivatives of the l,6-dioxaspiro[4.5]decane and 1,7-dioxaspiro[5.6]dodecane systems are also present. 1,3-Nonanediol occurs in significant amounts, and both enantiomers have been acquired by Sharpless asymmetric epoxidation of (E)-2-nonen-l-ol followed by Red-Al (Aldrich) reduction of the chiral epoxy alcohols. Chiral gas chromatographic analysis of the diols (as their cyclic carbonates) has demonstrated that the natural material is the R-(-) enantiomer. Natural (E,Z)-2,8-dimethyl-l,7-dioxaspiro-[5.5]undecane is shown to be racemic, whereas the more abundant E,E diastereomer is enantiomerically highly pure, possessing the 2S,6R,8S configuration. The major volatile component of the rectal gland secretion of male Dacus halfordiae (Tryon) is also (E,E)-2,8-dimethyl-l,7-dioxaspiro[5.5]undecane, with no detectable levels of the E,Z or Z,Z isomers. Other spiroacetals present were 2-ethyl-7-methyl-l,6-dioxaspiro[4.5)decane and the unusual even carbon-numbered (E,E)-2-ethyl-8-methyl-l,7-dioxaspiro[5.5]undecane. 6-Oxo-l-nonanol, diethyl succinate, and 2-methyl-6-pentyl-3,4-dihydro-2H-pyran were also identified.

Rectal acid secretion in the desert locust, Schistocerca gregaria

The role played by the rectum in haemolymph pH regulation and the epithelial transport mechanisms involved were investigated in the desert locust ( Schistocerca gregaria) both in vivo and in vitro. Injection-retrieval experiments performed with an in situ ligated rectal preparation demonstrate that the rectal epithelium is capable of generating and maintaining the low pH values observed in the rectum of the intact animal. In vitro experiments in which isolated recta were mounted as flat-sheets in Ussing chambers suggest that the acidification is due to an active H + secretory mechanism rather than selective secretion or reabsorption of either phosphate or bicarbonate. Microelectrode measurements of intracellular pH demonstrate that acid secretion occurs against electrochemical gradients of at least 79 mV at the apical membrane. The level of rectal acidification observed in vivo directly reflected the acid/base status of the animal when locusts were made acidotic by injection with 0.1 N hydrochloric acid. However, contraluminal pH had no effect on rectal acid secretion ( J H) in the in vitro preparation. This suggests that the rectum does have a pH regulatory role, but that it is modulated by some factor(s) other than haemolymph pH per se.

Atrial natriuretic peptide stimulates salt secretion by shark rectal gland by releasing VIP.

Salt secretion by the isolated perfused rectal gland of the spiny dogfish shark, Squalus acanthias, is stimulated by synthetic rat atrial natriuretic peptide (ANP II) as well as extracts of shark heart, but not by 8-bromo-cyclic guanosine 5'-monophosphate. Cardiac peptides have no effect on isolated rectal gland cells or perfused tubules, suggesting that stimulation requires an intact gland. The stimulation of secretion by ANP II is eliminated by maneuvers that block neurotransmitter release. These include: perfusion with procaine (10(-2) M), perfusion with high Mg2+ (9.5 mM) and low Ca2+ (0.5 mM) concentrations, and addition to the perfusate of the calcium channel blockers nifedipine (10(-6)M), diltiazem (5 X 10(-5)M), or verapamil (10(-4)M). Cardiac peptides stimulate the release of vasoactive intestinal peptide (VIP), known to be present in rectal gland nerves, into the venous effluent or perfused glands in parallel with their stimulation of salt secretion, but the release of VIP induced by ANP II is prevented by perfusion with procaine. Cardiac peptides thus appear to regulate rectal gland secretion by releasing VIP from neural stores within the gland. It is possible that other physiological effects of these hormones might be explained by an action to enhance local release of neurotransmitters.

Enhanced rectal potassium secretion in chronic renal insufficiency: evidence for large intestinal potassium adaptation in man.

The role of the large intestine in K+ excretion in chronic renal insufficiency was studied with a rectal dialysis technique in 14 normal subjects and eight normokalaemic, normotensive patients with chronic renal insufficiency. At initial intraluminal K+ concentrations of 10, 20, 30 and 45 mmol/l, net K+ secretion in patients with renal insufficiency was significantly greater than in normal subjects by approximately 1.8 mumol h-1 cm-2. The increase in net K+ secretion was more marked in those patients with creatinine clearances of less than 10 ml/min. In contrast, there were no significant differences in net Na+ and water transport, transmucosal potential difference and plasma aldosterone concentrations between the two groups. With an initial intraluminal K+ concentration of 30 mmol/l, the addition of amiloride (final concentration 1 mmol/l) to the rectal lumen decreased net Na+ absorption and transmucosal potential difference in normal subjects by 69% (P less than 0.005) and 31% (P less than 0.005) respectively, and in patients with renal insufficiency by 75% (P less than 0.05) and 36% (P less than 0.05) respectively, but there was no change in net K+ secretion in either group. These results indicate that the K+ secretory capacity of the rectal mucosa increases in chronic renal insufficiency, and the large intestine may therefore contribute to the maintenance of K+ homoeostasis as renal K+ excretion declines. Increased rectal K+ secretion in renal insufficiency occurs independently of changes in plasma K+ and aldosterone concentrations, net Na+ absorption and transmucosal potential difference, and may reflect stimulation of an active K+ secretory process.

Control of rectal gland secretion in the dogfish (Squalus acanthias): steps in the sequence of activation.

We measured the venous and arterial pressure, as well as the rate of secretion and content of cyclic AMP and high energy phosphate compounds, of the rectal gland of the anaesthetized dogfish, Squalus acanthias (L.). Intravenous infusion of isotonic solutions produced a very large increase in the rate of secretion by the rectal gland. The increase in secretion was preceded by an increase in venous blood pressure, but arterial blood pressure was not modified. Injections of small doses of veratridine stimulated gland secretion when given in the vicinity of the heart but not when given in the dorsal aorta. During volume expansion the creatine phosphate and ATP content of the gland were markedly reduced, while ADP and AMP as well as cyclic AMP content were increased. We conclude that: volume expansion leads to the release of a message that activates adenyl cyclase in the gland; the increased venous pressure may be the initial signal in the sequence that leads to the release of the activating messenger; there is a receptor mechanism in the atrial and cardiac region that triggers the sequence that activates glandular secretion; the reduction in the content of high energy phosphate compounds during volume expansion is caused by an increase in energy expenditure, probably due to gland secretion.

Atriopeptin stimulation of rectal gland function in Squalus acanthias.

The rectal gland of the shark plays a significant role in the homeostasis of extracellular volume. Regulation of rectal gland function is under hormonal control, but the precise identity of the humoral mediator is unknown. Atriopeptin stimulates rectal gland chloride secretion in vivo. This stimulation of epithelial transport is accompanied by systemic and local hemodynamic effects. Atriopeptin also stimulates chloride secretion by the in vitro perfused rectal gland, an effect that is not accompanied by hemodynamic changes. Extracts of shark heart, but not muscle, brain, kidney, or intestine, contain a heat-stable trypsin-sensitive substance capable of in vitro stimulation of rectal gland chloride secretion. Electron micrographic analysis reveals multiple neurosecretory-like granules in atrial cardiocytes that are only rarely seen in ventricular cardiocytes. By using the in vitro perfused gland as a biologic assay, serum obtained after extracellular volume expansion reveals the presence of a rectal gland stimulatory factor that is not present in serum before expansion. These results are consistent with the hypothesis that atriopeptin is present in shark cardiocytes and is released during volume expansion. The atriopeptin stimulates rectal gland chloride secretion, providing a negative feedback mechanism for the regulation of extracellular volume.

Primary role of volume expansion in stimulation of rectal gland function.

Chloride secretion by the in vivo rectal gland of the shark is stimulated by the intravascular infusion of salt solutions of varying osmolar and sodium concentration. In a cross-perfused and denervated rectal gland, the infusion of a small amount of a hypertonic salt solution raises plasma osmolality but does not increase plasma volume in the donor fish. Under these conditions, rectal gland chloride secretion is not stimulated. A subsequent infusion of isotonic shark Ringer solution increases plasma volume 50%, decreases plasma osmolality, and produces a fourfold increase in chloride secretion and a threefold decrease in vascular resistance within the gland. Both the vasodilatory and secretory responses also follow the infusion of a hypotonic shark Ringer solution. The data further support the hypothesis that the rectal gland of the shark is involved in the regulation of intravascular volume rather than in osmoregulation.

Increased Rectal Potassium Secretion in Patients with Chronic Renal Failure (CRF)

Increased Rectal Potassium Secretion in Patients with Chronic Renal Failure (CRF)

An endogenous peptide stimulates secretory activity in the elasmobranch rectal gland.

Extraction and partial purification of peptide material from the intestine of the elasmobranch Scyliorhinus canicula yielded a fraction that shows potent stimulatory activity in the rectal gland. The extracted material appears to contain an endogenous peptide (or peptides) that represents the natural hormone responsible for the control of rectal gland secretion in vivo.

Effects of acidosis and carbonic anhydrase inhibition in the elasmobranch rectal gland.

We studied the effects of acidosis and carbonic anhydrase inhibition on rectal gland fluid secretion. In the anesthetized dogfish shark, Squalus acanthias, volume expanded by a constant infusion of Ringer solution, fluid formation was halved by severe systemic metabolic and respiratory acidosis (pH approximately 7.10) and carbonic anhydrase inhibition. Mild respiratory acidosis (pH approximately 7.6) equivalent to the measured systemic pH during carbonic anhydrase inhibition was without effect. Inhibition of rectal gland enzyme produced severe glandular acidosis, which is indicated by an increase in gland fluid PCO2 (from 7 to 26 mmHg) and HCO3- (from 1.2 to 2.4 mM) and a decrease in pH (from 6.7 to 6.4). Gland tissue total CO2 dropped from 18 to 11 mmol/kg. These changes occurred despite nearly 50% reduction in fluid formation, O2 consumption, and CO2 output. We propose that carbonic anhydrase facilitates CO2 transfer from sites of metabolism to capillary blood by its conversion to HCO3-. This maintains a tolerable intracellular acid-base milieu during stimulated fluid secretion.

In vivo effect of volume expansion on rectal gland function. II. Hemodynamic changes.

Intravascular volume expansion causes a 300% increase in the rate of fluid secretion from, and blood flow to, the in vivo rectal gland of the spiny dogfish Squalus acanthias. Similar increases are also observed in explanted rectal glands perfused through a catheter from the dorsal aorta of a volume-expanded dogfish. Stimulation of rectal gland secretion by volume expansion is not associated with a change in the ratio of chloride secreted to oxygen consumed by the rectal gland and the oxygen extraction ratio, suggesting that an increase in blood flow is necessary to support the increased rate of chloride secretion. Perfusion of the explanted gland with bumetanide (10(-4) M) completely inhibits the secretory response to volume expansion but does not prevent the increase in blood flow. Bumetanide also inhibits dibutyryl adenosine 3',5'-cyclic monophosphate- and theophylline-induced increases in chloride secretion but does not inhibit the hyperemic response. Somatostatin inhibits the secretory response of the explanted gland to volume expansion but does not prevent the increase in blood flow. Although an increase in blood flow is necessary to support the increased energy requirement of enhanced transport, the secretory response and the increase in blood flow appear to be independently regulated and mediated, at least in part, by humoral factors.

Active HCO3- Secretion in the Rectal Salt Gland of A Mosquito Larva Inhabiting NaHCO3–CO3 Lakes

ABSTRACT Aedes dorsalis larvae are one of the few organisms capable of inhabiting hypersaline NaHCO3-CO3 lakes. Under laboratory conditions larvae can survive and develop normally in saline media with pH values of 10·5, HCO3− concentrations of 250 mm, or CO32− concentrations of 100 mm. Despite ingestion of alkaline media at a rate equal to 130% of larval body wt/day, these insects regulated haemolymph pH (7·55–7·70) and HCO3− concentration (8·0–18·5 mm) within narrow limits. Analysis of fluid obtained by micropuncture or microcannulation indicated that rectal secretion is an important mechanism of pH and HCO3− regulation. The lumen-to-haemocoel HCO3− and CO32− gradients generated by isolated, microcannulated recta were 21 :1 and 241 :1, respectively. Transepithelial potential in cannulated recta was – 14·2 to –23·3 mV (lumen negative), demonstrating that net HCO3− secretion occurs against a large electrochemical gradient.

Chemical components of the rectal gland secretions of maleDacus cucurbitae, the melon fly

The volatile constituents of the rectal gland secretion of maleDacus cucurbitae have been shown to contain 2-methoxy-N-3-methylbutyl acetamide together with 2 other amides, 3 pyrazine derivatives and 2-ethoxybenzoic acid. Excised male rectal glands have been demonstrated to elicit strong responses from female melon flies.

Indirect evidence for enhancement of Na-K-ATPase activity with stimulation of rectal gland secretion

The relation between active chloride secretion and Na-K-ATPase activity was studied in the isolated perfused rectal gland of Squalus acanthias stimulated by cAMP and theophylline. Ouabain inhibited both secretion and oxygen uptake in stimulated glands. Stimulation of chloride secretion by cAMP and theophylline resulted in a six- to sevenfold rise in ouabain-inhibitable oxygen consumption. Intracellular sodium concentration decreased while intracellular potassium rose. These findings suggest activation of Na-K-ATPase. On the other hand, the activity of Na-K-ATPase in whole homogenates of rectal gland tissue was not increased after cAMP stimulation of the perfused gland, nor was ouabain binding increased. Calculated intracellular chloride concentration fell after secretion was stimulated in a way consistent with an action of cAMP to increase luminal permeability to chloride.

427 RECTAL TISSUE IMMUNOGLOBULIN PATTERNS IN CHILDREN WITH INFECTIOUS COLITIS

We have employed a single phase antibody radioimmunoassay to determine rectal tissue and secretion immunoglobulin (Ig) levels in children with documented infectious colitis. All children had positive stool culture and/or rectal swab for pathogen, abnormal proctosigmoidoscopy and pathologic diagnosis of acute colitis. Tissue was placed in rectal organ culture for 24 hours and explants were homogenized (H) and assayed for IgA, IgG and IgM. Secretions (S) were collected over center well of organ culture plate and assayed for Ig's. Results were expressed as μg Ig per mg tissue protein. Results were compared with a control population of children with Functional Abdominal Pain who had normal proctosigmoidoscopy and pathogen-negative stool cultures. There appears to be a marked symmetrical increase in rectal tissue Ig's whether comparing total Ig (p<0.005) or individual homogenates (p<0.001) or secretions (p<0.01). The presence of increased amounts of Iga, IgM & IgG in infectious colitis should influence further investigations into other inflammations of the colon (i.e., ulcerative colitis, cow's milk protein-induced colitis. etc.).

Regulation of rectal secretion in saline-water mosquito larvae living in waters of diverse ionic composition.

1. Larvae of the saline-water mosquito Aedes campestris were adapted to three waters, all having an osmotic concentration of 700 mOsm, but differing in ionic rations. The (Na+Mg) SO4 medium was much moretoxic than the NAHCO3 or the NaCl media. 2. Ionic and osmotic concentrations of haemolymph and rectal secretion were measured in larvae adapted to all three media. The ratio of ionic concentrations in the rectal secretion reflected those in the external medium to which the larvae had been adapted, with the exception of SO42-, which was possibly replaced by HCO3-in the secretion. These differences in rectal fluid composition persisted even though all ligated recta were bathed in the same artificial haemolymph. 3. The Malpighian tubules were found to be the major site of SO42- excretion. In media containing high levels of NA+, Mg2+, K+, Cl- and HCO3-, the rectum secreted a hyperosmotic fluid containing these ions at concentrations several times greater than those found in the haemolymph. 4. These data provide the basis for speculation on the functioning of anal papillae in waters of diverse chemical composition.