Liver microsomal Δ6 and Δ5 linoleic acid desaturation in female BB rats

Summary Rat liver microsomal 6 and 5 desaturation are defective in experimental diabetes, but this defect is correctable with insulin treatment. Rat liver fatty acid composition and 6 and 5 desaturation were studied in the spontaneously diabetic adult female Bio-Breeding (BB) rat. Control Wistar rats and BB rats (4 weeks of diabetes), that received insulin (1 IU·100 g body weight^–1·day^–1), were killed 20 h after the last insulin injection. 6 and 5 desaturase activities were estimated from the incubation of liver microsomes with (1-¹⁴C) 18:2, n–6 or (2-¹⁴C) 20:3, n–6, respectively, and the fatty acid composition of the liver and microsomal liver lipids were investigated. Under experimental conditions 6 and 5 desaturase activities were unchanged in the BB rats when compared to the control rats. Impairment of the liver fatty acid composition of diabetic BB rats is not consistent with normal desaturase activity and may be explained by factors other than desaturation disturbance.     

Plasma acidic glycohydrolases in insulin-dependent diabetes mellitus

Summary We assayed plasma activities of -galactosidase, -hexosaminidase, -mannosidase, -fucosidase and -galactosidase involved in degradation of the glycoprotein molecule in 110 insulin-dependent diabetics aged 3-1/2 to 19 years and compared them to a group of normal youngsters. We correlated the plasma enzyme activities with the duration, control and sequelae of insulin-dependent diabetes. Insulin-dependent diabetics had a significantly higher plasma activity of -hexosaminidase and -mannosidase (p<0.01) and a significantly lower plasma activity of -fucosidase and -galactosidase (p<0.01). Of the 5 enzymes studied, only plasma -hexosaminidase correlated with fasting and postprandial blood sugar (p<0.01), cholesterol and triglycerides (p<0.05). Additionally, poor control of diabetes was also associated with a significantly higher plasma -hexosaminidase activity (p<0.01). Proteinuria or an abnormal Addis count suggestive of renal involvement was associated with various changes in plasma acidic hydrolases. These changes may be related to insulin deficiency rather than hyperglycemia and may be genetically determined.Deceased on August 2, 1981.     

Effects of short-term high dose intake of evening primrose oil on plasma and cellular fatty acid compositions, α-tocopherol levels,and erythropoiesis in normal and Type 1 (insulin-dependent) diabetic men

Summary In addition to their usual diet, nine Type 1 (insulin-dependent) diabetic men and ten male control subjects took 20 g d,ga-tocopheryl acetate enriched evening primrose oil (14.45 g 182c,6, 1.73g 183c,6, 400 mg d,-tocopheryl acetate) daily for one week. At start, diabetic patients had more 140, 150 and 18 2c,6, and less 160, 161c,7, 181c,7, 183c,6, 203c,9, 203c,6, 204c,6 and 226c,3 in plasma, erythrocytes and/or platelets. Furthermore, they had lower 161c,7/160, 181c,7/160, and 204c,6/203c,6 ratios and a higher 203c,6/183c,6 ratio. In diabetic patients, -tocopherol levels in erythrocytes were lower, whereas those in plasma were normal. In both groups, oil intake changed fatty acid profiles. Most markedly, 203c,6 increased, whereas the ratios 203c,6/ 183c,6 and 204c,6/203c,6 decreased. 204c,6 increased in control subjects, but not in diabetic patients. Erythrocytes and platelets responded differently in their fatty acid profiles, -tocopherol rose in plasma and, although less for diabetic patients, in erythrocytes. In diabetic patients as well as in control subjects, erythrocyte count, haemoglobin level, mean corpuscular haemoglobin content and concentration increased and glycosylated haemoglobin percentage decreased without an apparent decline in blood glucose levels. Plasma -thromboglobulin and platelet factor 4 decreased, especially in diabetic patients. In conclusion, diabetic patients had abnormal fatty acid patterns, suggesting an impaired 9, 6 and 5 desaturation and an enhanced chainelongation, and had lower erythrocyte a-tocopherol levels; and short-term high dose intake of evening primrose oil increased 203c,6 in both groups, but 204c,6 only in control subjects, gave fatty acid responses which were different for erythrocytes and platelets, enhanced erythropoiesis, and lowered indices of in vivo platelet activation.     

Mutations in the R-type pyruvate kinase gene and altered enzyme kinetic properties in patients with hemolytic anemia due to pyruvate kinase deficiency

Summary The biochemical properties of erythrocyte pyruvate kinase (PK) together with mutations found in the coding sequence of the R-PK gene in five patients with severe hemolytic anemia due to PK deficiency are described. The enzyme variants were designated PK Mosul (homozygote), PK Bukarest_1,2, PK Hamburg₁, PK Köln₁, and PK Essen (compound heterozygote). PK Mosul showed normal positive cooperative substrate binding, PK Bukarest_1,2 exhibited noncooperative behavior, and PK Hamburg₁ and PK Köln₁ displayed mixed cooperativity, whereas PK Essen was negative cooperative. PK Mosul was found to be homozygous for the mutation 1151 ACG to ATG, resulting in an amino acid substitution 384 Thr to Met. In one allele of PK Bukarest_1,2 a single nucleotide substitution GAG-TAG was found at nucleotide 721, causing a change of 241 Glu to a chain termination codon (PK Bukarest₁). Additionally, in the second allele of this patient a point mutation at position 1594 (CGG-TGG) occurs, changing 532 Arg to Trp (PK Bukarest₂). Direct sequencing showed the heterozygosity of the patient's mother (PK Bukarest₁/normal) at position 721 and of the patient's father (PK Bukarest₂ /normal) at position 1594. A point mutation at position 1529 (CGA-CAA), causing an amino acid substitution 510 Arg-Gln, was identified in PK Hamburg₁ and PK Köln₁. The second mutation in these variants was not detected. In PK Essen no mutation in the coding sequence was found at all. Screening for the mutation at position 1529 in further compound heterozygote patients and in normal subjects of Western European origin showed that this exchange is a common mutation responsible for PK deficiency in this population.Supported by theDeutsche Forschungsgemeinschaft, Grants no. La 527/1 and Ne 416/1.     

Prevention of diabetic glomerulopathy in streptozotocin diabetic rats by insulin treatment

Summary Glomerular basement membrane thickness (GBMT) has been measured in streptozotocin diabetic rats treated with insulin. The study included 3 groups of 8 rats each: 1) a well-controlled group of diabetic rats under insulin treatment with a plasma glucose level reasonable close to normal values, 2) a poorly-controlled group also under insulin treatment with constant high plasma glucose values, and 3) an age and weight matched non-diabetic control group. After 6 months of diabetes, GBMT was measured applying an intercept method on 3 glomerular cross sections from each of the 24 animals. The measurements showed that mean GBMT was 132.2. nm in the non-diabetic control rats and 131.6 nm in the well-controlled diabetic rats. In the poorly-control-led group the mean GBMT was 140.4 nm, i.e. statistically significantly increased when compared to each of the two other groups, 2p=0.022 and 0.012 respectively.The results demonstrate that good blood glucose control in rats preserves normal GBMT.     

Regulation of large coronary vessels by adrenergic mechanisms in conscious dogs

Summary The effects of and adrenergic stimulation were examined in conscious dogs on measurements of left circumflex coronary blood flow and coronary arterial diameter and on calculations of mean coronary resistance (MCR) and left circumflex coronary internal cross-sectional area (CSA). Methoxamine (50 g/kg/min), after transiently increasing left circumflex coronary dimensions, induced sustained reductions in left circumflex coronary diameter (9±2%) and CSA (27±5%) at a time when mean arterial pressure rose by 65±5%, left ventricular (LV) dP/dt had decreased only slightly, and heart rate and mean coronary blood flow were at control levels. Isoproterenol, (0.1 g/kg/min), increased heart rate by 66±8%, LV dP/dt by 58±5%, and CSA by 17±3%, while it decreased mean arterial pressure by 12±1% and MCR by 44±5%. After ₁ adrenergic receptor blockade and with heart rate held constant, isoproterenol did not increase LV dP/dt but decreased mean arterial pressure similarly (13±2%) and induced attenuated increases in CSA (6±1%), and decreases in MCR (17±3%). After combined ₁ and ₂ adrenergic receptor blockades isoproterenol induced no significant effects.Thus, in the conscious dog, large coronary vessels not only react passively to changes in aortic pressure but also undergo substantial active changes. Alpha adrenergic stimulation is sufficiently powerful to reduce CSA, despite the opposing elevation of distending pressure. Moreover, large vessels appear to be regulated by ₁ adrenergic mediated increase in myocardial metabolic demands, as well as by ₂ adrenergic mediated vasodilation.Supported in Part by USPHS Grants HL 15416 and HL 17459     

Low Endogenous Prostaglandin E2 Predisposes to Relapsing Inflammation in Experimental Rat Enterocolitis

Intramural injection ofpeptidoglycan-polysaccharide (PG-PS) induces acuteenterocolitis that spontaneously relapses in Lewis butnot Fischer rats. Interleukin-1 (IL-1) and tumornecrosisfactor- (TNF-) induce prostaglandin E₂(PGE₂) secretion, which inhibits secretion ofthese cytokines by macrophages, suggesting an inhibitoryfeedback mechanism. We postulate that Lewis ratsusceptibility to relapse is due to an imbalance betweenprotective prostaglandins and cytokines. Female Fischerand Lewis rats were injected with PG-PS (37.5 g/g)or human serum albumin intramurally. Tissue IL-1 and PGE₂ immunoreactivities andmyeloperoxidase (MPO) activity were determined.Relapsing rats had lower PGE₂ andPGE₂:IL-1 ratios than nonrelapsingrats (P < 0.05). In Fischer rats, 2 mg/kg/day indomethacinpotentiated cecal MPO and IL-1 concentrationsabove PG-PS alone (P < 0.05). Misoprostol treatmentblocked PG-PS-induced IL-1 and MPO and inhibited the potentiating effect of indomethacin on MPOand IL-1 (P < 0.05). In conclusion, increasedendogenous PG may be protective against relapsinginflammation in PG-PS induced enterocolitis, at least partially via inhibition of proinflammatorycytokines. An imbalance between protectiveprostaglandins and proinflammatory cytokines may beinvolved in the pathogenesis of chronic relapsinginflammation in genetically susceptible hosts.     

In vivo and in vitro test for growth potential of liver cells from rats during early stage of hepatocarcinogenesis by 3′-methyl-4-dimethylaminoazobenzene

Summary A rapid increase in the fraction of small liver cells was observed in the liver of rats during the early stage of hepatocarcinogenesis by 3-methyl-4-dimethylaminoazobenzene (3-Me-DAB). The change in cell population was represented by the decrease in glucose-6-phosphatase activity and by the increase in number of -glutamyltranspeptidase-positive cells. When DNA synthesis of liver cells from rats fed 3-Me-DAB was measured by autoradiography in primary culture, it began to increase 2 weeks after the start of the carcinogen feeding, reaching a plateau level after 3 weeks. Liver cells from rats fed 3-Me-DAB for 2 weeks or over demonstrated a remarkable resistance to the cytotoxic effect of the carcinogen (0.24 mM) in primary culture. Furthermore, liver cells from rats fed 3-Me-DAB for 3 weeks or over proliferated in the presence of the carcinogen in primary culture. When liver cells from 3-Me-DAB-fed and control rats were transplanted into syngeneic rat spleens, the former cells proliferated more vigorously than did the latter. The growth potential of liver cells from 3-Me-DAB-fed rats tended to be enhanced with time in the carcinogen feeding. Hepatocellular carcinomas developed in the host spleens implanted with liver cells from a rat fed 3-Me-DAB for 8 weeks. As described above, liver cells from rats fed 3-Me-DAB demonstrated much greater proliferative ability than normal control cells in vivo and in vitro.Abbreviations used HCC hepatocellular carcinoma - 3-Me-DAB 3-methyl-4-dimethylaminoazobenzene - GGT -glutamyltranspeptidase     

The influence of cardiac cholinergic activation on the induction and maintenace of ventricular fibrillation

Summary The influence of cardiac cholinergic activation was studied in rats and cats on the induction and maintenance of ventricular fibrillation (VF). Acetylcholine (ACH 2–25 g/kg), in doses which did not cause bradycardia or hypotension, induced appearance of spontaneous VF (duration 2–60 sec.) in 9/20 rats which have a high sympathetic autoregulation and in 3/6 cats only, 20–40 secs after the latter had been given adrenaline. ACh (10–45 g/kg) and methacholine (10–40g/kg) also significantly prolonged the fibrillatory period induced electrically in cats and rats with and without atrial or ventricular pacing. The induction or prolongation of VF did not occur when higher doses of ACh (50–100 g/kg) were given to rats. The influence of moderate amounts of cholinergic agents on the heart may be due to localised effects resulting in asynchronous activity. Alternatively, they may produce a discharge of multiple ectopic pacemakers or a disturbance in impulse conduction. Higher doses of ACh depress the S-A and ventricular ectopic activity node thereby decreasing the probability of inducing VF.It is concluded that under conditions of raised cardiac adrenergic activity, a moderate increase in cholinergic influence can both induce and prolong VF. The relevance of these findings to the sudden infant death syndrome is discussed.     

Alterations of GTP-binding Proteins (Gsα and Gq/11α) in Gastric Smooth Muscle Cells from Streptozotocin-Induced and WBN/Kob Diabetic Rats

We investigated possible impairment of the signal transduction system in gastric myocytes of streptozotocin-induced diabetic (STZ) and spontaneous diabetic WBN/Kob (WBN/Kob) rats. Gastric motility 10 weeks after the onset of diabetes mellitus was significantly reduced in both diabetic rats compared with control, and the decreased motility was not recovered by the administration of insulin to maintain normal blood glucose levels. There was no significant difference between both types of diabetic rats and control rats in total number of [³H]quinuclidinyl benzilate ([³H]QNB) binding sites (B _max: 545–587 fmol/mg protein) on gastric smooth muscle cell membranes or in the affinity of [³H]QNB for the binding sites(K _d : 0.06–0.07 nM). Immunoblot analysis using polyclonal anti-G-protein antibodies indicated increased expression of G_s in gastric smooth muscle cell membranes, but no significant change in G_i or G_q/₁₁ expression in STZ rats, and decreased expression of G_q/₁₁ with no significant change in G_s and G_i in WBN/Kob rats. The cAMP production in gastric smooth muscle cell membranes was augmented in the absence and presence of 100 M isoproterenol, and 100 M forskolin in STZ rats, whereas no significant change of cAMP production was observed in WBN/Kob rats irrespective of the presence of the stimulants. These findings suggest that long-standing diabetes may induce alterations in signal transduction at downstream receptors in gastric myocytes, resulting in the impairment of gastric motility, although the mechanism of reduced contractile activity may differ between STZ and WBN/Kob rats.     

Role of histamine H3 receptors in control of mouse intestinal motility in vivo and in vitro: comparison with alpha2-adrenoceptors

We tested drugs acting at histamine H₃ receptors in mice on the gastrointestinal transit of a charcoal meal in vivo and on neurogenic contractions of isolated ileal preparations. The agonist (R)--methylhistamine (100 mol/kg) caused a maximum 25% reduction of gastrointestinal transit, an effect mimicked by immepip (100 mol/kg) and antagonized by thioperamide (20 mol/kg) or clobenpropit (20 mol/kg). In the isolated ileum, (R)--methylhistamine (10–100 M) caused a slight, thioperamide-insensitive, reduction (maximum 15%) of electrically evoked cholinergic contractions. In comparison, the ₂-adrenoceptor agonist clonidine (0.1 mol/kg) caused a 35.2% inhibition of the gastrointestinal transit and almost completely reduced (maximum 82% at 1 M) the cholinergic contraction of the isolated ileum, both effects being antagonized by idazoxan (0.4 mol/kg and 1 M, respectively). These results suggest that histamine H₃ receptors, located outside the myenteric plexus, mediate an inhibition of the gastrointestinal transit in vivo. Conversely, the presence of ₂-adrenoceptors in the cholinergic nerve endings and their inhibitory role in the control of gastrointestinal propulsion is confirmed.     

Intestinal mucin secretion in streptozotocin-diabetic rats

In diabetic rats, intestinal mucin secretion is unusually high compared with that in normal rats. These studies demonstrate that mucin synthesis is also increased in the diabetic intestine. - and -adrenergic agonists or antagonists did not affect mucin output in either normal or diabetic animals, suggesting that altered release in diabetes was not due to goblet cells responding abnormally to adrenergic agents. The cholinergic agonist bethanechol caused a dose-dependent and atropine-sensitive increase in mucin secretion from the normal intestine but had no effect on mucin release from diabetic tissue. Atropine alone did not reduce mucin secretion from the diabetic intestine to levels found in normal tissue. Cholera toxin caused an approximately fivefold increase in mucin output from normal rats but had no effect on mucin secretion from diabetic animals. Thus, goblet cell responses to cholinergic stimulation and cholera toxin in the diabetic intestine are markedly impaired. However, loss of cholinergic control does not appear to be responsible for altered baseline mucin secretion in diabetes.This work was supported by the Medical Research Council of Canada. M.M. holds a Scholarship Award and J.S.D. a Professorship from the Alberta Heritage Foundation for Medical Research.     

Nitric oxide-mediated neurotransmission is attenuated in the anococcygeus muscle from diabetic rats

Summary The effect of STZ-induced diabetes of 8-weeks duration was examined on nitric oxide-mediated neurotransmission in the rat anococcygeus muscle. In the presence of noradrenergic blockade and raised tissue tone, relaxant responses to nerve stimulation (0.5–5 Hz, for 10 s), sodium nitroprusside (5 and 10 nmol/l) and nitric oxide (1 and 3 mol/l) were significantly reduced in anococcygeus muscles from diabetic rats compared to responses from control rats (p <0.05). In contrast, relaxations to papaverine (3 and 10 mol/l were not reduced in tissues from diabetic rats. The nitric oxide synthesis inhibitor NOLA (100 mol/l) abolished relaxant responses to nerve stimulation but had no effect on responses to any of the relaxant agents used. Exposure to NOLA at 10 mol/l reduced stimulation-induced relaxations; this reduction was significantly greater in tissues from the diabetic group than from the control group (p <0.05), probably as a consequence of the smaller relaxant responses in muscles from diabetic rats. Contractile responses to nerve stimulation (1–10 Hz, for 10 s), but not noradrenaline (0.03–30 mol/l), were significantly greater in anococcygeus muscles from diabetic rats than from control rats (p <0.05). NOLA (100 mol/l) significantly enhanced stimulation-induced contractions (p <0.05), however the enhancement was significantly less in tissues from diabetic rats (p <0.05). The results suggest that STZ-induced diabetes impairs smooth muscle reactivity to nitric oxide in the rat anococcygeus muscle.Abbreviations STZ Streptozotocin - NOLA N^G-nitro-l-arginine - NANC nonadrenergic noncholinergic - ANOVA analysis of variance     

Interactive influences of peroxisome proliferator-activated receptor α activation and glucocorticoids on pancreatic beta cell compensation in insulin resistance induced by dietary saturated fat in the rat

Aims/hypothesis We sought to elucidate whether excess glucocorticoids and increased dietary lipids act synergistically to impair glucose tolerance and, if so, whether activation of peroxisome proliferator-activated receptor (PPAR) has an adverse or beneficial effect on glucose tolerance.Methods Dexamethasone (100 g kg^–1 body weight day^–1; 5 days) was administered to insulin-resistant rats fed a high-saturated-fat (HF) diet for 4weeks. The PPAR agonist WY14643 was administered (50 mg kg^–1 body weight intraperitoneally) 24 h before sampling. Glucose-stimulated insulin secretion (GSIS) was assessed in vivo after an acute glucose bolus injection, and in vitro using step-up and step-down islet perifusions.Results Although neither PPAR activation nor dexamethasone alone affected fasting glycaemia in the HF group, dexamethasone in combination with PPAR activation elicited marked postabsorptive hyperglycaemia. Dexamethasone treatment of HF rats had little effect on GSIS after an acute glucose challenge in vivo, but induced glucose intolerance. PPAR activation augmented GSIS in dexamethasone-treated HF rats in vivo, restoring glucose tolerance. Contrasting with data obtained in vivo, greatly enhanced peak rates of GSIS were observed ex vivo in perifusions of islets from dexamethasone-treated HF rats compared with those from untreated HF rats, an effect attenuated by antecedent PPAR activation.Conclusions/interpretation The study demonstrates that glucocorticoid excess precipitates the development of glucose intolerance in rats maintained on a high-saturated-fat diet. It does this by interrupting the negative feedback loop between insulin sensitivity and secretion in vivo, such that further enhancement of compensatory insulin secretion is not possible. PPAR activation restores the coupling between insulin secretion and action.     

Effect of Interferon-α Treatment of Chronic Hepatitis C on Health-Related Quality of Life

Studies of interferon- (IFN-)therapy for chronic hepatitis C have focused on viralclearance; however, few have evaluated patient'shealth-related quality of life during therapy. Thisstudy evaluates health-related quality of life and theprevalence of anxiety and depression in patients withchronic hepatitis C before, during, and followingIFN- therapy. Patients undergoing IFN-therapy for chronic hepatitis C were asked to completehealth status measures as well as anxiety and depressioninventories before, during, and following IFN-therapy. These measures were compared to the results of healthy adults in the general US population.Thirty-eight of forty-eight eligible patients (79%) withchronic hepatitis C completed the questionnaires.Respondents demonstrated a significant increase in depression during the sixth month ofinterferon therapy in comparison to pretreatmentresults. Anxiety scores improved significantly after onemonth of IFN- in comparison to pretreatmentresults. Scores on the health status measures did notvary with IFN- therapy. Patient responses wereanalyzed with respect to biochemical response(normalized transaminases) to IFN-. IFN-responders, who were aware of their transaminase results,exhibited lower scores on anxiety subscales during andafter therapy (P = 0.02-0.04). Scores on the healthstatus subscale, role emotional, improved in IFN- responders compared to nonresponders during thesixth month of therapy (P = 0.02). Response toIFN- therapy was not associated with any otherdifferences on subscale analysis. Patients with chronichepatitis C exhibited health perceptions similar to thegeneral US population, and these were unchanged duringIFN- therapy. However, the incidence ofdepression significantly increased during the sixthmonth of IFN- therapy. IFN- respondersexhibited fewer emotional problems as well as a lowerincidence of anxiety during and followingtherapy.     

Investigations on metabolism,genotoxic effects and carcinogenicity of 2,2′-dichlorodiethylether

Summary Either 40 mole or 160 mole 2,2-DDE was injected into male Wistar rats and the metabolites, TdGA and HEMA, were determined in the 24-h urine specimens. Comparative investigations were carried out giving equimolar amounts of chloroethanol and 2-chloroacetaldehyde diethyl acetal. In a further step, inhalation experiments were performed to determine urinary excretion of the two metabolites after an 8-h exposure of male Wistar rats to 10, 50, 100, and 500 ppm 2,2-DDE and to 50, 200, und 1000 ppm vinyl chloride.A long-term study was conducted to investigate the possible carcinogenicity of 2,2-DDE in male and female Sprague-Dawley rats following s.c. injections of 4.36 mole and 13.1 mole 2,2-DDE in DMSO per week. The evaluation of tumor development in treated groups and controls were based on macroscopic inspection and histological examinations of the suspect organs and tissues.Analysis of the metabolites showed that HEMA excretion was much lower than the excretion of TdGA following the uptake of 2,2-DDE, 2-chloroethanol and 2-chloroacetaldehyde diethyl acetal. Contrary to these, vinyl chloride uptake resulted in a higher urinary excretion of HEMA than TdGA.There was no appreciable increase in the number of tumors detected in 2,2-DDE-treated animals when compared with untreated or DMSO-treated groups.Since irradiation of 2,2-DDE with UV did not elevate mutagenic activity of the compound against Salmonella typhimurium TA100, the high mutagenicity of the compound found in a desiccator cannot be due to the liberation of mutagenic compounds produced under the influence of UV light.Abbreviations 2,2-DDE 2,2-dichlorodiethylether - DMSO dimethylsulfoxide - HEMA hydroxyethyl mercapturic acid - TdGA thiodiglycolic acid     

Pentadecapeptide BPC 157 Interactions with Adrenergic and Dopaminergic Systems in Mucosal Protection in Stress

Since superior protection against differentgastrointestinal and liver lesions and antiinflammatoryand analgesic activities were noted for pentadecapeptideBPC (an essential fragment of an organoprotective gastric juice protein named BPC), thebeneficial mechanism of BPC 157 and its likelyinteractions with other systems were studied. Hence itsbeneficial effects would be abolished by adrenal glandmedullectomy, the influence of different agents affecting, , and dopamine receptors on BPC 157gastroprotection in 48 h restraint stress was furtherinvestigated. Animals were pretreated (1 hr beforestress) with saline (controls) or BPC 157 (dissolved insaline) (10 g or 10 ng/kg body wt intraperitoneallyor intragastrically) applied either alone to establishbasal conditions or, when manipulating the adrenergic or dopaminergic system, a simultaneousadministration was carried out with various agents withspecific effects on adrenergic or dopaminergic receptors[given in milligrams per kilogram intraperitoneally except for atenolol, which was givensubcutaneously] phentolamine (10.0), prazosin (0.5),yohimbine (5.0), clonidine (0.1) (-adrenergicdomain), propranolol (1.0), atenolol (20.0)(-adrenergic domain), domperidone (5.0), and haloperidol(5.0) (peripheral/central dopamine system).Alternatively, agents stimulating adrenergic ordopaminergic systemsadrenaline (5.0) or bromocriptine(10.0)-were applied. A strong protection, noted followingintragastric or intraperitoneal administration of BPC157, was fully abolished by coadministration ofphentolamine, clonidine, and haloperidol, andconsistently not affected by prazosin, yohimbine, ordomperidone. Atenolol abolished only intraperitoneal BPC157 protection, whereas propranolol affectedspecifically intragastric BPC 157 protection.Interestingly, the severe course of lesion developmentobtained in basal conditions, unlike BPC 157gastroprotection, was not influenced by the applicationof these agents. In other experiments, when adrenalineand bromocriptine were given simultaneously, a strong reductionof lesion development was noted. However, when appliedseparately, only adrenaline, not bromocriptine, has aprotective effect. Thus, a complex protectiveinteraction with both -adrenergic (e.g.,catecholamine release) and dopaminergic (central)systems could be suggested for both intragastric andintraperitoneal BPC 157 administration. The involvementof -receptor stimulation in BPC 157 gastroprotection appearsto be related to the route of BPC 157 administration.The demonstration that a combined stimulation ofadrenergic and dopaminergic systems by simultaneous prophylactic application of adrenaline(- and -receptor stimulant) andbromocriptine (dopamine receptor agonist) maysignificantly reduce restraint stress lesionsdevelopment provides insight for further research on the beneficial mechanism ofBPC 157.     

Changes in the activity of ‘active’ pyruvate dehydrogenase complex in the newborn of normal and diabetic rats

Summary At birth, hepatic active and dichloracetate-activated pyruvate dehydrogenase complex activities in the newborn of normal, mildly diabetic, and severely diabetic rats were similar. The active and dichloracetate-activated pyruvate dehydrogenase complex activities increased significantly during the first 2 and 6 postnatal h, respectively in the three groups of neonates (p<0.05). The greatest increase in both active and dichloroacetate-activated pyruvate dehydrogenase complex activity was observed in the neonates of mildly diabetic rats. Administration of glucose or insulin at birth to the newborn of normal rats caused a significant increase in the percentage of active pyruvate dehydrogenase complex activity within 1 h (p<0.01). Similar treatment caused no significant increases in the newborn of severely diabetic rats. The transient increases in active pyruvate dehydrogenase complex activity in the neonates of normal and diabetic rats were consistent with rapid disappearance of blood lactate during the first hours of postnatal life.     

Autonomic responses and neurohumoral control in the human early antenatal heart

Summary Previous sporadic findings and the results of recent, more systematic studies now permit us to make an attempt to outline the contribution of the sympathetic and parasympathetic system to the control of the human early antenatal cardiac function. In the developing heart of man, only acetylcholine and catecholamines have so far been proven to act as true autonomic transmitters. Muscariniccholinergic responses to acetylcholine and related agents can be detected from the 4th postconception week onwards, i.e. soon after the initiation of the first heartbeats. The same applies to the -adrenergic responsiveness to noradrenaline, adrenaline and other adrenergic stimulants in a somewhat later period, commencing at week 5 after conception. The maximum cardiac response to all these agonists becomes stronger as development continues. — Evidence is accumulating to suggest that prostaglandins and triiodothyronine might modulate the regulatory function of autonomic transmitters in the human early antenatal heart.Morphological and functional establishment of the autonomic innervation occurs in the human heart well after the appearance of the reactivity to autonomic transmitters. Under in vitro conditions, muscarinic-cholinergic neuro-effector transmission can be demonstrated in 10–12-week-old hearts, and cardiac -adrenergic transmission can first be detected in weeks 13–14. From these observations and from the appearance of the in utero fetal tachycardiac response to atropine in weeks 15–17 and the bradycardiac response to -blockers in weeks 23–28, it seems that the parasympathetic-cholinergic control of the developing human heart becomes functional and can play a role in the overall regulation of the antenatal cardiac function carlier than the sympathetic-adrenergic neural control. In the period before the onset of sympathetic neural control, the adrenergic regulation of the antenatal heart is achieved predominantly through the extra-adrenal (mainly the para-aortic) chromaffin tissues, whereas the co-operative function of the adrenal medulla becomes effective later in fetal life.     

Enzymatic determination of serum 3α-sulfated bile acids concentration with bile acid 3α-sulfate sulfohydrolase

A newly developed enzymatic method for determining urinary 3-sulfated bile acids was used to measure serum 3-sulfated bile acid levels in 114 patients with hepatobiliary diseases and 56 healthy subjects. The lowest measurable amount of the 3-sulfated bile acids was 0.5 µmol/liter. The standard curves for glycolithocholic acid 3-sulfate, glycoursodeoxycholic acid 3-sulfate, and lithocholic acid 3-sulfate were linear from 0.5 to 250 µmol/liter. Specificity of the assay was satisfactory and intra- and interassay variations ranged from 0.8 to 4.4% and from 1.2 to 7.9%, respectively. Analytical recovery was more than 91%. The values obtained by this assay were well correlated with those by gas-liquid chromatography measurement (r=0.91,P<0.01). The fasting serum 3-sulfated bile acids level in healthy subjects ranged from undetectable to 1.9 µmol/liter (mean±se; 0.9±0.1 µmol/liter). The percentage of 3-sulfated bile acids in total bile acids (sum of 3-sulfated and 3-hydroxy bile acids) in serum was 16.8±1.5%. In subjects with hepatobiliary diseases, serum 3-sulfated bile acids levels were elevated; however, the percentage of 3-sulfated bile acids in total bile acids was decreased and correlated with the severity of hepatocellular insufficiency. This enzymatic assay is simple, rapid, and accurate for the determination of serum 3-sulfated bile acids.