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G Sager

Publications and source records attributed to G Sager.

At least 19 recordsLinked to original sources
PubMed2005

Effects of acute hypercalcaemia on blood pressure in subjects with and without parathyroid hormone secretion.

AIM: Acute hypercalcaemia increases the blood pressure, but the mechanism is uncertain. It may partly be the result of the concomitant fall in parathyroid hormone (PTH) secretion as PTH has been reported to have a vasodilator effect. To elucidate this, we infused calcium intravenously in subjects with and without PTH secretion. METHODS: Seven thyroparathyroidectomized subjects with undetectable PTH levels and 10 controls were studied twice, once with a calcium clamp technique that increased plasma ionized calcium in two steps of 0.1 mmol L(-1), each step lasting 60 min, and once with a placebo infusion. RESULTS: On the placebo day, blood pressure and all other variables were unaffected in both groups. On the calcium day, systolic blood pressure increased gradually and significantly from end of baseline till end of the calcium infusion in the controls (123.5 +/- 19.8 and 134.2 +/- 17.6 mmHg, P < 0.004) but not in the thyroparathyroidectomized subjects (124.9 +/- 15.7 and 126.0 +/- 20.6 mmHg, P = ns). Serum PTH levels fell promptly in the controls, and in both groups there was a significant increase in serum phosphate. The diastolic blood pressure and pulse rate, and the plasma adrenaline and noradrenaline, plasma renin activity, and serum aldosterone levels were unaffected by the calcium infusion. CONCLUSION: During acute hypercalcaemia the blood pressure increase appears unrelated to catecholamine secretion and the renin-aldosterone system, whereas the fall in PTH secretion may play a contributory role.

Adult↗
PubMed2004

Reconstitution of ATP-dependent cGMP transport into proteoliposomes by membrane proteins from human erythrocytes.

The cellular efflux of cGMP from human erythrocytes has previously been characterized in functional studies. The purpose of the present study was to find membrane proteins with the ability to restore ATP-dependent uptake of cGMP into proteoliposomes. Human erythrocyte membranes were solubilized with CHAPS (3-([3-cholamidopropyl]dimethylammonio)-1-propanesulfonate) and gel filtration gave three protein fractions with the ability to restore active transport. Only two of these fractions were retained on a lentil lectin column. By using these two purification steps, active transport was 11 times higher in the first fraction compared to the original material and SDS-PAGE showed the presence of proteins with sizes of 145 kDa and 165 kDa. The second fraction gave 20 times higher active transport after purification and comprised proteins with sizes of 145 kDa and 180 kDa. At present three members of the MRP (multi-resistance associated protein) family have been detected in human erythrocytes: MRPI, MRP4 and MRP5. The last two proteins have been shown to transport cyclic nucleotides. The present findings are compatible with MRP4 as the 145 kDa protein, MRP5 as the 165 kDa protein and MRP1 as the 180 kDa protein. However, the 145 kDa protein could also be SMRP (short multi-resistance protein), the gene splice variant of MRP5. Immunoprecipitation of MRP5 from CHAPS-solubilized extract reduced active transport and specific binding by about 45% and 40%, respectively. This shows that MRP5 is an important cGMP-transporting protein in human erythrocytes.

Adenosine Triphosphate↗
PubMed2002

[Prevalence of anaemia in pregnancy and analysis of the underlying factors].

OBJECTIVE: To determine the prevalence of anaemia and to evaluate the factors that condition its occurrence.Setting. Out-patient clinics in the La Plata area, Buenos Aires, Argentina. DESIGN: Observational and prospective study. PARTICIPANTS: All the pregnant women consulting for the first time, excluding those with prior pathology or regular use of medical drugs. MEASUREMENTS: Anaemia was defined at values of Hb < 11 g/dl. Questionnaires were administered for general data and the type of nutrition, and a complete haematological report was compiled. RESULTS: 1218 pregnant women started the study. Anaemia was detected in 196 of them (16%), with average Hb 9.88 g/dl. Between normal and anaemic pregnant women, the following differences were found between the first and second consultations: weight (64.44 vs 59.50, p < 0.00001), family income (US$744.36 vs 568.28, p < 0.0001), kilocalories ingested (2,488.44 vs 2,204.28, p = 0.01), percentage of proteins in diet (15.73 vs 13.69, p = 0.002), and weekly iron consumption (15.24 mg vs 13.04, p < 0.0001). CONCLUSIONS: Pregnant women run a greater risk of suffering anaemia if they have diets of < 1800 kcal, < 13% proteins, less than 7 mg of iron per week, and haemic iron < 10%; and family income below US$400. Ensuring a proper diet and improving the social and economic conditions of this population group will reduce the risk of anaemia during pregnancy and its perinatal consequences.

Adult↗
PubMed2001

Inhibition by guanosine cyclic monophosphate (cGMP) analogues of uptake of [(3)H]3',5'-cGMP without stimulation of ATPase activity in human erythrocyte inside-out vesicles.

The cellular extrusion of guanosine 3',5'-cyclic monophosphate (3',5'-cGMP) is a unidirectional ATP-dependent process that is inhibited by probenecid, a non-selective transport inhibitor of organic anions. In the present study, various cGMP analogues were tested for their ability to inhibit 3',5'-cGMP efflux and stimulate the cGMP-selective ATPase in human erythrocytes. The difference in uptake of 1 microM [(3)H]3',5'-cGMP to inside-out vesicles in the presence and absence of 1 mM ATP at 37 degrees was defined as active transport. Two ATP-dependent components were detected for unlabelled 3',5'-cGMP (0.01--100 microM) with respective K(i) of 1.3 +/- 0.2 and 280 +/- 50 microM (mean +/- SEM, N = 3). The high-affinity transport was inhibited by the analogues with a typical pattern: Rp-monophosphorothioate guanosine 3',5'-cyclic monophosphate (Rp-cGMPS) > 3',5'-cGMP > 2'-O-monobutyryl guanosine 3',5'-cyclic monophosphate (O-mb-cGMP) approximately N(2)-monobutyryl guanosine 3',5'-cyclic monophosphate (N-mb-cGMP) > or = N(2),2'-O-dibutyryl guanosine 3',5'-cyclic monophosphate (Db-cGMP) approximately 8'-bromo guanosine 3',5'-cyclic monophosphate (Br-cGMP) approximately Guanosine 2',3'-cyclic monophosphate (2'3'-cGMP) > Sp-monophosphorothioate guanosine 3',5'-cyclic monophosphate (Sp-cGMPS). A concentration-dependent inhibition was found for the low-affinity transport, but no distinct order of potency was identified. Analysis according to Lineweaver--Burk of active [(3)H]3',5'-cGMP transport (0.2--2 microM) gave a K(m) value of 1.5 +/- 0.1 microM (mean +/- SEM, N = 3). The presence of 10 microM cGMP analogues did not change the ordinate intercept, but made the slopes steeper with a typical order: Rp-cGMPS > 3',5'-cGMP > N-mb-cGMP approximately O-mb-cGMP approximately db-cGMP approximately 8-Br-cGMP > 2',3'-cGMP > Sp-cGMPS. Only 3',5'-cGMP and 2',3'-cGMP were able to activate the cGMP-specific ATPase, 640 +/- 200% and 430 +/- 160% (mean +/- SEM, N = 5) above basal levels, respectively. The present data show that the binding is less selective than ATPase activation of the cellular cGMP transport system.

Adenosine Triphosphatases↗
PubMed2001

An iron-regulated ferric reductase associated with the absorption of dietary iron.

The ability of intestinal mucosa to absorb dietary ferric iron is attributed to the presence of a brush-border membrane reductase activity that displays adaptive responses to iron status. We have isolated a complementary DNA, Dcytb (for duodenal cytochrome b), which encoded a putative plasma membrane di-heme protein in mouse duodenal mucosa. Dcytb shared between 45 and 50% similarity to the cytochrome b561 family of plasma membrane reductases, was highly expressed in the brush-border membrane of duodenal enterocytes, and induced ferric reductase activity when expressed in Xenopus oocytes and cultured cells. Duodenal expression levels of Dcytb messenger RNA and protein were regulated by changes in physiological modulators of iron absorption. Thus, Dcytb provides an important element in the iron absorption pathway.

Amino Acid Sequence↗
PubMed2001

Methylene blue reduces lung fluid filtration during the early phase of endotoxemia in awake sheep.

OBJECTIVE: To determine whether methylene blue (MB), an inhibitor of soluble guanylate cyclase and nitric oxide synthase, alters lung hemodynamics and fluid filtration after endotoxin in sheep. DESIGN: Prospective, randomized, controlled experimental study with repeated measurements. SETTING: University animal laboratory. SUBJECTS: Eight yearling, awake sheep. INTERVENTIONS: Sheep were instrumented for a chronic study with vascular and lung lymph catheters. In two experiments, separated by 1 wk of recovery, the animals received intravenously either an injection of MB 10 mg/kg or a corresponding volume of 0.9% sodium chloride as pretreatment. Thirty minutes later, sheep received a bolus injection of Escherichia coli endotoxin 1 microg/kg, followed by either an infusion of MB 2.5 mg/kg/hr or a corresponding volume of 0.9% sodium chloride for 5 hrs. MEASUREMENTS AND MAIN RESULTS: MB decreased the early phase endotoxin-induced rises in pulmonary capillary pressure and pulmonary vascular resistance. MB also reduced the increments in lung lymph flow (QL) and protein clearance (CL) as well as the rightward shift of the permeability-surface area product (PS). In addition, MB diminished the decrease in cardiac output, stabilized mean arterial pressure, and precluded the rise in plasma and lung lymph cyclic guanosine 3'-5' monophosphate. However, during the late phase, MB-treated sheep presented with a faster rise in QL with no difference in CL and PS from the endotoxemic controls. CONCLUSIONS: During the early phase of endotoxemia in sheep, MB attenuates lung injury by decreasing the enhanced lung fluid filtration as a result of reduced pulmonary capillary pressure and permeability. However, MB does not counteract the late phase increase in lung fluid filtration.

Animals↗
PubMed2000

ATPase activity and transport by a cGMP transporter in human erythrocyte ghosts and proteoliposome-reconstituted membrane extracts.

We previously described the [(3)H]cGMP-binding characteristics of a CHAPS-solubilized protein that we proposed to be a cGMP transporter. We now report the ATPase activity of the membrane-bound, solubilized and reconstituted form of a cGMP transporter. The membrane-bound protein of unsealed ghosts had a linear ATPase activity over a 120 min incubation period with optimal activity of about 400 pmol/mg/min. The apparent K(m) and V(max) for ATP were about 0.5 mM and 300 pmol/mg/min, respectively. When solubilized with CHAPS the specific activity of the protein was reduced to about 70 pmol/mg/min. Reconstitution of the CHAPS preparation into phospholipid bilayer using rapid detergent removal by Extracti-gel column resulted in proteoliposomes which had ATPase activity similar to that found in the erythrocyte membranes. The proteoliposomes displayed a linear ATP-dependent uptake of [(3)H]cGMP with an apparent K(m) value of 1. 0 microM. This low K(m)-uptake of [(3)H]cGMP in proteoliposomes was not affected by 10 microM of AMP, cAMP and GMP, but was completely abolished in the presence of the non-hydrolyzable ATP analogue, ATP-gamma-S. Some ATPase activation was also observed in the presence of 2 microM cAMP, but it is unclear whether this activity was coupled to the cGMP transporter. Our results show that the membrane protein responsible for cGMP transport has an ATPase activity and transports the cyclic nucleotide in the presence of ATP.

ATP-Binding Cassette Transporters↗
PubMed2000

Leukotriene C(4) (LTC(4)) does not share a cellular efflux mechanism with cGMP: characterisation of cGMP transport by uptake to inside-out vesicles from human erythrocytes.

The transport of cGMP out of cells is energy requiring and has characteristics compatible with an ATP-energised anion pump. In the present study a model with inside-out vesicles from human erythrocytes was employed for further characterisation of the cGMP transporter. The uptake of leukotriene C(4) (LTC(4)), a substrate for multidrug resistance protein (MRP), was concentration-dependently inhibited by the leukotriene antagonist MK571 (IC(50)=110+/-20 nM), but cGMP was unable to inhibit LTC(4) uptake. Oxidised glutathione (GSSG) and glutathione S-conjugates caused a concentration-dependent inhibition of [(3)H]cGMP uptake with IC(50) of 2200+/-700 microM for GSSG, 410+/-210 microM for S-(p-nitrobenzyl)glutathione and 37+/-16 microM for S-decylglutathione, respectively. Antioxidants such as reduced glutathione and dithiothreitol did not influence transport for concentrations up to 100 microM, but both inhibited cGMP uptake with approx. 25% at 1 mM. The cGMP pump was sensitive to temperature without activity below 20 degrees C. The transport of cGMP was dependent on pH with maximal activity between pH 8.0 and 8.5. Calcium caused a concentration-dependent inhibition with IC(50) of 43+/-12 microM. Magnesium gave a marked activation in the range between 1 and 20 mM with maximum effect at 10 mM. The other divalent cations, Mn(2+) and Co(2+), were unable to substitute Mg(2+), but caused some activation at 1 mM. EDTA and EGTA stimulated cGMP transport concentration-dependently with 50% and 100% above control at 100 microM, respectively. The present study shows that the cGMP pump has properties compatible with an organic anion transport ATPase, without affinity for the MRP substrate LTC(4). However, the blockade of the cGMP transporter by glutathione S-conjugates suggests it is one of several GS-X pumps.

Adenosine Triphosphate↗
PubMed2000

Evidence of dysfunctional beta2-adrenoceptor signal system in pre-eclampsia.

OBJECTIVES: To determine how beta2-adrenoceptor binding and function differ between healthy women and those with pre-eclampsia. DESIGN: Case-control study. SETTING: Faculty of Medicine, University of Tromsø, Norway. PARTICIPANTS: Two groups of pregnant women: eight cases with pre-eclampsia, matched with eight healthy controls. METHODS: Venous blood was drawn from women in both groups after an overnight rest. The two groups were matched for gestational age which was (mean (SD)) 36 x 4 (3 x 8) and 36 x 5 (4 x 4) weeks for the pre-eclamptic and control groups, respectively. Six weeks after delivery a second blood sample was obtained. The binding and function of beta2-adrenoceptors were determined in isolated human mononuclear leukocytes. The levels of adrenaline and noradrenaline were determined in plasma from venous blood. RESULTS: An elevated density of functional beta2-adrenoceptors was observed in normal pregnancy [mean (SD) 390 (90) vs 270 (60) sites/cell postpartum], due to an increased fraction of receptors in high affinity state, with unaltered total receptor density. The number of functional beta2-adrenoceptors was reduced in pre-eclampsia [mean (SD) 80 (40) vs 240 (30) sites/cell postpartum], due to a reduction in the total receptor number with an unaltered fraction of high affinity receptors. In pregnancy, both unstimulated and isoprenaline-stimulated cAMP levels were reduced in the women with pre-eclampsia (0 x 5 (0 x 2) and 1 x 7 (0 x 9) pmol/10(6) cells, respectively) compared with the normal pregnant controls (mean (SD) 1 x 2 (0 x 3) and 4 x 7 (1 x 8) pmol/10(6) cells, respectively). Plasma catecholamine levels were not elevated in the women with pre-eclampsia. CONCLUSIONS: The increased number of functional beta2-adrenoceptors may contribute to the vasodilatation seen in normal pregnancy, while the reduced overall number of receptors may be one of several factors that account for increased peripheral vascular resistance in pre-eclampsia.

Adrenergic beta-Agonists↗
PubMed1999

Elimination of methoxyacetic acid and ethoxyacetic acid in rat.

1. The pharmacokinetics of methoxyacetic acid (MAA) and ethoxyacetic acid (EAA) have been determined in the male and female rat following bolus intravenous administration at 100 mg/kg. The plasma-concentration data of MAA fitted well to a one-compartment model, and the plasma-concentration data of EAA to a two-compartment model. 2. The elimination half-life of MAA estimated from plasma data was higher in females (18.6+/-2.0 h) than in males (13.2+/-0.4 h). There was no difference in the elimination half-lives estimated from urine data. The apparent volume of distribution was lower in the male than in the female rat estimated from plasma data only, while AUC, total and non-renal clearances and the relative amount MAA excreted unchanged in urine was similar in the male and female rat. 3. Clearance of EAA is higher than of MAA, and this appears as a result of metabolic capacity. The elimination half-lives of EAA were similar in the male and female rat, 9.4+/-3.7 and 10.5+/-2.6 h respectively. AUC was higher in the female compared with the male rat. The fraction of EAA eliminated during the distribution phase was 44.0+/-15.4 and 41.0+/-17.4% in the male and female rat respectively. The initial volume of distribution, the apparent volume of distribution, total and non-renal clearance are higher in the male compared with the female rat.

Acetates↗
PubMed1998

[Mechanisms behind drug dependence].

The neurobiological mechanisms involved in the development and maintenance of drug dependency are reviewed and discussed. Whereas physical dependency is related to abstinence symptoms with a noradrenergic hyperactivity in locus ceruleus, motivational dependency is related to euphoria, which correlates with dopaminergic activity in the mesolimbic pathway, especially in nucleus accumbens. Despite the fact that many addictive drugs are chemically unrelated, they increase the extracellular levels of dopamine in nucleus accumbens. This has been observed with cocaine, amphetamine, ecstacy, nicotine, opiates, ethanol, and cannabinoids. On the other hand, substances like LSD do not appear to influence the dopamine level in the mesolimbic pathway. Increasing knowledge about how drug abuse modulates signal pathways in discrete parts of the brain gives a new insight into the development and maintenance of drug dependency.

Cannabinoids↗
PubMed1998

Cyclic AMP stimulates the cyclic GMP egression pump in human erythrocytes: effects of probenecid, verapamil, progesterone, theophylline, IBMX, forskolin, and cyclic AMP on cyclic GMP uptake and association to inside-out vesicles.

The knowledge about the structure and function of the protein families responsible for cGMP synthesis and metabolic conversion has grown vastly the last years, whereas little is known about proteins that account for the cellular export of cGMP. In the present study, we have employed a model with inside-out vesicles prepared from human erythrocytes to characterize modulation and regulation of cellular cGMP extrusion. The active transport was saturable (Km of 2.4 +/- 0.2 microM, mean +/- SEM, n = 3) and coupled to ATP hydrolysis since no accumulation was detected in the presence of ATP-gamma-S and AMP-PNP. The observation that 100 microM of cAMP caused a minimal inhibition (14.4 +/- 0.3%) of active cGMP transport showed that the extrusion system for cGMP was not shared with cAMP, but a competitive interaction occurred for the ATP-independent association to the inside out vesicles. In contrast, the lowest, but physiological relevant cAMP concentrations (0.1-5 microM) stimulated the active cGMP transport with 30-35%, an observation that suggests cAMP as an allosteric regulator of the cGMP transporter. Several well-known modulators of other energy-requiring membrane transport systems caused a competitive and concentration-dependent inhibition, including verapamil (Ki = 13.0 +/- 2.4 microM), forskolin (Ki = 13.5 +/- 1.4 microM) and probenecid (Ki = 27.0 +/- 1.3 microM). Progesterone, which was the most potent inhibitor (Ki = 2.2 +/- 0.3 microM), interacted with the active cGMP transport in a noncompetitive manner. The highest concentration (100 microM) of IBMX and theophylline reduced the active cGMP uptake with 29.5 +/- 1.9% and 21.6 +/- 2.1%, respectively. None of these substances interfered with the association of cGMP to the vesicles in absence of ATP. The present results show that human erythrocytes possess a cell membrane cGMP transporter which is coupled to an ATPase. Its activity is regulated by cAMP in an apparent allosteric manner and inhibited by substances previously known to interact with other membrane transport systems.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Urinary levels of cyclic guanosine monophosphate (cGMP) in patients with cancer of the uterine cervix: a valuable prognostic factor of clinical outcome?

Changes in urinary cyclic nucleotide levels have been reported in patients with various types of cancers. The present study was conducted to relate changes in urinary levels of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) to the clinical outcome of 11 patients treated for cancer of the uterine cervix. Urine was sampled for 24 h before and 3 months after primary treatment. The levels of cGMP increased in all the patients (n = 5) who relapsed within the observation period of 39 months. 4 of these patients showed an increased cGMP/cAMP ratio. In the patients without relapse (n = 6), the cGMP levels decreased, whereas the cGMP/cAMP ratios were unchanged. No marked changes in the levels of cAMP were observed for either of the groups. The measurement of urinary cGMP levels seems to be a valuable tool in the follow-up of patients with cancer of the uterine cervix.

Adult↗
PubMed1998

Changes in fibrinolytic activity in diving grey seals.

In order to test the hypothesis that enhanced fibrinolytic activity is a factor which prevents the blood of diving seals from clotting, we instrumented two female grey seals (Halichoerus grypus) with subcutaneous electrodes for measurements of heart rate (HR) and an extradural intravertebral venous catheter for collection of blood samples before, during and after simulated dives of 10 min duration. Blood samples were used for in vitro determination of clot lysis time (CLT), which is a measure of the level of fibrinolytic activity, and for analyses of plasma levels of cortisol, noradrenaline and adrenaline (A). The seals displayed profound diving bradycardia indicative of a substantial reduction in blood flow rates (pre-dive HR: 78 (63-98) bpm; dive HR: 8 (7-10) bpm; (median (range); n = 2)) and elevated catecholamine levels (pre-dive A: 121 (98-184) pg.ml-1; peak dive/post-dive A: 3510 (447-6181) pg.ml-1), both of which are factors which promote blood coagulation. Nevertheless, we found that CLT always increased in connection with diving (pre-dive CLT: 436 (356-568) min; peak CLT during diving: 1380 (640-1800) min), which implies a reduced, rather than enhanced, fibrinolytic activity in this situation. These results show that enhanced fibrinolytic activity is not part of the defence system which prevents fatal clotting from occurring in diving grey seals.

Animals↗
PubMed1998

Urinary excretion of catecholamines in hospitalized and non-hospitalized healthy children and adolescents.

Non-conjugated catecholamines were measured in morning urine samples from 111 healthy, non-hospitalized subjects aged 8-18 y and in 16 hospitalized, healthy subjects aged 12 16 y. The catecholamines were extracted by cation exchange columns and alumina adsorption and quantitated with HPLC with electrochemical detection. The concentration of catecholamines was related both to the urinary creatinine concentration and to the collecting period and body surface area. Linear regression analysis was used to estimate continuous age-related reference centiles based upon the measurements from the 111 non-hospitalized subjects. The upper limits for the adrenaline/creatinine and noradrenaline/creatinine ratios were lower than in previous studies. The excretion of adrenaline and noradrenaline per hour and m2 body surface area was higher in the 16 hospitalized than in the 74 age-matched non-hospitalized subjects. The excretion of the catecholamines expressed per hour and m2 body surface area and expressed relative to creatinine excretion, decreased with increasing age, and the excretion of adrenaline and noradrenaline per hour and m2 body surface area was higher in boys than in girls. In conclusion, standardization of urine sampling leads to more narrow ranges for urinary adrenaline and noradrenaline excretion in healthy children and adolescents.

Adolescent↗
PubMed1998

Treatment with growth hormone and insulin-like growth factor-1 in septicemia: effects on carbohydrate metabolism.

Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) may be beneficial against the protein catabolism seen in injury and septicemia. Further understanding of their effects on carbohydrate metabolism is needed. In a septic porcine model receiving total parenteral nutrition, pretreatment with GH or IGF-1 (or no treatment in controls) was followed by an infusion of live Escherichia coli bacteria. Endogenous glucose production, carbohydrate oxidation, glucose and lactate fluxes over the liver, gastrointestinal organs, kidney, and hindleg were determined. Endogenous glucose production increased during septicemia in the GH group. The metabolic acidosis induced by septicemia was augmented by GH, but attenuated by IGF-1. The alanine and lactate levels were significantly higher in the GH- than in the IGF-1 treated animals during septicemia. IGF-1 pretreatment appeared to induce favorable effects while GH pretreatment might produce unfavorable effects on carbohydrate metabolism in septic piglets.

Alanine↗
PubMed1998

Effects of exercise on hypoglycaemic responses in insulin-dependent diabetes mellitus.

This study sought to determine whether moderate exercise influences hypoglycaemic responses in insulin-dependent diabetes mellitus (IDDM). Ten patients with IDDM and no history of hypoglycaemia unawareness or autonomic neuropathy were included. The patients were studied in random order on 4 occasions: twice during euglycaemia (once at rest and once on a treadmill) and twice during a gradual drop in blood glucose from 5 to 2 mmol/l (once at rest and once on a treadmill). Blood samples for hormones and glucose were drawn, and a symptom questionnaire was filled out every 5 min. Cognitive tests were performed at the start and end of each study. Glucose thresholds for hormones and symptoms are reported as the plasma glucose level at which responses were more than two standard deviations above basal level and continued to increase. The thresholds for adrenaline and noradrenaline release came at a significantly higher blood glucose level during exercise than at rest: 2.7 +/- 0.2 vs 2.1 +/- 0.2 mmol/l (p < 0.05) for adrenaline and 2.7 +/- 0.2 vs 2.0 +/- 0.1 mmol/l (p < 0.01) for noradrenaline. Thresholds for neuroglycopenic symptoms were also at a significantly higher blood glucose level during exercise: 2.6 +/- 0.2 vs 2.0 +/- 0.2 mmol/l (p < 0.05). During hypoglycaemia, patients showed a non-significant trend towards a lower score on cognitive tests during exercise than at rest. It is concluded that moderate exercise during a gradual drop in blood glucose does not mask hypoglycaemic responses in patients with IDDM.

Adult↗