Carnitine disposition before and during valproate therapy in patients with epilepsy

Free and total carnitine and acylcarnitine in plasma and urine samples was measured in 22 epileptic patients before and after 15 and 45 days of valproate (VPA) therapy and in 16 healthy volunteers on a single occasion. Carnitine plasma concentration and renal excretion observed in epileptic patients before VPA therapy did not differ from control values. After VPA was started, free and total plasma concentration decreased significantly (p < 0.05) from 49 +/- 17 to 35 +/- 16 at 15 days and to 35 +/- 13 nmol/ml at 45 days of therapy (free carnitine) and from 60 +/- 18 to 50 +/- 18 at 15 days and to 55 +/- 14 nmol/ml at 45 days of therapy (total carnitine), whereas acylcarnitine increased significantly (p < 0.05) from 10 +/- 8 to 14 +/- 8 at 15 days and to 18 +/- 16 nmol/ml at 45 days of therapy. Free carnitine urinary excretion decreased significantly (p < 0.05) from 200 +/- 135 to 115 +/- 76 and 118 +/- 75 mumol/24 h, whereas acylcarnitine urinary excretion increased significantly (p < 0.05) from 78 +/- 56 to 154 +/- 98 and 155 +/- 89 mumol/24 h after VPA therapy was started. As a consequence, acylcarnitine renal clearance increased significantly (+30%, p < 0.05) whereas free carnitine renal clearance did not change during VPA therapy. No difference was detected between 15 and 45 days of therapy. No patients experienced symptoms of VPA toxicity. Our results suggest that VPA in patients increases both formation and renal clearance of acylcarnitine.     

Cerebrospinal fluid cytology in patients with cancer: minimizing false-negative results

To investigate the contribution of dietary carbohydrate to glutamate and acetyl CoA synthesis, two groups of adult mice were fed a high- (HCD) or a low-carbohydrate diet (LCD) in which 5% of the carbohydrate was [U-13C]-glucose. Four animals from each dietary group were killed after 1, 2 and 5 d. The tracer:tracee ratios of [13C3] and [13C6]blood glucose and of the [13C2] and [13C3] isotopomers of blood, mucosal, hepatic and muscle alanine and glutamate were used to calculate the fractional contribution of glucose to the 3-carbon, acetyl CoA and oxaloacetate pools of each tissue. In the HCD mice, glucose contributed 66, 33 and 31% of the acetyl CoA pool of muscle, liver and mucosa, respectively. The contribution of glucose to acetyl CoA was lowered by 33% (P < 0.05) and 55% (P < 0.01) in the liver and muscle of the LCD group, respectively, but was unaltered in the mucosa. Glucose made a minor contribution to glutamate synthesis via oxaloacetate in the liver (23%) and muscle (10%) of the HCD group. The fraction of hepatic and muscle glutamate synthesis derived from glucose was not affected by the diet. We conclude that glucose oxidation in liver and muscle parallels the contribution of carbohydrate to dietary energy and that glucose is not a major carbon precursor for muscle glutamate synthesis. Net glutamate synthesis in extraintestinal tissues is preserved when dietary carbohydrate is restricted.     

Effect of glucose supplement timing on protein metabolism after resistance training

We determined the effect of the timing of glucose supplementation on fractional muscle protein synthetic rate (FSR), urinary urea excretion, and whole body and myofibrillar protein degradation after resistance exercise. Eight healthy men performed unilateral knee extensor exercise (8 sets/approximately 10 repetitions/approximately 85% of 1 single maximal repetition). They received a carbohydrate (CHO) supplement (1 g/kg) or placebo (Pl) immediately (t = 0 h) and 1 h (t = +1 h) postexercise. FSR was determined for exercised (Ex) and control (Con) limbs by incremental L-[1-13C]leucine enrichment into the vastus lateralis over approximately 10 h postexercise. Insulin was greater (P < 0.01) at 0.5, 0.75, 1.25, 1.5, 1.75, and 2 h, and glucose was greater (P < 0.05) at 0.5 and 0.75 h for CHO compared with Pl condition. FSR was 36.1% greater in the CHO/Ex leg than in the CHO/Con leg (P = not significant) and 6.3% greater in the Pl/Ex leg than in the Pl/Con leg (P = not significant). 3-Methylhistidine excretion was lower in the CHO (110.43 +/- 3.62 mumol/g creatinine) than P1 condition (120.14 +/- 5.82, P < 0.05) as was urinary urea nitrogen (8.60 +/- 0.66 vs. 12.28 +/- 1.84 g/g creatinine, P < 0.05). This suggests that CHO supplementation (1 g/kg) immediately and 1 h after resistance exercise can decrease myofibrillar protein breakdown and urinary urea excretion, resulting in a more positive body protein balance.     

Impaired fatty acid oxidation in children on valproic acid and the effect of L-carnitine

Fatty acid oxidation was studied in 12 patients (aged 3 to 19 years) receiving valproic acid (VPA), predominantly as monotherapy, before and after 1 month of L-carnitine supplementation (50 mg/kg/day po) in order to determine whether L-carnitine plays a role in preventing the hepatotoxic effects of this drug. Five of these patients were also studied prior to VPA treatment. Only one patient taking VPA had an abnormally low plasma free carnitine. Acyl-/free carnitine ratios were elevated in five patients on VPA and normalized after L-carnitine supplementation. Mean plasma concentrations of free fatty acids, beta-OH-butyrate, and cumulative excretion of 13CO2 after administration of 1-13C-octanoic acid were not changed by VPA or L-carnitine treatment. Urinary dicarboxylic acids, acylglycines, and octanoylcarnitine were elevated during VPA therapy and unaltered by L-carnitine. These results suggest that, in patients at low risk for VPA-induced hepatotoxicity (patients aged > 2 years and taking VPA as monotherapy), VPA causes metabolic abnormalities resembling those found in inborn errors of mitochondrial beta-oxidation which are not corrected by L-carnitine.     

Carnitine supplementation accelerates normalization of food intake depressed during TPN

When total parenteral nutrition (TPN; containing glucose, fat, and amino acids; caloric ratio 50:30:20) providing 100% of the rat's daily caloric intake is given for 3-4 days, food intake rapidly decreases by approximately 85%. After stopping TPN, there is a lag period of 3-4 days before food intake returns to previous level, which appears to be related to fatty acid oxidation and fat deposition. Carnitine plays a key role in the oxidation of fatty acids, and was demonstrated to reduce fat deposition in rats receiving TPN, by increasing beta oxidation. We therefore investigated whether rats receiving TPN supplemented with carnitine may prevent either the decrease or speed up the resumption or normalization of food intake, after TPN is stopped. Fourteen adult Fischer-344 rats had a central venous catheter inserted. After 10 recovery days, controls (n = 7) were infused with TPN providing 100% of rat's daily caloric intake for 3 consecutive days, followed by 4 more days of normal saline. The carnitine group (n = 7) received the same solution, but which provided 100 mg/kg/day carnitine. Daily food intake was measured and data were analyzed using ANOVA and Student's t-test. Both parenteral solutions depressed food intake maximally by almost 90% by day 3. Carnitine accelerated the normalization of food intake by decreasing the lag period by 1 day. We conclude that the addition of carnitine enhanced the normalization of post-TPN food intake and argue that this may be on the basis of enhanced fatty acid oxidation, a substrate known to play a significant role in the anorexia induced by TPN.     

Carnitine measurements in liver, muscle tissue, and blood in normal subjects

We determined carnitine concentrations in blood and in liver and abdominal muscle biopsy specimens in 13 men and 16 women undergoing elective surgery (mostly gallbladder removal). The data suggest that the carnitine pools of plasma and erythrocytes are different. The erythrocytes show a higher acylcarnitine concentration than does plasma (P < 0.001). Several reference bases for values in tissues have been used--dry weight, noncollagen protein (NCP), and DNA--because these may be differently influenced by disease. In liver specimens, the quotient NCP (g)/DNA (g) was significantly higher in men, 54.4 +/- 6.3 (mean +/- SD), than in women, 47.7 +/- 7.0 (P < 0.01). Liver total carnitine content in relation to DNA was significantly higher in men than in women: 0.29 +/- 0.06 vs 0.22 +/- 0.08 mmol/g DNA (P < 0.01). Free carnitine content was significantly higher in men than in women independently of the reference base, e.g., 3.7 +/- 1.0 mumol/g NCP for men vs 2.9 +/- 1.0 for women (P < 0.05). No difference was found between the sexes in the abdominal muscle carnitine content, 20.6 +/- 6.7 mumol/g NCP for men vs 17.9 +/- 5.0 for women. Our study establishes control ranges, thereby providing an important basis for studies of patients with abnormal carnitine metabolism.     

Oxidation of acetate and octanoate and its relation to glucose metabolism in contracting porcine carotid artery

The oxidation of octanoate and acetate was measured in segments of porcine carotid arteries to ascertain whether the oxidation of exogenous fatty acid substrates (acetate and octanoate) is augmented during contraction induced by K(+)-depolarization. The oxidation of acetate increased from 7 +/- 1 to 14 +/- 2 nmol/min/g (P < 0.01) during sustained isometric contraction. Octanoate oxidation increased from 11 +/- 1 to 14 +/- 1 nmol/min/g (P < 0.05). The rate of oxidation of neither acetate nor octanoate was affected by the presence or absence of glucose either in resting or contracting arteries Acetate or octanoate oxidation could account for the majority of O2 consumption during contraction. Octanoate but not acetate inhibited glucose uptake and glycolysis in resting muscles. In contrast to augmented acetate and octanoate metabolism during contraction, there was a "down-regulation" of glucose metabolism in contracting muscles as evidenced by a decrease in the rate of glucose uptake, glycolysis and lactic acid production during sustained isometric contraction. Thus, contractile activation of vascular smooth muscle is associated with a shifting pattern of substrate utilization. Exogenous acetate or octanoate can serve as the primary oxidative substrate during sustained isometric contraction.     

Contribution of D-(-)-3-hydroxybutyrate to the energy expenditure of neonatal pigs

In vivo oxidation rate of arterially infused D-(-)-3-hydroxybutyrate (3HB) was measured in 1-2-d-old-piglets. Twelve piglets (1.4 kg) were randomly assigned to a 12 h continuous infusion of 3HB at 19.5, 37.8, 55.8 or 74.5 mumol/min along with -31 kBq/h of [3-14C]3HB. Piglets were housed in respiration chambers allowing collection of total expired CO2 over 20-min intervals for the 12 h infusion and 6 h washout. Oxidation of 3HB was calculated from the quantity and specific radioactivity of expired CO2 for 20-min collection periods at 6, 9 and 12 h for each piglet and collectively plotted against plasma 3HB concentration measured in blood drawn during those 20-min periods. A Lineweaver-Burk plot of these data yielded a Km of 0.62 +/- 0.07 mmol/L and Vmax of 0.74 +/- 0.02 mmol ATP equivalents/(min.kg 0.75) (parameter estimate +/- SD), which could account for 32% of the piglet mean total ATP turnover of 2.3 mmol/(min.kg 0.75). These data show that 3HB oxidation is a linear function of plasma concentration in the physiologic range measured in piglets (0.006 mmol/L to 0.1 mmol/L) and within this range would account for 0.3% to 4.5% of piglet energy requirement. Oxidation of 3HB can meet a maximum of 30 to 40% of piglet energy requirement at unphysiologically high 3HB concentrations (> 3 mmol/L).     

Opportunities for promoting palliative medicine in cancer research

OBJECTIVE: To study the effect of cisplatin on plasma concentrations and urinary excretion of carnitine in ten patients with different malignancies treated with chemotherapy. METHODS: Carnitine concentrations were determined using a radioenzymatic assay and other metabolites by routine methods of clinical chemistry. Renal clearances were calculated by dividing urinary excretions by the respective plasma concentrations. RESULTS: Before treatment, all patients had a normal plasma carnitine concentration. During treatment with cisplatin, the plasma total carnitine concentration increased by approximately 30% and normalized 7 days after stopping therapy. Urinary excretion of total carnitine increased by a factor of 10 during cisplatin administration and also normalized 7 days after cessation of chemotherapy. This increase was due to excretion of both free carnitine and acylcarnitine and averaged approximately 1 mmol carnitine per day. Similarly, urinary clearance of total carnitine was increased during therapy with cisplatin by a factor of approximately 8 and returned to normal 7 days after chemotherapy. In comparison, patients with similar malignancies treated with radiotherapy showed no significant increase in renal carnitine excretion. Similar to urinary excretion of carnitine, excretion of glucose and phosphate, two metabolites also reabsorbed by the proximal tubule of the nephron, was increased during therapy with cisplatin. There was a strong linear correlation between urinary excretion of free carnitine and acylcarnitines. CONCLUSIONS: Treatment with cisplatin is associated with a tenfold increase in renal carnitine excretion, most likely due to inhibition of carnitine reabsorption by the proximal tubule of the nephron. Well-nourished patients support this loss of carnitine even after repeated cycles of chemotherapy without developing hypocarnitinaemia. However, cachectic patients with decreased dietary carnitine uptake may develop carnitine deficiency when treated repeatedly with chemotherapies including cisplatin.     

Palmitoyl-CoA stimulates cellular uptake and plasma membrane binding of carnitine

Carnitine cellular uptake and plasma membrane binding was investigated in S49 lymphoma cells. Palmitoyl-CoA was found to increase membrane binding of carnitine from 506 +/- 48 to 8,690 +/- 235 pmol/mg membrane protein. Palmitate and CoA acted synergistically and increased carnitine binding to plasma membranes but could not replace palmitoyl-CoA. The effect of palmitoyl-CoA on membrane binding of carnitine was maximal at 10 microM and required the presence of ATP. Palmitoyl-CoA increased the cellular uptake rate of carnitine from 181 +/- 5 to 884 +/- 25 amol/cell and h-1. We conclude that palmitoyl-CoA is a major regulator of cellular uptake of carnitine and, based on quantitative estimations, that the carnitine carrier binds more than one carnitine molecule.     

Carnitine acetyltransferase is not a cytosolic enzyme in rat heart and therefore cannot function in the energy-linked regulation of cardiac fatty acid oxidation

The subcellular location of cardiac carnitine acetyltransferase (CAT) was investigated by measuring the release of carnitine acetyltransferase and of marker enzymes from isolated rat myocytes permeabilized with digitonin. Additionally, the carnitine acetyltransferase activity exposed to the cytosolic compartment was quantified. The results indicate that soluble acetyl transferase is not present in the cytosol, and that only 5% of the cellular carnitine acetyltransferase activity is positioned to catalyse the formation of cytosolic acetyl coenzyme A. This situation makes it unlikely that the energy-linked regulation of cardiac fatty acid oxidation proceeds by mechanisms which require the conversion of acetylcarnitine to acetyl coenzyme A in the cytosol.     

Enzymic flow injection determination of free L-carnitine in infant formulae

Infant formula samples were analysed to determine their free L-carnitine content by using flow injection (FI) with an incorporated immobilised carnitine acetyltransferase bioreactor. The methodology was based on the spectrophotometric determination through its reaction with carnitine acetyltransferase coupled with acetyl coenzyme A (acetyl-CoA) and dithiobenzoate. The merging zones technique was used to minimise acetyl CoA consumption. Linearity was observed over the concentration range 10-80 mg l-1 with L-carnitine as standard (r = 0.9998) and the rate of analysis was 50 h-1 infant formula samples. The enzymic FI method afforded a low RSD (2.2%). Comparisons were made with other methods of known accuracy. The enzymic reactors were stable for 3 months when used daily at the optimum pH.     

Chiroinositol deficiency and insulin resistance. I. Urinary excretion rate of chiroinositol is directly associated with insulin resistance in spontaneously diabetic rhesus monkeys

Previously, we demonstrated that nondiabetic insulin-resistant monkeys had reduced covalent insulin activation of muscle glycogen synthase (GS) compared to normal monkeys and that covalent insulin activation of adipose tissue GS was absent in these monkeys. Covalent insulin activation of muscle and adipose tissue GS in monkeys with impaired glucose tolerance and noninsulin-dependent diabetes (NIDDM) was also absent. As in humans, monkeys with NIDDM have a lower urinary excretion rate of chiroinositol (CI), a component of a putative mediator of insulin action, compared to normal monkeys. To determine whether the urinary excretion rate of CI was related to insulin resistance, which develops naturally in many obese rhesus monkeys, we examined the relationships between 24-h urinary CI excretion rate and 1) whole body insulin-mediated glucose disposal rates (M) and insulin-mediated changes in 2) the skeletal muscle GS activity ratio (sm delta GSAR), 3) the skeletal muscle glycogen phosphorylase activity ratio, and 4) the adipose tissue GS activity ratio (at delta GSAR) in 27 monkeys ranging from normal (n = 12) to insulin resistant (n = 8) to overtly diabetic (n = 7). The urinary CI excretion rate was significantly correlated with M (r = 0.47; P < 0.02), sm delta GSAR (r = 0.38; P < 0.05), skeletal muscle glycogen phosphorylase activity ratio (r = -0.49; P < 0.01), and at delta GSAR (r = 0.46; P < 0.02). The urinary CI excretion rate was also correlated with glucose tolerance (r = 0.39; P < 0.05). There was a wide range of urinary CI excretion rates (0.42-5.17 mumol/day) in monkeys with normal fasting plasma glucose concentrations. However, of the 7 diabetic monkeys, 6 had a urinary CI excretion rate below 2.0 mumol/day, and in the subgroup of 16 monkeys with a urinary CI excretion rate less than 2.0 mumol/day, the associations of urinary CI with M rate (r = 0.65; P < 0.005), glucose tolerance (r = 0.63; P < 0.01), and sm delta GSAR (r = 0.73; P < 0.001) increased in strength and significance. We propose that the urinary CI excretion rate may be 1) a biochemical indicator of both in vivo and in vitro insulin resistance and 2) a noninvasive diagnostic tool with potential for the identification of those individuals at risk for NIDDM and other related diseases with insulin resistance.     

Effects of infused sodium lactate on glucose and energy metabolism in healthy humans

To assess the effects of lactate on glucose metabolism, sodium lactate (20 mumol.kg-1.min-1) was infused into healthy subjects in basal conditions and during application of a hyperinsulinaemic (6 pmol.kg-1.min-1) euglycaemic clamp. Glucose rate of appearance (GRa) and disappearance (GRd) were measured from plasma dilution of infused U- 13C glucose, and glucose oxidation (G(ox)) from breath 13CO2 and plasma 13C glucose. In basal conditions, lactate infusion did not alter G(ox) (8.8 +/- 0.9 vs 9.2 +/- 1.1 mumol.kg-1.min-1), while GRa slightly decreased from 15.2 +/- 0.8 basal to 13.9 +/- 0.9 mumol.kg-1.min-1 after lactate (p < 0.05). During a hyperinsulinaemic clamp, hepatic glucose production was completely suppressed with or without lactate. Lactate decreased G(ox) from 17.1 +/- 0.4 to 13.4 +/- 1.2 mumol.kg-1.min-1 (p < 0.05), whereas GRd was unchanged (39.7 +/- 3.6 vs 45.6 +/- 2.6 mumol.kg-1.min-1. It is concluded that infusion of lactate in basal conditions does not increase GRa or interfere with peripheral glucose oxidation, and that during hyperinsulinaemia lactate decreases glucose oxidation but does not alter hepatic or peripheral insulin sensitivity.     

Preferential elimination of pivalate with supplemental carnitine via formation of pivaloylcarnitine in man

1. To evaluate the effectiveness of carnitine administration in aiding the elimination of pivalate liberated from pivampicillin, studies were undertaken on seven paediatric patients treated for 7 days with combined pivampicillin and molar excess of carnitine. 2. A 22-fold increase occurred in urinary carnitine ester excretion on the last day of treatment (2967 +/- 604 versus 134 +/- 50 mumol/day, p < 0.05); the pivaloylcarnitine was identified with 13C-n.m.r. Only pivalate was detected in the urinary carnitine ester g.l.c. profile, the amount of this ester was equal to 92% of the daily pivalate intake. 3. The renal clearance rate of carnitine esters significantly exceeded that of creatinine indicating that the carnitine ester was eliminated by active transport. 4. The plasma concentration and urinary output of free carnitine were not changed significantly by the treatment, and the free and esterified carnitine concentrations in red cells remained unchanged indicating that carnitine deficiency was prevented.     

Successful treatment by direct hemoperfusion of coma possibly resulting from mitochondrial dysfunction in acute valproate intoxication

PURPOSE: We evaluated the efficacy of direct hemoperfusion (DHP) for treatment of acute valproate (VPA) intoxication and speculate on the biochemical perturbations that suggest a mechanism of coma induced by VPA overdose. PATIENT AND METHODS: The comatose patient was hospitalized approximately 6 h after ingesting 18 g VPA. DHP, with 200 g activated charcoal, was performed for 6 h. The plasma concentrations of VPA and Glasgow coma scale scores after admission were estimated. Before and after DHP, urine samples were tested in serial fashion for VPA metabolites, organic acids, and acyl carnitine esters of fatty acids. RESULTS: Plasma VPA was efficiently adsorbed on activated charcoal. The patient's plasma concentration of VPA decreased from 471 microg/ml (2,830 microM) to 45 microg/ml (270 microM), at which point the patient became alert. The half-life (t1/2) of VPA was calculated as 4.4 h before DHP and as 1.8 h during DHP. Before DHP, lactate and VPA-glucuronide markedly increased in urine samples, but beta-keto-VPA, a major mitochondrial metabolite, was not detected. Urinary excretion of carnitine esters of medium chain (C8-C10) dicarboxylic acids was increased. After DHP, lactate and VPA-glucuronide decreased, but a significant amount of beta-keto-VPA was demonstrated. Carnitine esters of medium chain dicarboxylic acids were decreased. CONCLUSIONS: DHP with activated charcoal was effective treatment for the patient with acute VPA intoxication and coma. The onset of coma may have been related to inhibition of beta-oxidation in the mitochondria, which was reversible by elimination of plasma VPA by DHP.     

Carnitine contents in remnant liver, kidney, and skeletal muscle after partial hepatectomy in rats: randomized trial

Carnitine, an important carrier of free fatty acid that is transported into mitochondria for beta-oxidation, was thought to be one of the key factors in the regulation of liver regeneration. If the carnitine content is insufficient in the hepatocyte, it might impair the energy substrate's transport and the energy charge required for cell regeneration. The purpose of this study is to evaluate the changes of carnitine content in remnant liver, kidney, and skeletal muscle simultaneously after partial hepatectomy in rats. Partial hepatectomy with resection of the median and left lateral lobes was performed on male Wistar rats. Rats with a sham operation comprised a control group. This study was an experimental randomized trial. Ten rats from each group were sacrificed before the operation and at 6, 24, 48, and 72 hours after the operation. The carnitine content, as total and free forms, in remnant liver, kidney, and skeletal muscle were quantified by high-performance liquid chromatography. The carnitine contents in the remnant liver increased significantly at 6, 24, and 48 hours after partial hepatectomy (p < 0.01). The increase of total carnitine content was more obvious than that of the free form. In contrast, the decreasing concentrations of total carnitine and free carnitine in the kidney were significant (p < 0.01). In skeletal muscle the total carnitine content decreased to a small extent, and it was observed only at 6 hours after partial hepatectomy (p < 0.05). It is suggested that remnant liver promoted the generation of carnitine, whereas kidney and skeletal muscle released their stored carnitine at an early stage after partial hepatectomy. As a result, the influx of the carnitine into hepatocytes increased at the regenerative stage. The carnitine content of remnant liver is sufficient during the early posthepatectomy stage.     

Effects of hyperinsulinemia under the euglycemic condition on calcium and phosphate metabolism in non-obese normotensive subjects

The effect of acute insulin infusion on the metabolism of calcium (Ca) and phosphate (P) was examined in 17 healthy subjects. They were hospitalized and kept on a constant diet for 5 days, and an euglycemic hyperinsulinemic glucose clamp was applied. Synthetic human insulin was infused at the rate of 40 mU/m2/min for 2 hr, and glucose was also infused to maintain basal glucose levels of each subject. The control study was performed in 8 of the 17 subjects, into whom 10% xylitol was infused for 2 hr at the rate of 100 ml/hr. The plasma insulin concentrations were 7.94 +/- 0.35 and 62.3 +/- 14.3 mU/liter before and after the glucose clamp technique, but serum free Ca ion was increased significantly (p < 0.05), and serum P and serum parathyroid hormone (PTH) were decreased significantly (p < 0.001). Creatinine clearance did not change during the glucose clamp technique. Urinary excretion of Ca (UCaV) was significantly higher after the glucose clamp than the control study. Fractional excretion of Ca (FECa) was increased significantly (p < 0.05), and urinary excretion of P (UPV) and fractional excretion of P (FEP) were decreased significantly (p < 0.05) under the hyperinsulinemic condition. The results suggested that, under the conditions of euglycemic hyperinsulinemia by glucose clamp technique, insulin increased the serum free Ca ion, and as a result, PTH was suppressed. Decreased PTH might induce calciuresis and enhance tubular P reabsorption under hyperinsulinemia. Insulin increased serum free Ca ion might relate to the vasodilating action of insulin by its decrease of intracellular free Ca ion in vascular smooth muscle.     

Integrated nutritional, hormonal, and metabolic effects of recombinant human growth hormone (rhGH) supplementation in trauma patients

An anabolic stimulus is needed in addition to conventional nutritional support in the catabolic "flow" phase of severe trauma. One promising therapy appears to be rhGH infusion which has direct as well as hormonal mediated substrate effects. We investigated on a whole-body level, the basic metabolic effects of trauma within 48-60 h after injury in 20 severely injured (injury severity score [ISS] = 31 +/- 2), highly catabolic (N loss = 19 +/- 2 g/d), hypermetabolic (resting energy expenditure [REE] = 141 +/- 5% basal energy expenditure [BEE]), adult (age 46 +/- 5 y) multiple-trauma victims, before starting nutrition therapy and its modification after 1 wk of rhGH supplementation with TPN (1.1 x REE calories, 250 mg N.kg-1.d-1). Group H (n = 10) randomly received at 8:00 a.m. on a daily basis rhGH (0.15 mg.kg-1.d-1) and Group C (n = 10) received the vehicle of infusion. Protein metabolism (turnover, synthesis and breakdown rates, and N balance); glucose kinetics (production, oxidation, and recycling); lipid metabolism, (lipolysis and fat oxidation rates), daily metabolic and fuel substrate oxidation rate (indirect calorimetry); and plasma levels of hormones, substrates, and amino acids were quantified. In group H compared to group C: N balance is less negative (-41 +/- 18 vs -121 +/- 19 mg N.kg-1.d-1, P = 0.001); whole body protein synthesis rate is 28 +/- 2% (P = 0.05) higher; protein synthesis efficiency is higher (62 +/- 2% vs 48 +/- 3%, P = 0.010); plasma glucose level is significantly elevated (256 +/- 25 vs 202 +/- 17 mg/dL, P = 0.05) without affecting hepatic glucose output (1.51 +/- 0.20 vs 1.56 +/- 0.6 mg N.kg-1.min-1), glucose oxidation and recycling rates; significantly enhanced rate of lipolysis (P = 0.006) and free fatty acid reesterification (P = 0.05); significantly elevated plasma levels of anabolic GH, IGF-1, IGFBP-3, and insulin; trauma induced counter-regulatory hormone (cortisol, glucagon, catecholamines) levels are not altered; trauma induced hypoaminoacidemia is normalized (P < 0.05) and 3-methylhistidine excretion is significantly low (P < 0.001). Improved plasma IGF-1 levels in Group H compared with Group C account for protein anabolic effects of adjuvant rhGH and may be helpful in promoting tissue repair and early recovery. Skeletal muscle protein is spared by rhGH resulting in the stimulation of visceral protein breakdown. The hyperglycemic, hyperinsulinemia observed during rhGH supplementation may be due to defective nonoxidative glucose disposal, as well as inhibition of glucose transport activity into tissue cells. The simultaneous operation of increased lipolytic and reesterification processes may allow the adipocyte to respond rapidly to changes in peripheral metabolic fuel requirements during injury. This integral approach helps us to better understand the mechanism of the metabolic effects of rhGH.     

Locations and molecular forms of gastrin-releasing peptide-like immunoreactive entities in ovine pregnancy

The effects of vasoconstrictors on bile flow and bile acid excretion were examined in single-pass isolated perfused rat livers. Administration of norepinephrine (NE), 4 nmol/min, plus continuous infusion of taurocholate (TC) (1.0 mumol/min) rapidly increased bile flow in 1 min, and from min 5 until the end of NE administration (late period) bile flow remained above the basal level (111.7 +/- 2.2%), as did bile acid output (114.6 +/- 1.8%). Without TC infusion, administration of NE produced no increase in the late period. Administration of NE plus taurochenodeoxycholate (1.0 mumol/min) increased bile flow and bile acid output in the late period to 121.9 +/- 7.0 and 137.1 +/- 6.8%, respectively. With NE plus taurodehydrocholate, the respective values were only 105.4 +/- 1.6 and 104.1 +/- 4.0%. When horseradish peroxidase (HRP) (25 mg) was infused over 1 min with continuous NE, the late peak (20-25 min) of HRP elimination into bile significantly exceeded that of untreated controls (P < 0.01). These observations suggest that vasoconstrictors enhance biliary excretion of more hydrophobic bile acids, in part by stimulating vesicular transport.