Plasma Galanin Research Articles

Maternal neuropeptide galanin levels in pregnancies with intra-uterine growth restriction (IUGR): neurohormonal regulation of fetal weight.

Galanin is a neuroendocrine peptide with diverse biological actions in humans. Here, we evaluated plasma galanin levels in pregnant women with intrauterine growth restriction (IUGR) to elucidate the mechanism underlying the causal link between regulatory neuropeptides and IUGR. This prospective case-control study evaluated 40 IUGR pregnancies and 35 healthy body mass index (BMI) and age-matched second and third-trimester pregnant women at Istanbul Teaching and Research Hospital. Serums galanin levels were determined using an enzyme-linked immunosorbent assay (ELISA) kit according to the manufacturer's procedure. Median serum galanin levels were lower in the IUGR group (9.59pg/ml) than in the control group (12.1pg/ml), although statically insignificant. Galanin levels were significantly higher in the control group with a BMI ≥ 30 than in those with a BMI < 30; the IUGR group exhibited no significant difference. Galanin levels were higher in the control group premature births than in term pregnancies; the difference was insignificant in the IUGR group. Thus, IUGR minimally impacts circulating maternal galanin levels, indicating that while galanin might affect IUGR pathogenesis, it negligibly contributes to disease progression. The lack of correlation between galanin levels and maternal BMI and preterm pregnancies suggests a blunted neuropeptide response to hormonal stimulus in IUGR pregnancies, compared with the positive association with maternal BMI and negative association with healthy preterm pregnancies.

The Role of Galanin, Alarin, Irisin, PGC1-Α and BDNF in the Pathophysiology of Alzheimer's disease

The roles of novel peptides such as peroxisome proliferator-activated receptor gamma coactivator 1- alpha (PGC1-α), irisin, brain-derived neurotrophic factor (BDNF), galanin and alarin in Alzheimer's disease (AD) are not fully known. It was aimed to plasma levels of the novel peptides that may affect the pathophysiology of AD were examined. This study was conducted as a cross-sectional. The study consisted of two groups, including 45 newly diagnosed individuals with AD and 45 healthy individuals. The peptide levels in plasma samples collected from the groups were measured by the ELISA method. The mean plasma peptide levels and age differences, between the groups, and the correlations between them were analyzed by the statistically. The means ages of both groups were over 65 years old. When plasma PGC1-α, irisin, BDNF, galanin, and alarin levels between the groups were examined, decreases were found in the group with AD (3.56±0.79ng/mL, 16.33±4.07ng/mL, 3.36±1.47ng/mL, 13.93±4.24ng/L, 31.99±11.89pg/mL, respectively) compared to the control group (4.23±1.31ng/mL, 22.19±9.61ng/mL, 4.58±2.10ng/mL, 14.4±9.01ng/L, 54.93±15.80pg/mL, respectively). In the negative correlations observed between age and plasma peptide levels. Significant positive correlations were observed between plasma PGC1-α levels and irisin, alarin, and BDNF, and the significant positive correlations were also observed between plasma BDNF levels and irisin and alarin. As far as we know, the study is the first report in which the peptides mentioned in AD were examined together. We consider that more detailed studies are needed to shed light on the roles and mechanisms of these peptides in AD.

Galanin expression is down-regulated in patients with gastric cancer.

ObjectiveTo investigate whether galanin and its three receptors (Gal-R1, Gal-R2, Gal-R3) contribute to development of gastric cancer.MethodsPreoperative and postoperative fasting venous blood samples were collected from 34 patients with gastric cancer and 13 healthy individuals. Plasma galanin contents, as well as expression levels of galanin and its receptors, were quantitatively examined in a cohort of human gastric cancer tissues and corresponding adjacent tissues.ResultsStatistically significantly lower galanin levels were found in the preoperative samples from patients with gastric cancer, compared with postoperative samples from these same patients, as well as with samples from healthy donors. Furthermore, galanin and Gal-R1 expression levels were dramatically reduced in gastric cancer tissues, compared with corresponding adjacent tissues, whereas Gal-R2 and Gal-R3 levels remained unchanged. Furthermore, galanin mRNA and protein expression levels in the preoperative samples from patients with gastric cancer were significantly correlated with lymph node metastasis, tumor node metastasis stage, and size of the gastric cancer.ConclusionsOverall levels of galanin and Gal-R1 expression were down-regulated in patients with gastric cancer; local levels were also specifically downregulated in gastric cancer tissues. Galanin and its receptor, Gal-R1, may contribute to development of gastric cancer.

Validation of antibody-based tools for galanin research

Antibodies are an integral biomedical tool, not only for research but also as therapeutic agents. However, progress can only be made with sensitive and specific antibodies. The regulatory (neuro)peptide galanin and its three endogenous receptors (GAL1-3-R) are widely distributed in the central and peripheral nervous systems, and in peripheral non-neuronal tissues. The galanin system has multiple biological functions, including feeding behavior, pain processing, nerve regeneration and inflammation, to name only a few. Galanin could serve as biomarker in these processes, and therefore its receptors are potential drug targets for various diseases. For that reason, it is of paramount interest to precisely measure galanin peptide levels in tissues and to determine the cellular and subcellular localization of galanin receptors. A plethora of antibodies and antibody-based tools, including radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) kits, are commercially available to detect galanin and its receptors. However, many of them lack rigorous validation which casts doubt on their specificity. A goal of the present study was to raise awareness of the importance of validation of antibodies and antibody-based tools, with a specific focus on the galanin system. To that end, we tested and report here about commercially available antibodies against galanin and galanin receptors that appear specific to us. Furthermore, we investigated the validity of commercially available galanin ELISA kits. As the tested ELISAs failed to meet the validation requirements, we developed and validated a specific sandwich ELISA which can be used to detect full-length galanin in human plasma.

Correlation between plasma galanin and 5-hydroxytryptamine and psychological status in patients with gastroesophageal reflux disease

目的：探讨甘丙肽（galanin,GAL）及5-羟色胺（5-hydroxytryptamine,5-HT）在不同亚型的胃食管反流病（gastroesophageal reflux disease,GERD）患者血浆中表达水平的差异及其与焦虑、抑郁的关系.方法：采用焦虑自评量表（Self-rating Anxiety Scale,SAS）和抑郁自评量表（Self-rating Depression Scale,SDS）对GERD患者和健康对照组进行测试,评定心理状况;采用酶联免疫吸附法（enzyme linked immunosorbent assay,ELISA）分析GERD患者和健康对照组血浆中5-HT、GAL的含量.结果：无合并焦虑、抑郁的GERD患者与健康对照组比较,5-HT升高,GAL下降（t=1.97,P〈0.05）;非糜烂性反流病（non-erosive reflux disease,NERD）患者与反流性食管炎（reflux esophagitis,RE）患者比较,焦虑、抑郁问题更严重（F分别为55.92、36.51,均P〈0.05）,且与健康对照组相比,5-HT下降,GAL升高（F分别为54.53、8.00,均P〈0.05）;5-HT与SAS、SDS评分呈负相关（r分别为-0.789、-0.787、均P〈0.05）,GAL与SAS、SDS评分呈正相关（r分别为0.688、0.705,均P〈0.05）,5-HT与GAL呈负相关（r=-0.744,P〈0.05）.结论：无合并焦虑、抑郁的GERD患者,5-HT升高,GAL下降;NERD患者比RE患者焦虑、抑郁问题更严重,5-HT下降,GAL升高;焦虑、抑郁问题越严重,5-HT越低,GAL越高.

Association between circulating levels of galanin and pre-pregnancy body mass index in patients with gestational diabetes mellitus

Galanin is an important neuropeptide which induces an increase in obesity and appetite, improving insulin sensitivity and glucose tolerance in experimental animals. Although significantly higher levels of plasma galanin are found in pregnant women with gestational diabetes mellitus (GDM), there is a limited understanding of its precise mechanism underlying this variation. In the present study, concentrations of circulating galanin were determined at baseline in pregnant women with GDM and pregnant women with normal glucose tolerance (NGT). Correlation analyses were performed between galanin and pre-gestational body weight, pre-gestational BMI, and hormone involved in various homeostatic processes. Results showed that plasma galanin level was significantly higher in the patients with GDM than in the NGT subjects (p<0.001). Plasma galanin was positively correlated with pre-gestational body weight (r=0.42, p=0.037), pre-gestational BMI (r=0.643, p=0.001), and fasting blood glucose (r=0.840, p<0.001) in the GDM group. Moreover, a significant negative correlation was shown between galanin and sex hormone binding globulin (SHBG) (r=−0.901, p<0.001) in the GDM group. These data indicate that serum galanin concentration increases markedly in pregnant women with GDM, and this increase seems to be related to the increase of pre-gestational BMI and significantly lower SHBG in patients with GDM. Thus, circulating galanin is affected under conditions of altered pre-gestational BMI with highest levels in GDM patients. The increase of galanin under conditions of GDM may indicate a physiological function to improve glucose tolerance which is often impaired in GDM subjects.

Influence of bed rest on plasma galanin and adrenomedullin at presyncope.

The role of hormones in reduced orthostatic tolerance following long-term immobilization remains uncertain. We have previously shown that plasma concentrations of adrenomedullin and galanin, two peptides with vasodepressor properties, rise significantly during orthostatic challenge. We tested the hypothesis that bedrest immobilization increases the rise in adrenomedullin and galanin during orthostatic challenge leading to presyncope. We measured baseline (supine), presyncope and recovery (10min postpresyncope, supine) levels of adrenomedullin and galanin in 8 healthy men, before and after 21days of -6° head-down bed rest (HDBR). Presyncope was elicited using a combined head-up tilt and graded lower body negative pressure protocol. Orthostatic tolerance was defined as the time taken from the commencement of head-up tilt to the development of presyncope. Orthostatic tolerance time after HDBR reduced by 8·36±5·39min (P=0·0032). HDBR increased plasma adrenomedullin concentration to orthostatic challenge (P=0·0367). Compared to pre-HDBR, a significant rise in post-HDBR presyncopal (P<0·001) and recovery adrenomedullin concentration (P<0·01) was demonstrated. In contrast, we observed no change in pre- and post-HDBR galanin levels to orthostatic challenge. Bedrest immobilization appears to affect adrenomedullin levels in that greater increases in adrenomedullin occur at presyncope following bedrest immobilization. Due to its peripheral vasculature hypotensive effect, the greater levels of adrenomedullin at presyncope following bedrest immobilization may have contributed to the reduced orthostatic capacity postbedrest.

The Effects of Levetiracetam on Cerebrospinal Fluid and Plasma NPY and GAL, and on the Components of Stress Response System, hs-CRP, and S100B Protein in Serum of Patients with Refractory Epilepsy

Our objective is to explore the effects of levetiracetam on the levels of neuropeptides, serum activity and concentrations of oxidative stress and inflammatory response proteins, and levels of brain injury marker in patients with refractory epilepsy. Seventy-two patients with refractory epilepsy received levetiracetam treatment. Neuropeptides galanin (GAL) and neuropeptide Y (NPY) in plasma and cerebrospinal fluid (CSF) were detected using double-antibody sandwich immunoassay and radioimmunoassay, respectively. Enzyme-linked immunosorbent assay was used to detect serum activity of paraoxonase (PON1) and serum concentrations of oxidized low-density lipoprotein (ox-LDL) and S100B. Arylesterase (ARE) activity was measured by colorimetric assay, and immune scatter turbidimetry was used to detect a high-sensitivity C-reactive protein (hs-CRP). After treatment, NPY and GAL in plasma and CSF of the patients were significantly decreased as compared to concentrations before treatment (P<0.05). Levetiracetam reduced serum activities of PON1 and ARE (P<0.05) and led to markedly increased serum levels of ox-LDL (P<0.05). Serum concentrations of hs-CRP and S100B protein were significantly lower after levetiracetam administrations than before treatment (P<0.05). Levetiracetam treatment had a clear beneficial effect on the overall quality of life (QOL) scores of the patients, as indicated by significantly improved cognitive functioning, behavior problems, emotional conditioning, physical condition, social functioning, self-assessed life quality score, self-assessed health score, and the total QOL score (P<0.05). Levetiracetam can improve life quality of patients with refractory epilepsy, decrease NPY and GAL in plasma and cerebrospinal fluid, serum PON1 and ARE activities, and serum levels of ox-LDL, hs-CRP, and S100B. Levetiracetam therefore may be considered a drug of choice for treating refractory epilepsy.

Plasma galanin is a biomarker for severity of major depressive disorder.

This study investigated the association between plasma galanin level and depression severity. The severity of depression symptoms of 79 patients with major depressive disorder (MDD; 52 women and 27 men, 71 patients in onset, 8 in remission) was assessed using the 17-item Hamilton Depression Rating Scale. Venous fasting blood samples (5 mL) were taken from the 79 MDD patients, 35 healthy siblings, and 19 healthy controls, and plasma samples were prepared. Galanin levels in the plasma were measured by radioimmunoassay. Plasma galanin in MDD patients was significantly higher than that of remission patients, healthy siblings, or healthy controls (P < 0.05) There was no significant difference between the healthy sibling and healthy control groups (P = 0.924). Plasma galanin of remission patients was also significantly higher than that of healthy controls (P < 0.05). There was no significant correlation between age and galanin levels in the 79 patients (r = 0.053, P = 0.646), nor was there a correlation between age and galanin levels when patients were stratified by gender (P > 0.05). There was a significant positive correlation between plasma galanin levels and depression severity in women MDD patients (r = 0.329, df = 42, P = 0.020), but not in men patients. Plasma galanin levels may be an important biomarker for depression severity, especially in female patients.

Endogenous galanin as a novel biomarker to predict gestational diabetes mellitus

Although a significantly higher level of plasma galanin was found in patients with gestational diabetes mellitus (GDM) in our previous study, it is unknown whether plasma galanin is biomarker for the prediction of GDM. The present study aims to further evaluate the relationship between endogenous galanin and GDM in pregnant women and to find out the precise mechanism by which galanin plays role in the pathogenesis of GDM. The study registered thirty pregnant women with GDM and thirty pregnant women with normal glucose tolerance (NGT). Demographic and biochemical parameters and fasting venous blood samples of two groups were collected from all cases. Galanin was analyzed by an enzyme-linked immunosorbent assay. Gamma-glutamyl transferase (GGT) was measured by enzymatic methods. The plasma galanin and GGT levels were found higher in GDM compared with NGT (P<0.001). In addition, a significant positive correlation was shown between galanin and fasting glucose (P=0.049), 1-h glucose (P=0.033), body mass index (BMI) (P<0.001) and GGT (P=0.048) in pregnant women with GDM, whereas there was significant positive correlation between galanin and BMI (P=0.030) in NGT group. The plasma galanin and GGT levels are higher in patients with GDM. The plasma galanin levels appear to be related to the changes of blood glucose, BMI and GTT in GDM. The higher level of galanin observed in GDM may represent a adaptation to the rise of glucose, weight, GGT associated with GDM. The higher level of plasma galanin is a novel biomarker for the prediction of GDM.

Circulating galanin levels are increased in patients with gestational diabetes mellitus

BackgroundGalanin is a 29/30-amino acid peptide that stimulates food intake and regulates energy metabolism. A significantly higher level of plasma galanin was found in diabetes in non-pregnant women, but there are no data regarding galanin levels in diabetes in pregnant women. In this study we compared plasma galanin concentrations in pregnant women with gestational diabetes mellitus (GDM) and normal glucose tolerance (NGT). Material and methodsThe study registered twenty pregnant women with GDM and twenty pregnant women with NGT. Fasting venous blood samples were collected from all cases. Galanin was analyzed by an enzyme-linked immunosorbent assay. ResultsA statistically significant higher level of galanin was found in pregnant women with GDM compared with NGT (P<0.001). In addition, a significant positive correlation was shown between galanin and glucose (P<0.001), galanin and BMI (P=0.008) in pregnant women with GDM, although there was no association between galanin and insulin and/or galanin and HbA1c. ConclusionsCirculating galanin levels are higher in patients with GDM. Circulating galanin levels appear to be related to the changes of blood glucose in GDM. The higher level of galanin observed in GDM may represent a physiological adaptation to the rise of glucose associated with GDM.

Effect of Gestational Diabetes and Intrauterine Growth Restriction on the Offspring's Circulating Galanin at Birth

Experimental studies linked gestational diabetes mellitus (GDM) and intrauterine growth restriction (IUGR) with altered expression of the offspring's hypothalamic galanin mRNA, possibly contributing to the development of obesity and metabolic syndrome in later life. We hypothesized that plasma galanin levels at birth would reflect presumably altered hypothalamic galanin expression and production that cannot be assessed in the human offspring. Our objective was to investigate whether neonates born to GDM mothers or being IUGR differ from healthy ones in circulating galanin at birth. Twenty-five neonates born to GDM mothers, 25 with IUGR, and 15 healthy neonates (controls) were prospectively studied. Neonatal plasma galanin levels were assayed immediately after birth by using enzyme immunoassay. Neonatal plasma galanin showed a high variability within each group and did not differ significantly among the three groups of neonates. No correlation between plasma galanin and anthropometric maternal and neonatal data was found. Multiple linear regression confirmed that the neonatal group (infants of diabetic mothers, IUGR, and controls) was not an independent predictor for galanin levels at birth after controlling for possible confounders, i.e. maternal body mass index and weight gain during pregnancy and neonatal body mass index. Circulating galanin levels at birth are not affected by GDM and IUGR, providing no evidence for alternations in hypothalamic galanin expression and secretion in humans, as they were previously documented in experimental models. This fact precludes the use of plasma galanin as an early indicator for the development of obesity and metabolic syndrome in this high-risk population.

Exercise-induced galanin release facilitated GLUT4 translocation in adipocytes of type 2 diabetic rats

Although galanin has been shown to increase insulin sensitivity in skeletal muscle of rats, there is no literature available about the effect of galanin on Glucose Transporter 4 (GLUT4) translocation from intracellular membrane pools to plasma membranes in adipocytes of type 2 diabetic rats. In the present study M35, a galanin antagonist was used to elucidate whether exercise-induced galanin release increased GLUT4 translocation in adipocytes of streptozotocin-induced diabetic rats. The present findings showed that plasma galanin levels after swimming training in all four trained groups were higher compared with each sedentary control. M35 treatment had an inhibitory effect on glucose infusion rates in the euglycemic–hyperinsulinemic clamp test and GLUT4 mRNA expression levels in adipocytes. Moreover, M35 treatment reduced GLUT4 concentration in both plasma membranes and total cell membranes. The ratios of GLUT4 contents in plasma membranes to total cell membranes in four drug groups were lower compared with each control. These data demonstrate a beneficial role of endogenous galanin to transfer GLUT4 from internal stores to plasma membranes in adipocytes of type 2 diabetic rats. Galanin plays a significant role in regulation of glucose metabolic homeostasis and is an important hormone relative to diabetes.

Galanin antagonist increases insulin resistance by reducing glucose transporter 4 effect in adipocytes of rats

Seeing that galanin increases animal body weight on the conditions of inhibiting insulin secretion and animals with metabolic disorder of galanin easily suffer from diabetes, we postulate that endogenous galanin is necessary to reduce insulin resistance in adipocytes. To test this hypothesis, we compared four groups of rats to examine whether an increase in galanin secretion stimulated by swimming may reduce insulin resistance. The rats from sedentary and trained drug groups were injected by M35, a galanin antagonist. The rats from trained control and trained drug groups swam after each injection for four weeks. We found that exercise significantly elevated plasma galanin contents and glucose transporter 4 (GLUT4) mRNA levels in adipocytes. Meanwhile, M35 treatment reduced GLUT4 and GLUT4 mRNA levels, and glucose infusing rates in euglycemic-hyperinsulinemic clamp tests. The ratios of GLUT4 concentrations at plasma membranes to total cell membranes in both drug groups were lower compared with each control group, respectively. These observations suggest that endogenous galanin reduces insulin resistance by increasing GLUT4 contents and promoting GLUT4 transportation from intracellular membranes to plasma membranes in adipocytes. Galanin is an important hormone to reduce insulin resistance in rats.

Beneficial effect of galanin on insulin sensitivity in muscle of type 2 diabetic rats

The aim of this study was to determine whether enhanced galanin (GAL) release induced by exercise would elevate insulin sensitivity and glucose transporter 4 (GLUT4) concentration in the plasma membranes of skeletal muscle in type 2 diabetic rats. We used M35, a GAL antagonist to antagonize the GAL function and swimming training for four weeks to increase GAL release of rats. The blood samples were analyzed for GAL and insulin concentration. The euglycemic-hyperinsulinemic clamp test was conducted for an index of glucose infusion rates. Additionally, skeletal muscle was collected and processed for GLUT4 mRNA level and GLUT4 concentration. The present findings showed that plasma GAL levels after swimming training in all three trained groups were higher compared with each sedentary control and each preswimming level. The insulin levels after swimming in both M35 treatment groups were elevated compared with each diabetic control and each pretraining level. Moreover, M35 treatment reduced glucose infusion rates compared with each diabetic control, but swimming enhanced the rates in all trained groups compared with each sedentary control. Furthermore, M35 treatment reduced GLUT4 concentration and GLUT4 mRNA levels compared with each diabetic control. The ratio of GLUT4 contents in plasma membranes to total cell membranes in both drug groups were lower compared with each diabetic control. These results suggest that endogenous GAL may enhance GLUT4 contents and promote GLUT4 transportation from intracellular membrane pools to plasma membranes. GAL is an important hormone to regulate insulin sensitivity in skeletal muscle from type 2 diabetic rats.

Effect of M35, a neuropeptide galanin antagonist on glucose uptake translated by glucose transporter 4 in trained rat skeletal muscle

In this study, we used M35, a galanin antagonist to explore the effect of an increase in galanin release induced by exercise on glucose transporter 4 (GLUT4) content and function. The rats tested were divided into four groups: rats from sedentary and trained drug groups were injected by M35, 5 times per week during four weeks. Rats from sedentary and trained control groups by 0.1 mol/l citrate buffer. The rats from both exercise groups swam after each injection. The results showed that M35 significantly decreased glucose infusing speeds in euglycemic–hyperinsulinemic clamp tests. M35 treatment elevated plasma insulin levels in both drug groups. And the insulin levels in both drug groups were higher also than that after experiments in each control group respectively. The four weeks swimming enhanced the plasma galanin contents. The galanin levels after experiments in both exercise groups were higher than that in each sedentary control group respectively too. The GLUT4 densities were attenuated by M35 at plasma membranes and total cell membranes. The change ratios of GLUT4 immunoreaction at plasma membranes to total cell membranes were lower in both drug groups compared to each control group. Those results suggest that endogenous galanin has an important attribute to elevate the insulin sensitivity by increasing GLUT4 contents and promoting GLUT4 transportation from intracellular membranes to plasma membranes in muscle cells. Galanin is an important hormone to elevate insulin sensitivity in rest and exercise conditions.

Plasma Galanin, Vasopressin, and Oxytocin in Patients with Addison's Disease

Galanin is colocalized with adrenocorticotrophin (ACTH) in the human pituitary and with corticotrophin releasing hormone, arginine, vasopressin, and oxytocin in the hypothalamus. Galanin, vasopressin, and oxytocin influence the secretion of pituitary ACTH. The aim of this study was to investigate if the endogenous stimulation of ACTH release in Addison's disease was reflected in plasma galanin, vasopressin, and oxytocin. ACTH, galanin, vasopressin, and oxytocin were measured in plasma from 14 patients with Addison's disease, one patient with Nelson's syndrome, and 14 healthy controls. Eight patients had elevated plasma ACTH whereas six patients and all controls had ACTH levels within the reference-range. There was no difference in galanin or vasopressin between patients and controls or between samples with low or high ACTH concentrations. In contrast, oxytocin was higher in patients with elevated plasma ACTH compared to patients and controls with normal or low ACTH. No relation was found between galanin or oxytocin and age or sex. A tendency towards lower vasopressin with increasing age was found among the men (p=0.057). The highest ACTH and galanin levels were found in the patient with Nelson's syndrome. In conclusion, increased plasma ACTH was not reflected in elevated plasma galanin or vasopressin. In contrast, elevated ACTH levels were accompanied by higher oxytocin levels.

Galanin concentrations in maternal circulation, amniotic fluid and umbilical cord blood during term labor: Relationship with maternal body mass and neonatal birth weight

Background. Galanin is a hypothalamic regulatory peptide involved in the regulation of appetite. It is synthesized by the nervous system, anterior pituitary gland, adrenal medulla, pancreas, intestine and placenta. Placental secretion of galanin has until now only been investigated in animals. Additionally, galanin concentration has not been assessed in umbilical cord blood and amniotic fluid.Patients and methods. Galanin concentrations were measured in maternal circulation before term delivery, in cord blood and in amniotic fluid of 45 healthy pregnant women (gestational age 38 – 40 gestational weeks). The control group consisted of 26 normally menstruating healthy women.Results. Plasma galanin concentrations were found to be similar in pregnant healthy women before term delivery (20.8 ± 1.9 pg/ml) and non-pregnant women (19.0 ± 1.7 pg/ml). Galanin concentration in umbilical cord blood (26.5 ± 2.2 pg/ml) was significantly higher (p < 0.05) than in maternal circulation. Galanin concentration in amniotic fluid (20.4 ± 1.0 pg/ml) was similar to that observed in maternal plasma, but significantly (p < 0.01) lower than in umbilical cord blood. A significant correlation was found between maternal body mass index and plasma galanin concentration (τ = 0.246; p < 0.05) and between birth weight and cord blood galanin concentration (τ = 0.345; p = 0.01). There was no significant correlation between placental mass and cord blood galanin concentration (τ = 0.124; p = 0.26).Conclusions. Plasma galanin concentration in pregnant women before term delivery is similar to that in non-pregnant women. The fetus rather than the placenta is the source of the high galanin concentration in umbilical cord blood. The role of galanin in the regulation of newborn weight is uncertain.

Circulatory galanin levels increase severalfold with intense orthostatic challenge in healthy humans

The purpose of this study was to test the hypothesis that plasma galanin concentration (pGal) is regularly increased in healthy humans with extensive orthostatic stress. Twenty-six test persons (14 men, 12 women) were brought to an orthostatic end point via a progressive cardiovascular stress (PCS) protocol consisting of 70 degrees head-up tilt plus increasing levels of lower body negative pressure until either hemodynamically defined presyncope or other signs of orthostatic intolerance occurred (nausea, clammy skin, excessive sweating, pallor of the skin). We further tested for possible gender, gravitational, and muscular training influences on plasma pGal responses: PCS was applied before and after 3 wk of daily vertical acceleration exposure training on a Human Powered Centrifuge. Test persons were randomly assigned to active (with bicycle work) or passive (without work) groups (seven men, six women in each group). Resting pGal was 26+/-3 pg/ml in men and 39+/-15 pg/ml in women (not significant); women had higher galanin responses (4.9-fold increase) than men (3.5-fold, P=0.017) to PCS exposure. Overall, PCS increased pGal to 186+/-5 pg/ml (P=0.0003), without significant differences between presyncope vs. orthostatic intolerance, pre- vs. postcentrifuge, or active vs. passive gravitational training. Increases in pGal were poorly related to synchronous elevations in plasma vasopressin. We conclude that galanin is regularly increased in healthy humans under conditions of presyncopal orthostatic stress, the response being independent of gravity training but larger in women than in men.

Heterogeneous Forms of Immunoreactive Galanin in Human Plasma; Higher Levels in Men than in Women

Galanin, a neuropeptide, has important effects on hormone secretion from the hypothalamus and pituitary, and may also be involved in important biological processes such as pain, memory, and food intake. Yet, there is limited knowledge about how these processes are reflected by circulating galanin. To study the levels and molecular forms of galanin in the human circulation, plasma was analysed from 27 healthy subjects, 14 women and 13 men, using two extraction methods and a specific radioimmunoassay for human galanin. After extraction on Sep Pak C-18 columns, plasma galanin-like immunoreactivity (galanin-LI) in the healthy men was 6.3 +/- 2.5 pmol/l (mean +/- SD, n = 12), which was higher than in the women, 4.1 +/- 1.5 pmol/l (n = 14, p = 0.010). A small increase in galanin-LI was seen with age in the women (r = 0.54, p < 0.05) but there was no significant difference between pre- and postmenopausal women. Galanin immunoreactivity after Sep Pak and immunoextraction correlated (r = 0.74, p < 0.001) the levels being higher after immunoextraction (p < 0.001). Gel chromatography disclosed heterogeneity of circulating galanin-LI with the majority eluting as homologs with a molecular weight higher than synthetic human galanin. Homologs smaller than galanin were also found. Sep Pak C-18 extraction eliminated the majority of the higher molecular forms. In conclusion, circulating galanin-LI was found to be higher in men and to be present mainly as molecular forms larger than synthetic galanin.