Increased plasma neurotensin concentrations in patients with Parkinson's disease.

Plasma neurotensin (NT) was measured by radioimmunoassay in propanol extracted and unextracted plasma from 16 parkinsonian patients (four before treatment) and 16 age and sex matched controls. Mean plasma NT concentrations were consistently higher in parkinsonian patients than in controls and higher in the four untreated patients than in levodopa treated patients suggesting that plasma NT measurement may represent an easy detectable additional index in diagnosing parkinsonism and provides a novel approach to research in this field.

Possible role of plasma neurotensin on growth hormone regulation in neonates.

OBJECTIVE: To evaluate secretion of plasma neurotensin (NT) which could be involved as a peripheral signal in growth hormone (GH) regulation, NT release was measured during early postnatal life, a period of striking changes in GH secretion. METHODS: Blood samples were collected from 19 normal full-term neonates on day 5 and at 3 months of age to evaluate plasma NT concentrations by radioimmunoassay, serum growth hormone (GH) levels using an immunofluorometric assay, and serum insulin-like growth factor-I (IGF-I) values by radioimmunoassay. RESULTS: Five day-old neonates showed significantly higher (p < 0.001) mean (+/- SEM) plasma NT levels (83.55 +/- 12.07 fmol/ml) compared with those in 11 prepubertal children and those in 14 adults who were studied as control subjects (13.30 +/- 2.90 and 9.70 +/- 1.10 fmol/ml, respectively). In 5 day-old neonates we observed significantly higher (p < 0.001) serum GH levels (29.53 +/- 3.40 ng/ml) compared with those in the prepubertal children (1.26 +/- 0.28 ng/ml). Five day-old neonates showed significantly lower (p < 0.001) serum IGF-I concentrations (27.01 +/- 0.77 ng/ml) than those in the prepubertal children (210 +/- 25 ng/ml). At 3 months of age, plasma NT levels (59.37 +/- 7.47 fmol/ml) and serum GH values (4.40 +/- 0.60 ng/ml) were significantly decreased (p < 0.001). At the 3rd month of life, serum IGF-I levels (44.88 +/- 4.30 ng/ml) were increased significantly (p < 0.001). CONCLUSIONS: The human neonate showed very high concentrations of NT and GH in comparison with those observed in control subjects. The postnatal rise in IGF-I values is presumed to determine the fall in serum GH concentrations by stimulating somatostatin secretion. Neurotensin could be involved as a peripheral signal in the inhibitory mechanisms mediated by release of somatostatin.

Plasma neurotensin levels in prepubertal children and adults: possible involvement in the regulation of growth hormone secretion.

The present study investigated a possible relationship between plasma neurotensin (NT) and serum growth hormone (GH) levels after GH-stimulation provocative tests in humans. Samples were obtained from twelve prepubertal children and sixteen normal adult volunteers. Basal plasma NT levels were higher in children with growth delay (19.02 +/- 4.01 fmol/ml) (mean +/- SEM) than in normal adults (6.13 +/- 1.1 fmol/ml) (p < 0.001). Basal GH levels in children (1.52 +/- 0.06 ng/ml) were not different from those in adults (0.60 +/- 0.41 ng/ml). After stimulation of GH secretion, NT values decreased when GH peaked, and increased when GH levels diminished. These data suggest that plasma NT levels may be involved in the regulation of GH secretion, as a peripheral signal, probably through modulation of somatostatin release from the median eminence.

Modulating effect of human growth hormone on tumour necrosis factor-alpha and interleukin-1beta.

We measured serum tumour necrosis factor-alpha (TNF-alpha) as well as interleukin-1betta (IL-1beta) and GH concentrations in 15 children with isolated growth hormone deficiency (GHD), age range 5.1-13.9 years, before and 4 and 24h after the first GH injection (0.1 IU/kg s.c.). No differences were found in basal concentrations of serum TNF-alpha and IL-1beta between GHD children (10.01 +/- 1.55 pg/ml and 2.14 +/- .16 ng/ml respectively) and sex- and age-matched controls (11.57 +/- 2.16 pg/ml and 3.78 +/- 1.46 ng/ml respectively). In GHD children, serum TNF-alpha and IL-1beta values had significantly increased (P < 0.002) 4h (26.75 +/- 5.57 pg/ml and 2.99 +/- 0.21 ng/ml respectively) and decreased again 24 h after GH administration. Likewise, serum GH levels had significantly increased 4 h (from 1.29 +/- 0.69 to 48.71 +/- 13.35 ng/ml, P < 0.001) and decreased to basal values 24h after GH administration. A significant correlation was found between basal serum concentrations of GH and those of both TNF-alpha (P < 0.01) and IL-1beta (P < 0.05). However, no correlation was found between serum GH concentration and either TNF-alpha or IL-1beta levels 4 and 24h after GH administration. Our data suggest that GH plays a role in modulating TNF-alpha and IL-1beta release in humans.

Apparent functionality but impractical quantification of neurotensin receptors on human peripheral lymphocytes.

Neurotensin (NT), a neuromodulator, is also thought to play an immunomodulatory role. We sought to confirm the effects of NT on proliferation in human peripheral blood lymphocytes (PBLs; n = 10), to characterize the binding properties of the NT receptor using Scatchard analysis, and to measure NT receptors using blood volumes (50 ml) applicable to clinical investigation. Incubation of phytohemagglutinin-stimulated PBLs with NT (10[-10] to 10[-13] M) in the presence of 0.07% normal human serum (72 h at 37 degrees C) significantly enhanced proliferation (p < 0.001), which is consistent with PBLs possessing functional NT receptors. However, the various experimental conditions tested constantly yielded low specific NT binding to human PBLs, and hence Scatchard analysis was impossible for 50-ml blood samples. Our data confirm the existence of a link between NT and the immune system and support a physiological significance for this link. However, measurement of NT receptor binding in readily available cells proved unsuitable for clinical investigation.

Identification of neurotensin-related peptides in human thymic epithelial cell membranes and relationship with major histocompatibility complex class I molecules.

This study shows the expression at the cell surface of human thymic epithelial cells (TEC) of a neurotensin (NT)-like immunoreactivity. NT radio-immunoassay (RIA) revealed that cultured human TEC contain +/-5 ng immunoreactive (ir) NT/10(6) cells, of which 5% is associated with plasma cell membranes. HPLC analysis of NT-ir present in human TEC showed a major peak of NT-ir corresponding to NT1-13. NT-ir was not detected in the supernatant of human TEC cultures. Using an affinity column prepared with a anti-MHC class I monoclonal antibody, NT-ir-related peptides were retained on the column and eluted together with MHC class I-related proteins. According to the elution time on HPLC of these peptides, they correspond to intact NT1-13, as well as to smaller fragments of NT1-13.

Plasma neurotensin levels in humans: relation to hormone levels in diseases involving the hypothalamo-pituitary-thyroid axis.

This study was aimed to investigate, in humans, the possible relationship between plasma neurotensin (NT) levels and the activity of the hypothalamo-pituitary-thyroid axis. Neurotensin was measured by radioimmunoassay in 14 healthy adult volunteers and in 41 patients among whom 10 were considered as controls and 31 had thyroid dysfunction according to free thyroxine and thyrotropin plasma values. Basal NT levels were not significantly different in healthy adults and in control patients: 9.7 +/- 1.1 fmol/ml (mean +/- SEM) vs 13.3 +/- 2.9 fmol/ml, respectively. In patients with central hypothyroidism the NT level was significantly lower (5.7 +/- 1.2 vs healthy volunteers and controls; p < 0.05) and in patients with peripheral hypothyroidism and hyperthyroidism the NT level was significantly higher (35.9 +/- 12.8 and 29.9 +/- 9.5 fmol/ml, respectively, vs healthy adults (p < 0.01) and vs controls (p < 0.05)). After thyrotropin-releasing hormone (TRH) injection (250 micrograms iv) in nine subjects (two control patients, five patients with hypothyroidism and two patients with hyperthyroidism), NT levels decreased independently of the endocrine status from mean values of 13.4 +/- 8.4 at basal level to 7.3 +/- 0.8 fmol/ml 30 min after injection (p < 0.01 on paired percentage decrease values). These data suggest that plasma NT levels in humans depend upon the pituitary-thyroid status and indicate that TRH could exert a negative regulation on circulating NT levels.

Developmental pattern of neurotensin content in rat hypothalamic neurons cultured in serum-free medium: comparison with in vivo data.

Neurotensinergic cells were visualized by immunocytochemistry in rat hypothalamic cultures grown in serum-free medium for 12 days. They represented 0.03% of the total cell population. The pattern observed for the evolution of neurotensin content in hypothalamic cultures, from day 5 to day 21 (7-fold increase), was similar to that observed in the rat hypothalamus during the corresponding period of in vivo ontogeny, from birth to 19 days postnatal (6-fold increase).

Effects of growth hormone administration on neurotensin release in children with growth delay.

Neurotensin (NT), a tridecapeptide originally isolated from bovine hypothalamus, has numerous actions on endocrine functions. Since intravenous injection of NT in the rat stimulated the release of growth hormone (GH) among several pituitary hormones, the aim of our study was to investigate in humans the effects of GH injection on NT plasma levels. Plasma samples were obtained from 13 children with growth delay (7 boys and 6 girls; age range 5 years 1 month-14 years 1 month; mean +/- SE 10 years 9 months +/- 7 months) to evaluate NT and GH values before treatment and 4, 12 and 24 h after a subcutaneous rhGH injection (0.15 IU/kg). Plasma was extracted on a SEP-PAC C18 column and NT was eluted with propanol. NT concentrations were measured by a specific RIA and expressed as fmol/ml plasma. GH (ng/ml) and somatomedin C (SMC; U/ml) were evaluated by RIA using commercial kits. Free fatty acids (FFA; mEq/l) were measured using a colorimetric peroxidase technique. Before GH administration, NT levels were 7.19 +/- 1.01 fmol/ml. A significant increase in NT values was found 4 h (36.5 +/- 9.62, p < 0.001), 12 h (40.85 +/- 6.64, p < 0.001) and 24 h (19.5 +/- 3.48, p < 0.05) after GH injection. This increase was significantly correlated with the circulating GH levels 4 h after GH administration and with the circulating SMC levels 24 h after GH administration. No correlation was found between NT and FFA values.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of interleukins and somatomedins on the production of neurotensin by cell line SH-SY5Y derived from human neuroblastoma]. / Effet des interleukines et des somatomédines sur la production de neurotensine par la lignée cellulaire SH-SY5Y dérivée d'un neuroblastome humain.

The goal of this study was to investigate the regulation by insulin-like growth factors 1 and 2, and interleukins on the production of neurotensin in the SH-SY5Y cell line derived from a human neuroblastoma. Cultures were performed in RPMI1640 culture medium with heated foetal calf serum 12%. After 24 hrs. of fasting without serum, interleukins-1 alpha, IL-2, IL-4 and insulin-like growth factors 1 and 2 were added. Results showed: 1) A mitogenic effect of ILs (p < 0.001) and of IGFs (p < 0.001). 2) The presence of neurotensin in HCl0.1N cellular extracts (0.06 fmol/micrograms protein). 3) The increase of cellular neurotensin content in the presence of IL-4 (560%), IL-2 (480%), IGF-1 (610%) and IGF-2 (200%). Our results indicate that the human neuroblastoma cell line SH-SY5Y produces neurotensin and that ILs and IGFs act in vitro to modulate this production.

Increase of IGF I binding to erythrocyte receptors during the TRH-test: correlation between IGF I binding and thyroid hormone values.

The effects of TRH on insulin-like growth factor I receptors were investigated on erythrocytes from 7 GH-deficient children having plasma GH levels less than 10 ng/ml during two provocation tests. Intravenous injection of synthetic TRH (0.2 mg/m2) was followed by a marked increase of IGF I binding on erythrocytes, from 3.9% +/- 0.3% to 5.9% +/- 0.3% (P less than 0.005) after 1 hour and 7.3% +/- 0.4% (P less than 0.005) after 2 hours. The IGF I binding variations were due to an increase in both the receptor affinity and the number of sites. The levels of plasma GH, IGF I, T3, T4, free T4, TSH and prolactin having been determined during the TRH test at 0, 1 hour, and 2 hours after the injection, the increase in the IGF I binding to erythrocytes at the same time correlated with the rise of thyroid hormones: triiodothyronine T3 (P less than 0.001) and thyroxine T4 (P less than 0.005) and not with the level of the other hormones. These findings suggest that thyroid hormones play a role in the regulation of insulin-like growth factor I receptors.

Production of interleukin-1-alpha and interleukin-2 by mononuclear cells in healthy adults in relation to different experimental conditions and to the presence of growth hormone.

Several reports support the view that the growth hormone (GH) possesses a number of important immunomodulatory properties. This study was undertaken to determine in vitro the role of the GH on interleukin (IL) production. Cultures of blood peripheral lymphocytes obtained from human normal adults were performed in RPMI medium in the presence or absence of phytohemagglutinin (PHA), heated normal serum (NHS) 1% and GH 12.5-500 microgram/l. After incubation from 15 h to 4 days at 37 degrees C in a humidified atmosphere containing 5% CO2, cells were discarded and the supernatants were tested for their contents of IL-1 alpha and IL-2 measured using the Amersham radioimmunoassay system. The results of these in vitro experiments show that: (1) the bulk cultures from peripheral lymphocytes are suitable to study the IL-1 and IL-2 production; (2) in optimal conditions for IL production (incubation during 48 h in the presence of PHA and NHS) no effect of GH was observed on IL production; (3) in the absence of PHA GH acts at physiological doses (less than 100 ng/ml) by increasing the IL production. This effect of GH was optimized with a short time of incubation (16 h) and in the simplest conditions of cultures, that is to say in the absence of serum and of PHA: thus in the presence of GH 100 ng/ml the IL-1 production increases from 0.53 to 3.86 fmol (tubes) and IL-2 increases from 0.18 to 3.22 fmol (tubes). These differences are significant (p less than 0.001). We conclude that GH acts in vitro on mononuclear cells to induce IL production.

Production of interleukin-1 alpha and interleukin-2 by mononuclear cells from children with growth delay in relation to the degree of growth hormone deficiency: effects of substitutive treatment.

Interleukin-1 alpha (IL-1 alpha) and interleukin-2 (IL-2) levels were measured by radioimmunoassay in samples of conditioned medium from mononuclear cells taken from 20 normal subjects (14 adults ranging in age from 20 to 45 years and 6 children ranging in age from 3 to 11 years) and from 49 children with growth delay. Cultures were performed with 10(6) cells/ml in medium containing 1% normal human serum and 4.8 g/l phytohemagglutinin M. The incubation was performed for 48 h in an atmosphere containing 5% CO2. In normal subjects, the production of IL-1 alpha was 38.5 +/- 9.8 fmol/ml of conditioned medium (mean +/- SEM) in 14 adults and 41.6 +/- 3.0 fmol/ml in 6 children. The production of IL-2 was 46.9 +/- 6.5 and 57.3 +/- 10.5 fmol/ml, respectively. In the 16 patients with growth hormone (GH) deficiency studied before treatment, the production of ILs was significantly decreased in relation to the degree of deficiency. We observed a positive correlation between the production of IL-1 alpha and the values of insulin-like growth factor I but not with serum GH values. IL-1 alpha production was normalized after 15 days of substitutive GH therapy and IL-2 was normalized after 3 months of therapy. In 10 other patients with GH deficiency (4 with total and 6 with partial isolated GH deficiency) studied after long-term GH treatment (5 months or more), the mean of IL production was not significantly different from that of GH-deficient children treated for 3 months.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro effect of human growth hormone on lymphocyte transformation and lymphocyte growth factors secretion.

Cultures of human blood peripheral lymphocytes were performed in the presence or absence of human growth hormone, and also of phytohemagglutinin and normal human serum 10%. After incubation for 48 h, the supernatants were tested for their ability to promote the uptake of [3H]thymidine into lectin-activated lymphocytes. Supernatants from lymphocyte-free control samples, treated in the same manner, were assayed under the same experimental conditions. Variance analysis of the different dose-response relationships was performed. The results of these in vitro experiments confirm that physiological levels of GH inhibit the lectin-induced lymphoproliferation and that lymphocytes secrete an 'activity' able to stimulate the incorporation of [3H]thymidine into lectin activated lymphocytes. Furthermore we show that: 1) Secretion of this lymphocyte-stimulating activity is increased by physiological levels of GH; 2) This lymphocytic secretion is not radioimmunoassayable IGF-I; 3) Using fast protein liquid chromatography (FPLC), this activity appears in fractions with various molecular weights.

Effect of biosynthetic methionyl growth hormone (GH) therapy on the immune function in GH-deficient children.

The ability of growth hormone (GH) to influence certain immune functions has been studied in 21 GH-deficient children aged 1.8-17.7 years, before and during therapy with biosynthetic methionyl-hGH (12 IU/m2) injected intramuscularly 3 times weekly. Blood was collected prior to GH treatment, then after 1 week, again at 3-6 months, and finally at 9-12 months of therapy. We studied (1) the distribution of the T lymphocyte subpopulations: T total (CD3), helper/inducer (CD4) and suppressor/cytotoxic (CD8) cells, using monoclonal antibodies (OKT3, OKT4, OKT8) and (2) the in vitro IgM production stimulated by pokeweed mitogen. Pretreatment CD3, CD4, CD8 values were within the normal range. They did not change after 1 week of GH therapy. Following 3-6 months of GH treatment, CD3 significantly increased (p less than 0.001), CD4 decreased (p less than 0.01), CD8 increased (p less than 0.001) and the CD4/CD8 ratio decreased (p less than 0.001). At 9-12 months of therapy, the percentages of the different groups of T cells was not significantly different from the pretreatment values. In vitro IgM production before and following 3-6 months of GH treatment was significantly lower (p less than 0.005) than that of 15 age-matched controls. At 9-12 months, GH therapy restored the in vitro IgM production. No variations in the levels of serum immunoglobulins were observed throughout the treatment period. These data suggest that GH plays a role in the development of the immune function in children.

[GH-dependency of lymphocyte multiplication factor with a low molecular weight]. / GH-dépendance d'un facteur de multiplication lymphocytaire de petit poids moléculaire.

Liquid chromatography (FPLC) separation at pH 6.85 shows that the fractions in human serum which stimulate the multiplication of human lymphocyte are mainly in the 28-42 kd and the 1.3-1.9 kd fractions. The low molecular weight fraction is absent or very low in both GH-deficient and GH-resistant children and T lymphocyte-deficient children, and appears after appropriate treatment, i.e. GH or marrow transplantation. The data suggest the GH-dependency of 1.3-1.9 kd factor(s) produced by immuno-competent lymphocytes.

Immunological and endocrinological response to growth hormone therapy in short children.

We investigated the influence of human growth hormone (hGH) on mitogen-stimulated lymphoproliferation, in vitro IgM production, serum levels of immunoglobulins, somatomedin-C (Sm-C) values and serum growth-promoting activity (Thymidine Activity, TA) in 18 short children, aged between 6.6-14.5 years, undergoing a 3-month course of hGH therapy. Blood was collected the day before treatment (Group A), on the 5th day after patients were administered hGH daily (0.1 U/kg) i.m. for 4 days (Group B), after a 3-month course of hGH injected three times weekly, and finally before (Group C) and 24 h after an extra injection (Group D). In vitro IgM production from the patients' unstimulated lymphocytes decreased from 277 +/- 41 (Group A) to 168 +/- 38 (Group B), to 119 +/- 43 (Group C) and then to 119 +/- 28 ng/ml (Group D) (p less than 0.05). Using PWM-stimulated lymphocytes in vitro IgM production decreased from 2,015 +/- 464 (Group A) to 1,116 +/- 316 (Group B), then to 511 +/- 170 (Group C) and 968 +/- 295 ng/ml (Group D) (p less than 0.02). The variation of this decrease could be correlated with the variation of growth velocity during treatment (r = 0.619, p less than 0.05). In contrast, no significant changes were found following therapy either in serum levels of IgA, IgE, IgG, IgM, Sm-C and TA, or in phytohemagglutinin, concanavalin A and pokeweed mitogen-stimulated lymphoproliferation. Our data suggest that there is some relationship between growth hormone, growth and immunity.

Insulin-like growth factor I receptors on human erythrocytes from normal children: relationship with age.

The binding of insulin-like growth factor I (IGF I) on red blood cells has been studied in 13 children aged 8 months to 11 years and in 10 adults. The Scatchard analysis showed a curvilinear regression. In adults, the specific binding was 4.1% of the tracer, the mean number of high affinity receptor sites per cell (Ro1) being 0.88 (K1 = 10.74 nM-1) and the mean number of low affinity receptors sites (Ro2) per cell being 7.14 (K2 = 0.37 nM-1). In children the specific binding ranged from 3 to 6.5%. Ro1 ranged from 0.40 to 3.13 (K1 from 3.48 to 13.61 nM-1). Ro2 ranged from 2.88 to 17.25 (K2 from 0.03 to 0.65 nM-1). The most striking fact was the close positive correlation between the specific binding and the age of children (r = 0.914, P less than 0.001). These data suggest that the high growth velocity of young children, concomitant with the low plasma levels of IGF I which are physiological during infancy and early childhood, does not result from an increased binding of IGF I to cell receptors.