Plasma Human Growth Hormone Research Articles

A combined top-down and bottom-up LC-HRMS/MS method for the quantification of human growth hormone in plasma and serum

ObjectiveThe precise and accurate quantification of human growth hormone (GH) in plasma/ serum is crucial for the diagnosis and treatment of diseases like GH deficiency or acromegaly. However, the ligand-binding assays (LBAs) currently used for routine testing show considerable methodological variability. Here, we present a complementary, combined top-down and bottom-up LC-MS-based method to quantify (intact) GH in plasma and serum, which concurrently provides a basis for a MS-based analysis of GH in doping controls. DesignExtraction of GH from plasma/ serum was accomplished by protein precipitation, followed by an immunocapture step using protein A-coupled magnetic beads and a polyclonal anti-GH antibody. The intact protein was subsequently analyzed top-down on a 2D-LC-HRMS/MS system. In addition, sample extracts were digested with trypsin and analyzed for signal peptides corresponding to ‘total’, 22 kDa and 20 kDa GH (bottom-up). Both assays were validated according to current guidelines and compared to the GH isoform differential immunoassay used in routine doping control analysis. GH concentrations in serum samples of healthy adults, patients with acromegaly, and in samples obtained after administration of recombinant GH were analyzed as proof-of-principle. ResultsThe intact monomeric 22 kDa isoform of GH was selectively quantified in a representative working range of 0.5 to 10 ng/ml by top-down LC-HRMS/MS. Subsequent bottom-up analysis provided additional data on ‘total’ and 20 kDa GH. Top-down and bottom-up assay results for the 22 kDa isoform correlated well with the corresponding immunoassay results (R2 > 0.95). For a possible application of the method in an anti-doping context, the ratio between 22 kDa and ‘total’ GH was evaluated, indicating differences between the various donor groups, but only with limited significance. ConclusionThe top-down and bottom-up LC-HRMS/MS method developed here presents a valuable tool for the quantification of GH in plasma/ serum complementary to established LBAs used at present in clinical measurements. Albeit the examination of the GH isoform proportions by the LC-MS method does not yet allow for the assessment of GH abuse, the obtained findings provide an important basis to enable LC-MS-based GH analysis of doping control samples in the future.

Do anabolic nutritional supplements stimulate human growth hormone secretion in elderly women with heart failure?

Growth hormone treatment has gained attention over the past decade as a treatment for heart failure. Human growth hormone (HGH) must be administered by injections (usually daily), so there is considerable advantage to stimulation of endogenous secretion by amino acid‐based nutritional supplementation. However, studies investigating the effect of amino acid (AA) supplementation show conflicting results. Therefore, in this study we aimed to investigate the effect of nutritional supplementation on HGH production in elderly women with heart failure. Eight elderly women with heart failure participated in this randomized cross‐over study. Plasma HGH concentration was measured before and for 4 h following ingestion of a mixture of protein, carbohydrate, and fat or an AA beverage. HGH concentration was determined with ELISA kits and AA concentrations were analyzed by Liquid Chromatography–Mass Spectrometry (LCMS). Linear mixed models was performed to analyze the effect of time, treatment, and interaction. Plasma arginine and lysine concentrations were significantly higher after consumption of the AA drink compared to the mixture of protein, carbohydrate, and fat. Nonetheless, only ingestion of the protein, carbohydrate, and fat mixture (meal replacement) increased HGH concentration. HGH concentration was increased in elderly women with heart failure following consumption of a meal replacement containing protein, carbohydrate, and fat. Consumption of a mixture of amino acids failed to increase HGH concentration despite significantly greater elevations in plasma amino acid concentrations, including arginine and lysine. The stimulatory effect of the protein/carbohydrate/fat mixture was presumably mediated by factors other than increases in free amino acid concentrations.

Effects of 24-hour Food Restriction on Plasma Human Growth Hormone, IGF-1, Cortisol and Testosterone Responses in Resistance Exercise

Effects of 24-hour Food Restriction on Plasma Human Growth Hormone, IGF-1, Cortisol and Testosterone Responses in Resistance Exercise

Effects of a Pre-Exercise Meal on Plasma Growth Hormone Response and Fat Oxidation during Walking

The purpose of this study was to determine the effects of a pre-exercise meal on the plasma human growth hormone (hGH) response and fat oxidation during walking. Subjects (n=8) were randomly provided with either 1 g/kg body weight of glucose in 200 mL water (CHO) or 200 mL water alone (CON) 30 min prior to exercise and subsequently walked on a treadmill at 50% of VO2max for 60 min. Plasma hGH concentrations were significantly higher in subjects who received CHO compared to those who received CON at 15 and 30 min. The fat oxidation rate in the CHO was significantly lower than the CON while walking for 5~15, 25~35 and 45~55 min. Plasma FFA levels were also significantly lower in the CHO compared to the CON at 30, 45 and 60 min. Plasma glucose levels in the CHO were significantly lower while plasma insulin levels were significantly higher than in the CON at 15 and 30 min. Therefore, the results of this study suggest that the elevation of plasma hGH levels due to the intake of a pre-exercise meal may not be strongly related to fat oxidation and plasma free fatty acid (FFA) levels during low-intensity exercise.

Insulin-like growth factor-I and alpha 2-macroglobulin in seminal plasma correlate with semen quality.

Insulin-like growth factor-I (IGF-I) and alpha 2-macroglobulin (alpha 2-M) are believed to be involved in the development of germ cells. IGF-I is mainly controlled by concentrations of human growth hormone (HGH), influences cell proliferation and differentiation and its action is mediated by insulin-like growth factor-binding proteins (IGFBP), placental protein 14 (PP14) and prostate-specific antigen (PSA). alpha 2-M acts as a broad spectrum proteinase inhibitor and a binding protein for many cytokines and hormones, e.g. inhibin and activin. This study was designed to identify concentrations of these molecules in seminal plasma in normal semen samples of healthy men, correlations with semen quality, the relationship of IGF-I and alpha 2-M with factors affecting male fertility, and whether vasectomy influences the concentrations of these molecules. Concentrations of IGF-I and alpha 2-M in human seminal plasma were related to semen quality, basal concentrations of HGH, testosterone, IGFBP-3, soluble fibronectin receptor (sFNR), PSA and PP14 in seminal plasma and to serum concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH). Commercially available assays were used to analyse 69 semen samples of various quality and 11 post-vasectomy samples. IGF-I concentrations in seminal plasma were significantly correlated with the percentage of morphologically normal spermatozoa (r = 0.748, P = 0.00001) and sperm concentration (r = 0.301, P = 0.011), but negatively correlated with serum FSH (r = -0.506, P = 0.00006) and PSA in seminal plasma (r = -0.388, P = 0.00009). Total alpha 2-M was significantly correlated with sperm count (r = 0.423, P = 0.0005), percentage of progressively motile spermatozoa (r = 0.444, P = 0.00019), quality of motility (sperm motile efficiency, r = 802, P = 0.00001) and straight line velocity (r = 0.411, P = 0.0013). Correlation between the sperm concentration and HGH in seminal plasma was weak (r = 0.287, P = 0.015). Vasectomy reduced the concentration of total alpha 2-M (P = 0.00008) and HGH (P = 0.0068) in the seminal plasma; IGF-I was also reduced after vasectomy when the total ejaculate amount was considered. Thus IGF-I and alpha 2-M are significant for the germ cell development: IGF-I in the maturation of spermatozoa and alpha 2-M in progressive motility.

Threshold increases in plasma growth hormone in relation to plasma catecholamine and blood lactate concentrations during progressive exercise in endurance-trained athletes.

Plasma human growth hormone ([HGH]), adrenaline ([A]), noradrenaline ([NA]) and blood lactate ([La-](b)) concentrations were measured during progressive, multistage exercise on a cycle ergometer in 12 endurance-trained athletes [aged 32.0 (SEM 2.0) years]. Exercise intensities (3 min each) were increased by 50 W until the subjects felt exhausted. Venous blood samples were taken after each intensity. The [HGH] and catecholamine concentrations increased negligibly during exercise of low to moderate intensities revealing an abrupt rise at the load corresponding to the lactate threshold ([La-]-T). Close correlations (P <0.001) were found between [La-]b and plasma [HGH] (r = 0.64), [A] (r = 0.71) and [NA] (r = 0.81). The mean threshold exercise intensities for [HGH], [A] and [NA], detected by log-log transformation, [154 (SEM 19) W, 162 (SEM 15) W and 160 (SEM 17) W, respectively] were not significantly different from the [La-]-T [161 (SEM 12) W]. The results indicated that the threshold rise in plasma [HGH] followed the patterns of plasma catecholamine and blood lactate accumulation during progressive exercise in the endurance-trained athletes.

Branched Chain Amino Acid (BCAA) Chronic Treatment and Plasma Human Growth Hormone (HGH) after Physical Exercise in Triathlon Athletes

Branched Chain Amino Acid (BCAA) Chronic Treatment and Plasma Human Growth Hormone (HGH) after Physical Exercise in Triathlon Athletes

Growth hormone-releasing activity of growth hormone-releasing peptide-1 (a synthetic heptapeptide) in children and adolescents

The heptapeptide growth hormone-releasing peptide-1 (GHRP-1), one of a series of recently synthesized small growth hormone (GH)-releasing peptides, was administered as an iv bolus (1 microgram/kg) to 15 (six prepubertal, nine pubertal) short but healthy children and adolescents and to eight juvenile patients with pituitary insufficiency (four with isolated growth hormone deficiency, two with multiple pituitary hormone deficiencies, one with partial GH deficiency and one with GH-releasing hormone (GHRH) deficiency). Eleven out of 23 subjects also underwent an in GHRH (1-29) test (1 microgram/kg). All the healthy children responded with a progressive rise in plasma human GH (hGH) peaking at 15-30 min, with a significantly higher rise (p < 0.05) in the pubertal than prepubertal group. The hGH response to GHRH (1-29) in these children was similar or slightly higher. Six hypopituitary patients had no response to either GHRP-1 or GHRH; the patient with partial GH deficiency had a hGH peak of 6.5 micrograms/l (at 5 min) to GHRP-1 and 9.2 micrograms/l (at 15 min) to GHRH. One patient had no response of hGH to hypoglycemia, clonidine and GHRP-1, but the plasma hGH rose to 10 micrograms/l after GHRH. Following the GHRP-1 bolus there was a significant (p < 0.01) rise in plasma free thyroxine and a decrease of thyrotropin (p < 0.01), both in the limits of normal values. There was also a transitory rise of plasma cortisol (p < 0.05). Plasma prolactin, luteinizing hormone and follicle-stimulating hormone did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Human Plasma Growth Hormone (GH)-Binding Proteins Are Regulated by GH and Testosterone*

Possible regulation of GH-binding proteins (GH-BPs) in human plasma was examined. Eight children with isolated GH deficiency had a very low level of plasma GH-binding activity (10.2 +/- 1.1% of radioactivity). Under GH treatment the hormone binding to the high affinity BP (peak II-BP) increased in every patient to reach the mean value of 18.5 +/- 1.4%. In one patient, Scatchard plot analysis indicated that this increase was related to a higher binding capacity without any significant change in the binding affinity. A positive correlation existed between the GH-binding activity and insulin-like growth factor-I plasma levels. In nine boys with pubertal delay, the GH-specific binding to peak II-BP was normal (30.6 +/- 3.7% of radioactivity); it decreased significantly after testosterone treatment. In four boys with precocious puberty, the specific GH binding to peak II-BP was low (16.6 +/- 1.1%). It increased significantly to 21.6 +/- 1.1% of radioactivity after treatment with a LHRH analog. A negative correlation existed between plasma testosterone levels and GH binding to peak II-BP in boys presenting pubertal delay or precocious puberty. The high affinity GH-BP is regulated, and among the factors that play a role in this regulation, GH and testosterone have opposite effects.

Impact of human growth hormone on plasma lipoprotein concentrations.

To evaluate whether the moderately elevated human growth hormone concentration, seen in insulin dependent diabetic patients, has any impact on lipoproteins, human growth hormone was given to nondiabetic persons in doses which would bring their plasma human growth hormone concentration up in the same level as seen in insulin dependent diabetic patients. After one week of treatment with human growth hormone we found total plasma triglyceride to be significantly raised (0.98 mmol/l +/- 0.28 mmol/l (mean +/- SD) before versus 1.27 mmol/l +/- 0.38 mmol/l (mean +/- SD) after treatment). Very low density lipoprotein (VLDL) was separated into two fractions (VLDL-1 and VLDL-2) of which VLDL-2 is regarded as a VLDL-remnant which is suggested to be of importance for development of atherosclerosis. After one week of human growth hormone treatment there were no changes in VLDL-1 concentrations whereas a significant raise in VLDL-2 triglyceride and VLDL-2 cholesterol was seen.

Action of trimipramine on sleep and pituitary hormone secretion.

Trimipramine is unlike other antidepressants in that it does not suppress REM sleep and possesses an atypical pharmacological profile. This antidepressant was administered in the evening to 10 depressed patients at a dosage of 75 mg on night 1 with 25 mg increments each night, up to 200 mg on night 6 and at this dosage thereafter. Sleep parameters were measured at baseline and on nights 2, 11 and 21. On nights 11 and 21, there was a significantly improved sleep pattern as shown by increases in sleep period time, total sleep time and sleep efficiency, and there was a decrease in sleep onset latency. No suppression of REM sleep occurred, and an increase was even noted; this, however, may have been due to a particularly low baseline value. Subjective assessments in which self-ratings of sleep quality were used also demonstrated an improvement in sleep. In addition, the neuroendocrine effects of trimipramine were investigated in 8 healthy volunteers after a single oral 75 mg dose. After 3 hours, a significant fall in plasma cortisol concentration from 117 to 43 micrograms/L and a significant rise in plasma prolactin concentration from 6 to 16.3 micrograms/L were observed, but there was no significant effect on plasma human growth hormone concentration. These results further support the effectiveness of trimipramine therapy in normalising a disturbed sleep pattern in depressed patients, and it may be of use in non-depressed insomniacs. The acute neuroendocrine effects of trimipramine are similar to those observed with neuroleptics and further indicate its atypical pharmacological profile.

Correlates of lateral ventricular size in chronic schizophrenia, II: biological measures

CSF homovanillic acid levels showed a significant negative correlation with ventricle-brain ratios (VBRs) in a group of drug-free chronic schizophrenic male veterans, while CSF 5-hydroxyindoleacetic acid levels showed a similar, nearly significant trend. The response of plasma human growth hormone to 0.75 mg of apomorphine also demonstrated a significant negative correlation with VBR in this group, but other measures of central neurotransmitter activity were unrelated to ventricular size.

Diurnal rhythm of plasma beta endorphin, cortisol and growth hormone in schizophrenics as compared to control subjects.

The diurnal variation of plasma beta endorphin was studied in ten schizophrenics, and in age/sex matched control subjects. In the controls beta endorphin was high in the morning (21.0 +/- 3.5 pmol/l) and decreased towards evening. In the schizophrenic group the beta endorphin fluctuated randomly, ranging within 9-40 pmol/l throughout the day. Plasma cortisol showed a normal diurnal pattern in both groups. The mean plasma cortisol levels in the schizophrenics were significantly higher than in the controls throughout the day. The pattern of plasma human growth hormone (hGH) level was similar in both groups at the time tested. It is hypothesized that the instability of beta endorphin secretion may contribute to the pathogenesis of schizophrenia.

Decrease in human growth hormone (HGH) levels during transsphenoidal surgery for acromegaly as a guide for prognosis.

To evaluate the clinical significance of human growth hormone (HGH) dynamics during transsphenoidal microsurgery for acromegaly, serial HGH levels during the surgery were compared with the post-operative basal HGH levels in 15 acromegalic patients, retrospectively. In all patients, in whom the HGH level immediately after tumor resection was reduced below 5 ng/ml or the decreasing rate which stood for the magnitude of decrease of HGH during resection procedure was above 80%, postoperative permanent HGH levels fell to below 5 ng/ml, namely, within the normal range. The rapid radioimmunoassay (RIA) of HGH was developed by the use of high affinity antibody in order to inform the surgeons of plasma HGH levels quickly during the surgery. It is now possible to know HGH levels about 1 hour after submitting the samples. It was verified that HGH levels measured in the rapid RIA correlated well with those obtained in the conventional way. The rapid RIA method was applied to 6 patients and the correlation between HGH levels during the surgery and post operative levels was also studied prospectively. The results were essentially identical to those in a retrospective study. It was suggested that the HGH level immediately after tumor resection and the extent of the decrease in HGH during the resection procedure were good indicators of the prognosis of surgical results in acromegaly and the rapid RIA method was useful in order to judge HGH levels quickly during the surgery.

Failure of bromocriptine to alter the qualitative characteristics of human growth hormone in acromegaly

The role of bromocriptine as a therapeutic agent for acromegaly is uncertain. In the present study we have attempted to determine whether bromocriptine therapy causes qualitative changes in plasma human growth hormone (hGH) in acromegaly. When eight paired samples obtained before and during bromocriptine therapy were filtered over Sephadex G-100 there was no difference in the elution profiles. When the “little” hGH peak from each of the eight paired samples was pooled, lyophilized, and assayed in both radioreceptor assay (RRA) and radioimmunoassay (RIA), the RRA RIA before treatment was not different than during treatment. When bromocriptine in pharmacologically significant concentrations was incubated with cultured human lymphocytes in vitro, there was no alteration in hGH binding properties. These results demonstrate directly that bromocriptine does not change the form or receptor-reactive properties of plasma hGH and, further, that the drug does not alter at least one form of human growth-hormone receptor.

Basal plasma HGH and cortisol levels and the effect of clonidine administration in female migrainous patients.

Clonidine, a central alpha-adrenergic agent and prophylactic antimigraine drug is known to stimulate human growth hormone (HGH) release and to suppress cortisol secretion. A possible association between basal hormonal levels and response to either acute clonidine test or chronic treatment in female migrainous patients was investigated. 15 females, aged 18-43 years, suffering from migraine, underwent an acute clonidine test by administration of a single oral dose of 0.15 mg. High basal HGH levels (greater than or equal to 9 ng/ml) were observed in 6 patients, while the other 9 patients demonstrated normal low basal HGH levels. Acute clonidine administration induced a marked rise of HGH in 8 of the 9 patients with low basal HGH. In 4 of the 8 responders HGH levels exceeded 20 ng/ml and 3 subjects reached the acromegalic range (greater than 90 ng/ml). The mean response in this group was higher than in a reference group consisting of children and adolescents. It is suggested that the basal hypersecretion and the hyperresponsiveness of HGH to clonidine provocation test in some migrainous patients results from a hypersensitivity of the central alpha-adrenergic receptors. 12 of the 15 females were treated for 10 weeks with clonidine at gradually increased doses of 0.05 mg/day up to a maximal dose of 0.15 mg/day. A marked suppressive effect on cortisol secretion was observed in the migrainous patients after acute and chronic administration of clonidine. No correlation was observed between HGH and cortisol response to acute or chronic clonidine administration and the prophylactic effect of clonidine on migraine.

Acute and Chronic CLonidine Treatment in Tourette's Syndrome: A Preliminary Report on Clinical Response and Effect on Plasma and Urinary Catecholamine Metabolites, Growth Hormone, and Blood Pressure

Tourette's syndrome (TS) is a chronic neuropsychiatric disorder of unknown etiology characterized by simple and complex motor and phonic symptoms and behavioral difficulties. Clonidine, an α 2-adrenergic receptor agonist, is useful in the treatment of TS. We report the preliminary results of a series of biological studies undertaken during an open 12-week clinical trial of oral clonidine (2–3 μg/kg/day) in six TS patients. These studies focus on the functional status of central noradrenergic and dopaminergic systems. Specifically, we report the effectgs of a single dose of clonidine (3 μg/kg) p.o., given under double-blind, placebo-controlled conditions, on plasma-free and urinary total 3-methoxy-4-hydroxyphenthyleneglycol (MHPG), plasma homovanillic acid (HVA), plasma human growth hormone (HGH), blood pressure, and sedation under baseline conditions, and after 12 weeks of clonidine therapy. The data do no clearly support the hypothesis that presynaptic noradrenergic receptors are subsensitive in TS or that chronic clonidine treatment increases their sensitivity. However, a significant increase in baseline HVA following chronic clonidine treatment was observed. These preliminary findings are suggestive of a central noradrenergic-dopaminergic interaction in TS. In addition, the clinical response data at 12 weeks, 10–12 months, and following double-blind, placebo-controlled withdrawal of clonidine are presented, and the usefulness of the pretreatment biological measures in predicting the clinical response to clonidine is assessed.

Normal variant short stature.

Human Growth hormone (HGh) deftciency is a well recognized cause of short stature and the criteria for its diagnosis is well established. ! From time to time patients not considered to be HGh deficient by the traditional criteria have been said to benefit from treatment with HGh, but have not been systematically studied. 2 Recently a group of children with short stature has been identified who, though not full'riling the usual criteria for HGh deficiency, benefit from HGh therapy. 3 This condition has recently been termed "normal variant short stature" (NVSS), a term first used by David Smith 4 and popularized by Rudman and associates. 3 The criteria for diagnosing NVSS include (i) current height and predicted adult height below the 3rd percentile, (ii) birth weight greater than 2500 gin, (iii) normal physical examination except for proportionate short stature with or without retarded bone age, (iv) no evidence of economic, psychological or nutritional deprivation, (v) average peak plasma HGh value of more than 12 ng/ml in the provocative tests, (vi) normal thyroid, adrenal and antidiuretic hormone function and (vii) a normal karyotype. 3

Effect of acute selective beta-1-adrenoceptor blockade on hormonal and cardiovascular response to insulin-induced hypoglycaemia in insulin-dependent diabetic patients

The hormonal and cardiovascular responses to intravenous (i.v.) insulin were studied in 16 insulin-dependent normotensive diabetic patients after acute injection of selective beta-1-adrenoceptor blocking agents. The lowest blood glucose levels were not affected by beta-1-adrenoceptor blockade while the time for reaching nadir was significantly reduced. Plasma adrenaline levels increased significantly during selective beta-1-adrenoceptor blockade. Plasma noradrenaline, glucagon and human growth hormone levels, however, remained unaffected. The insulin-induced tachycardia was not prevented by the beta-1-blockade, and the mean arterial blood pressure was unchanged. The ability to recognize the symptoms of insulin-induced hypoglycaemia persisted in all patients, although less pronounced in nine of them. We suggest that selective beta-1-adrenergic blocking agents may be employed without risk in the treatment of hypertensive insulin-dependent diabetic patients.

Plasma prolactin in acromegaly before and after treatment.

Plasma human prolactin (hPRL) was measured in 73 untreated acromegalic patients and was found to be elevated in 32% of the total population. Hyperprolactinemia was present in 40% of the females and in 27% of the male patients. In both groups, plasma hPRL correlated with plasma human growth hormone (hGH) levels with correlation coefficients of 0.38 (P less than 0.05) for females and 0.41 (P less than 0.005) for males. Forty-five patients were treated with conventional supervoltage pituitary irradiation and evaluated 2, 5, and 10 yr after treatment. The patients with hyperprolactinemia before irradiation showed a decrease in plasma hPRL at the most recent follow-up (mean +/- SEM, 125 +/- 34 vs. 67 +/- 15 ng/ml; P less than 0.01), although, in general, they did not achieve normal values. The patients who had normal plasma hPRL before irradiation (mean +/- SEM, 14 +/- 2 ng/ml) had increased levels after therapy (23 +/- ng/ml; P less than 0.005) but remained in the normal range during long term follow-up. In 10 patients followed for 1-10 yr without treatment, there was a tendency for plasma hPRL to rise progressively (mean increment, 122% above the initial value), with individual changes in hPRL strikingly parallel to the changes in plasma hGH. When serum hPRL was initially elevated, similar responses in both hormones were also seen in a small group of patients treated with surgical hypophysectomy. Galactorrhea was present in 5 of the 25 female patients; in 4 of the 5, plasma hPRL was within the normal range. Overall, these data suggest a closer relationship between hGH and hPRL in acromegaly than had been suspected, not only at the level of pituitary secretion but possibly also at the target cell.