Water immersion increases the concentration of the immunoreactive N-terminal fragment of proatrial natriuretic factor in human plasma

Atrial natriuretic factor (ANF) N-terminal (ANF 1-98) and C-terminal (ANF 99-126) fragments were determined by radioimmunoassay in human plasma. Mean basal plasma ANF N-terminal concentrations in 9 healthy subjects were 461 +/- 58 fmol/ml, significantly (p less than 0.0001) higher than ANF C-terminal concentrations (4.8 +/- 0.5 fmol/ml). Central volume stimulation by one hour head-out water immersion (WI) induced a significant (p less than 0.01) increase of the C-terminal peptide levels to 11.6 +/- 2.3 fmol/ml, paralleled by a significant (p less than 0.001) increase of the N-terminal fragment levels to 749 +/- 96 fmol/ml. Increases of plasma concentrations of both fragments upon WI correlated significantly (r = 0.71; p less than 0.05). These data suggest cosecretion of the N-terminal fragment with the C-terminal fragment of pro ANF 1-126 following a physiological stimulus of ANF release in man.     

A sensitive radioimmunoassay of alpha human atrial natriuretic polypeptide using monoclonal antibody recognizing human form ring structure

A monoclonal antibody (C351) against alpha human atrial natriuretic polypeptide (alpha hANP) recognizing human form ring structure was established and applied to a radioimmunoassay of plasma alpha hANP. The minimum detectable amount in terms of 10% radioligand displacement relative to zero dose were 0.28 fmol/tube, corresponding to 0.7 fmol/ml in plasma after extraction using Sep-Pak C18 cartridges. When the mean plasma levels at recumbent position in fasted morning were compared in 10 young (less than 30 years) and 10 elderly (greater than or equal to 50 years) healthy subjects taking normal sodium diet, it was slightly higher in the latter (3.2 +/- 0.4 vs 4.7 +/- 0.5 fmol/ml, mean +/- SE, p less than 0.05). After i.v. infusion of hypertonic saline (2.5% NaCl) at a rate of 0.24 ml/kg/min for 20 min in 6 normal subjects (26 to 35 years), it was increased from 4.1 +/- 0.4 to 5.9 +/- 0.7 fmol/ml (p less than 0.01). In 6 patients with essential hypertension (34 to 57 years), it was elevated with high salt intake, i.e. 3.3 +/- 0.3, 3.9 +/- 1.03 and 7.6 +/- 1.5 fmol/ml under 34, 170 and 340 mEq NaCl/day for 7 days, respectively. From these results, the radioimmunoassay of plasma IR-alpha hANP using MAb C351 seems to be quite suitable to detect rather small changes at low plasma concentrations and to investigate a physiological importance of alpha hANP in man.     

The heart is a source of circulating cardiotrophin-1 in humans

Cardiotrophin-1 (CT-1) is a new member of the interleukin (IL)-6 family of cytokines and one of the endogenous ligands for gp130 signaling pathways in the heart, which has potent hypertrophic and survival effects on cardiac myocytes. However, the clinical significance of CT-1 is poorly understood, mainly because there is no widely applicable specific and sensitive assay system for measuring plasma levels of circulating CT-1. We therefore developed a competitive radioimmunoassay (RIA) for human CT-1 with rabbit antiserum recognizing the N-terminus region of human CT-1 and using recombinant human CT-1 as a calibrator. The assay displays no cross-reactivities with any of the IL-6 family of cytokines including IL-11, leukemia inhibitory factor, ciliary neurotrophic factor, and oncostatin M. The lower detection limit in buffer was found to be 43 fmol/ml, and the working range was 120-8300 fmol/ml (CV < 15%). This RIA directly recognizes CT-1-like immunoreactivity in human plasma with a mean value of 571 +/- 75 fmol/ml (mean +/- SD) in healthy volunteers. The RIA coupled with gel filtration chromatographic analyses showed that the major molecular form of circulating CT-1 corresponds to recombinant full-length human CT-1. Moreover, there is a significant increase in the plasma CT-1 concentration from the aorta and coronary sinus, which clearly indicates that the heart secretes CT-1 via the coronary sinus into the peripheral circulation. This RIA should serve as a powerful tool for investigating the clinical significance of CT-1.     

Effect of acute exercise on plasma neurotensin levels

Neurotensin (NT) levels were examined in five aerobically untrained females aged 20-36 engaged in acute graded exercise testing. In addition to radioimmunoassay measurements, high pressure liquid chromatography was performed to further characterize plasma NT-like immunoreactivity (NTLI). Epinephrine (E), norepinephrine (NE), and lactate (L) responses were also determined. Exercise testing consisted of one hour of treadmill running subdivided into three 20-minute segments representing 50, 60, and 70%, respectively, of the previously determined maximal aerobic capacity. Mock testing established baseline values for each subject. Three components of NTLI were evaluated: NT(1-13), NT(1-8), and NT(1-11). Resting NT(1-13) concentrations averaged 5.8 +/- 4.2 fmol/ml, while mean NT(1-8) values were 13.0 +/- 5.2 fmol/ml, and NT(1-11) averaged 5.8 +/- 3.2 fmol/ml. Peak exercise values were: for NT(1-13), 5.4 +/- 2.0 fmol/ml, for NT(1-8), 13.5 +/- 2.8 fmol/ml, and for NT(1-11), 5.9 +/- 0.5 fmol/ml. Analysis of variance with repeated measures detected no changes in these levels with exercise. Four-fold increases in E (36 +/- 3 pg/ml to 121 +/- 51 pg/ml), NE (340 +/- 95 pg/ml to 1431 +/- 319 pg/ml), and L (0.8 +/- 0.1 mM to 4.3 +/- 1.7 mM) confirmed the stress of exercise on the body in general, and the sympatho-adrenal system in particular. While other research has associated peripheral NT metabolite elevations with stressful stimuli in laboratory animals, the results of the present study suggest either that NT is not released from the human adrenal medulla during exercise, or that peripheral sampling precludes detection of any increases in NT from the adrenal medulla with currently available radioimmunoassay systems.     

Presence of the atrial natriuretic factor (ANF) in human ascitic fluid

Presence of atrial natriuretic factor (ANF)-like material was demonstrated by radioimmunoassay in ascitic fluid of 14 patients with cirrhosis of the liver. Immunoreactive ANF concentrations (M +/- SEM) were 2.4 +/- 0.5 fmol/ml in ascites, significantly lower (p less than 0.001) than the corresponding plasma concentrations of 15.5 +/- 2.6 fmol/ml. High performance gel permeation chromatography and reverse phase high performance chromatography of the ascitic ANF immunoreactivity showed correspondence to the alpha human ANF (99-126). ANF levels in ascites were significantly (p less than 0.01) correlated to levels in plasma (r = 0.66).     

Beta-endorphin-like and alpha-MSH-like immunoreactivities in human milk

We measured with radioimmunoassay the beta-endorphin-like and alpha-MSH-like immunoreactivities in milk and plasma of 8 lactating women. Mean beta-endorphin concentrations ( +/- SD) were 16.6 +/- 6.7 fmol/ml in milk and 9.9 +/- 4.1 fmol/ml in plasma. alpha-MSH concentrations (mean +/- SD) were 39.4 +/- 15.5 pg/ml in milk and 18.2 +/- 8.4 pg/ml in plasma. The concentrations of both peptides in milk were significantly (p less than 0.05) higher than in plasma. No significant correlation between milk and plasma concentrations of these peptides was found.     

Brain natriuretic peptide-like immunoreactivity is present in human plasma

A highly specific and sensitive radioimmunoassay (RIA) for a novel porcine brain natriuretic peptide (BNP) has been established to elucidate whether BNP-like immunoreactivity (LI) is present in human plasma. The antibody used was specific for BNP without any crossreactivities with known human atrial natriuretic peptides (hANP). After extraction of human plasma with Sep-Pak cartridge, this assay allowed for detection of BNP-LI as low as 0.1 fmol/tube. In 12 healthy subjects, the mean concentrations of plasma BNP-LI were 1.5 fmol/ml. Reverse-phase HPLC coupled with BNP RIA revealed that the single major component with BNP-LI, corresponding to porcine BNP(1–26), was apparently distinct from that of -hANP. These data indicate that a small molecular mass form with BNP-LI circulates in human blood.     

A simplified radioimmunoassay for physiologically active angiotensin peptides [(1-8) octa- and (2-8) heptapeptides]

The availability of a sensitive and highly specific rabbit antiserum and the development of a peptide-extraction method employing glass beads permitted the evolution of a rapid reliable radioimmunoassay that measures the sum of the concentration of angiotensin II and its active metabolite, angiotensin III. At a dilution of 1:32,000 the antiserum is capable of measuring 1 fmol (1 pg) of angiotensin II. Cross reactivities of this antiserum, taking angiotensin II as 1.0, are: angiotensin III, 0.75; angiotensin-(3-8) hexapeptide, 0.11; angiotensin I, 0.006; angiotensin-(1-14) tetradecapeptide, 0.0001. The recovery of angiotensin II added to hormone-free plasma was 73 +/- 2% [mean +/- standard deviation (SD), n = 20]. When 0.9 ml of plasma was extracted, the minimal concentration of angiotensin II and III that could be quantified was 4 fmol/ml. When larger volumes of plasma were extracted, sensitivity was enhanced. Plasma blanks were zero. Intra-assay variability was 7.6% SD and interassay variability was 11.7% SD. Angiotensin II and III concentration in venous plasma of normal volunteers on an ad libitum diet was 15 +/- 8 fmol/ml (mean +/- SD, range less than 4 to 35 fmol/ml). The plasma of a patient with primary aldosteronism had an unmeasurable value (less than 4 fmol/ml). Posture, converting enzyme inhibition, and renal artery stenosis resulted in expected changes of angiotensin concentration.     

Quantification of BK1-5, the stable bradykinin plasma metabolite in humans, by a highly accurate liquid-chromatographic tandem mass spectrometric assay

Bradykinin is a vasoactive nonapeptide involved in cardiorenal physiology and inflammatory states. It has been linked to the pathophysiology of hypertension and diabetes. Correlating levels of bradykinin with disease states has been hampered by its rapid degradation, artifactual production during blood sampling, and nonspecific radioimmunoassay techniques. We previously identified BK1-5 as the stable in vivo plasma metabolite of systemic bradykinin in humans. We now report a sensitive and specific assay method for BK1-5 in human blood utilizing liquid chromatography-tandem mass spectrometry(MS) with electrospray ionization. [(13)C(2),(15)N]Glycine was incorporated into chemically synthesized BK1-5 for use as an internal standard. Blood samples (5 ml) were collected into 15-ml chilled ethanol to prevent artifactual kinin production and degradation. BK1-5 in ethanolic plasma supernatant was purified on a polymeric solid phase extraction cartridge. MS analysis was in the selective reaction monitoring mode. Precision of the assay is +/-7.5% and accuracy is 99%. Recovery of BK1-5 through sample preparation was 43% and the lower limit of detection is 4 fmol/ml blood. Concentrations of BK1-5 in 12 normal volunteers were 44.2 +/- 7.1 fmol/ml blood (mean +/- SE). During blood sampling, no artifactual production of BK1-5 was detected for up to 60 s prior to denaturing the sample. This assay provides the first accurate and precise method using MS to quantify BK1-5 in human blood as a marker for the production of systemic bradykinin in humans.     

Neuropeptide K-(1-24)-peptide: storage and release by carcinoid tumors

An antiserum directed against the COOH-terminal region of neuropeptide K-(1-24)-peptide that shows only 0.5% reactivity with neuropeptide K has been used in radioimmunoassay to study the posttranslation processing of human beta-preprotachykinin. A primary midgut carcinoid tumor contained high concentration of substance P (2970 pmol/g), neurokinin A (3660 pmol/g) and neuropeptide K-(1-24)-peptide (3430 pmol/g) but only a very low concentration (less than 5 pmol/g) of intact neuropeptide K. Neuropeptide K-(1-24)-peptide was also detected in extracts of metastatic tumor tissue from four patients with midgut carcinoid tumors. The amino acid sequence of tumor neuropeptide K-(1-24)-peptide was identical to that predicted from the nucleotide sequence of a human beta-preprotachykinin cDNA. The fasting plasma concentration of neuropeptide K-(1-24)-peptide was elevated in a patient with the carcinoid syndrome (821 fmol/ml compared with less than 18 fmol/ml in healthy subjects) and rose approximately 2-fold after intravenous pentagastrin. The study has demonstrated that the Lys25-Arg26 bond in neuropeptide K (corresponding to Lys96-Arg97 in the precursor) is an important processing site in human beta-preprotachykinin.     

Measurement of T-kinin in rat plasma using a specific radioimmunoassay.

T-kinin (Ile-Ser-Bradykinin) has been isolated only from the plasma of the rat and it is unclear whether the peptide, or its biosynthetic precursor, T-kininogen, circulates in the human. An NH2-terminally directed antiserum to T-kinin was raised in rabbits using an immunogen prepared by coupling the free -SH group of T-kinin extended from its COOH-terminus by a cysteinyl residue to an -NH2 group on human serum albumin. A radioimmunoassay was developed using this antiserum and 125I-labelled [Tyr10]T-kinin as tracer that was sensitive (least-detectable concentration 3 fmol/tube) and relatively specific for T-kinin (cross-reactivity with bradykinin and kallidin less than 1%). Treatment of rat plasma with an excess of trypsin in the presence of a kininase inhibitor generated T-kinin immunoreactivity equivalent to 455 +/- 71 pmol/ml (mean +/- S.E.M.; n = 9) and this immunoreactivity was eluted from a reversed-phase HPLC column as a single peak with the same retention time as synthetic T-kinin. In contrast, treatment of plasma from healthy human subjects (n = 8) and from patients (n = 8) with inflammation due to acute or chronic gastrointestinal disease under the same conditions did not generate any detectable T-kinin immunoreactivity. It is concluded, therefore, that T-kininogen, the biosynthetic precursor of T-kinin in the rat, is either absent from the plasma of human subjects or is present in a concentration less than 30 fmol/ml. Similarly, T-kininogen is probably not an acute phase reactant in humans.     

NH2-terminal fragment of rat pro-atrial natriuretic factor in the circulation: identification, radioimmunoassay and half-life

A radioimmunoassay was developed to measure the NH2-terminal counterpart of rat pro-atrial natriuretic factor (pro-ANF) in plasma. Synthetic rat ANF (Asp 11-Ala 37) coupled to bovine serum albumin was used to immunize New Zealand rabbits. The antiserum demonstrated good immunoreactivity towards rat ANF (Asn 1-Arg 98), (Asn 1-Tyr 126), (Asp 11-Ala 37) and even human ANF (Asn 1-Ser 30). The standard curve had an ED80 of 9.5 +/- 2.5 and ED50 of 44.0 +/- 10.5 fmol/tube. Immunoreactive ANF NH2-terminal peptide was measured directly in rat plasma without prior extraction. In fact, extraction of ANF NH2-terminal from plasma by C18 silica gel chromatography revealed inconsistent recovery and a lack of parallelism. Morphine (0.75 mg/100 g), chosen to elicit increased ANF (Ser 99-Tyr 126) secretion, elevated its plasma concentration from 54.1 +/- 3.2 to 190.8 +/- 55.8 fmol/ml after 20 min. At the same time, the immunoreactive NH2-terminal fragment rose from 378 +/- 16 to 1181 +/- 201 fmol/ml. The identity of this immunoreactive material was verified following affinity chromatography and reverse-phase high-performance liquid chromatography (HPLC) of plasma from morphine-treated rats. Molecular sieving and amino acid sequencing demonstrated that it appears to be consistent with or identical to rat ANF (Asn 1-Arg 98). The disappearance rate of ANF (Asn 1-Arg 98) was studied by injecting radioactive material into anesthetized rats. The exponential decay was analyzed by a two-compartment model in which the fast and slow components had a half-life of 2.5 +/- 0.3 and 54.8 +/- 3.9 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement and partial characterization of the multiple forms of neurokinin A-like immunoreactivity in carcinoid tumours

An antiserum raised against neurokinin A has been used to demonstrate storage and release of neurokinin A-like immunoreactivity by carcinoid tumours. The antiserum showed reactivity towards members of the tachykinin family of polypeptides in the order: neurokinin A greater than eledoisin greater than neurokinin B greater than kassinin greater than substance P greater than physalaemin but the magnitude of the cross-reactivity with substance P and physalaemin was less than 1% of that of neurokinin A. A sensitive (IC50 238 fmol/ml; minimum detectable concentration, 9 fmol/ml) radioimmunoassay was set up using this antiserum. Extracts of metastatic tumour tissue from four patients with a primary carcinoid tumour in the midgut contained both neurokinin A-like immunoreactivity (NKA-LI) and substance P-like immunoreactivity (SP-LI). The concentrations (pmol/g wet weight) of NKA-LI and SP-LI in the tumours were: patient A 210, 201; patient B 2276, 6849; patient C 1198, 834 and patient D 424, 379. Analysis of the tumour extracts by reverse phase HPLC indicated that the NKA-LI was heterogeneous. Under two different conditions of chromatography, one component was eluted with the same retention time as neurokinin A. Two further components were more hydrophobic than neurokinin A but were not eluted with the retention time of neurokinin B. Analysis of these components by gel filtration indicated a molecular weight in the 3000-4000 range suggesting that they may be related to neuropeptide K, an N-terminally extended form of neurokinin A. NKA-LI and SP-LI were undetectable in the plasma of patients A and D but were elevated in patient B (NKA-LI 1005 +/- 114; SP-LI 345 +/- 85 fmol/ml) and patient C (NKA-LI 80 +/- 31; SP-LI 21 +/- 13 fmol/ml).     

Recombinant granulocyte colony-stimulating factor induces production of human neutrophil peptides in lung cancer patients with neutropenia

Human neutrophil peptides (HNPs) 1, 2 and 3 are antimicrobial peptides localized in the azurophil granules of neutrophils. We investigated the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on the biosynthesis of HNPs 1-3 using a sensitive radioimmunoassay and Northern blot analysis. Seven patients with lung cancer were first treated with various anticancer agents for 3 days (days 1-3) followed by treatment with rhG-CSF (2 microgram/kg weight/day) for 7 days (days 8-14). Chemotherapy caused neutropenia but the neutrophil count increased biphasically between days 8 and 14. Chemotherapy did not change the baseline plasma concentration of HNPs 1-3 (74.1+/-2.1 pmol/ml) but the concentration increased from day 12, 5 days after commencement of rhG-CSF therapy, to reach a peak value of 430.8+/-57.0 pmol/ml on day 15, 1 day after the last administration of rhG-CSF. Baseline HNPs 1-3 content per neutrophil was 0.59+/-0.02 fmol, decreased to 0.30+/-0.07 fmol on day 9, then increased to 0.78+/-0.07 fmol on day 15. Analyses of peripheral blood neutrophils by Northern blot and reverse-phase high-performance liquid chromatography showed that the amounts of HNPs 1-3 mRNA and precursors of HNPs 1-3 markedly increased in response to rhG-CSF. Our results indicate that recombinant hG-CSF does not only increase neutrophil count but stimulates HNPs 1-3 biosynthesis in neutrophils, thus enhancing the host defense system of compromised hosts with neutropenia.     

Simultaneous circadian variations of plasma ACTH, beta-lipotropin, beta-endorphin and cortisol

The major objective of this study was to investigate the analogy existing between the typical circadian periodicity of ACTH and that recently described of beta-lipotropin (beta-LPH) and beta-endorphin (beta-EP) plasma levels. The determination of their concentrations, plus cortisol, has been performed on the same plasma samples of 6 healthy volunteers. All hormones were measured by radioimmunoassay. Those of beta-LPH and beta-EP were preceded by a purification of plasma through silicic acid extraction and Sephadex G-75 gel filtration. The highest values (mean +/- SEM) were found in the morning (ACTH: 10.3 +/- 0.9; beta-LPH; 6.3 +/- 0.7; beta-EP: 6.5 +/- 0.5 fmol/ml; cortisol: 378 +/- 30 pmol/ml) and the lowest values in the evening (ACTH: 6:1 +/- 0.7; beta-LPH: 3.3 +/- 0.4; beta-EP: 3.7 +/- 0.6 fmol/ml; cortisol: 130 +/- 23 pmol/ml). Statistical analysis using the Fourier method led to the evidence of a concomitant circadian secretory pattern of the three proopiocortin-related peptides. These results strongly suggest that the phasic secretion of ACTH, beta-LPH and beta-EP underlies a common central control.     

Angiotensin stimulates oxytocin release

A sensitive and specific radioimmunoassay for oxytocin (OT) was developed to study the effect of angiotensin II (ANG II) upon neurohypophyseal OT release in conscious rats. ANG II injected into the lateral cerebral ventricle (i.c.v.) produced within 60 seconds a steep increase in plasma OT concentration from a control value of 10.46 ± 1.35 fmol/ml to 88.95 ± 5.06 fmol/ml and 119.56 ± 11.46 fmol/ml following 10 and 100 ng i.c.v. ANG II, respectively. Inhibition of OT release by simultaneous application of the ANG II antagonist {Sar¹, Ile⁸}-ANG II suggests that ANG II acted via specific angiotensin receptors in the brain.     

Development and validation of a sensitive radioimmunoassay for naturally occurring beta-endorphin-like peptides in human plasma

β-Endorphin-like peptides in blood plasma of normal human subjects were studied by means of a radioimmunoassay (RIA) and gel filtration. Plasma was extracted with silica gel, which was washed with water and 1 n HCl, and eluted with 50% acetone. Plasma extracts thus obtained and standard synthetic human β-endorphin yielded parallel RIA curves. Total immunoreactivity in normal donors ranged from 1.2 to 10.4 fmol/ml (21 subjects). The immunoreactivity was completely destroyed by treatment with papain. Gel filtration indicated the presence of three components-one of unknown nature at the void volume and the others at elution positions characteristic of β-lipotropin and β-endorphin. Recoveries of human β-endorphin and β-lipotropin added to plasma were 53 and 58%, respectively. Addition of N-ethylmaleimide to plasma or of aprotinin to blood immmediately following collection had no effect on the amount of total immunoreactivity. Furthermore, a large amount of β-endorphin-like immunoreactivity. The above results lead us to conclude that a β-endorphin-like immunoreactive peptide occurs naturally in plasma of normal human subjects.     

Changes in the plasma and urine alpha human atrial natriuretic peptide (alpha hANP) concentration in patients with thyroid disorders

In order to assess the possible involvement of thyroid hormone in alpha human atrial natriuretic peptide (alpha hANP), we investigated the plasma and urine ANP concentration in patients with primary hyperthyroidism and hypothyroidism. Plasma and urine were extracted through Sep-Pak C18 cartridges and the urine ANP concentration was corrected by urine creatinine (cre. mg/dl) and expressed as fmol/mg.cre.. The plasma ANP concentration in patients with untreated hyperthyroidism (32.3 +/- 7.0 fmol/ml; n = 22) was higher than in normal subjects (p less than 0.01 vs control; 6.2 +/- 0.7 fmol/ml). After restoration to euthyroidism, the plasma ANP concentration (patients with treated hyperthyroidism) fell to normal (8.9 +/- 1.9 fmol/ml). The plasma ANP concentration in patients with untreated hypothyroidism (14.1 +/- 3.0 fmol/ml; n = 7) was higher than normal, but in two of them there was mild renal dysfunction and an incomplete right blundle branch block in the electrocardiogram. It was possible that these factors contributed to the observed increase in plasma ANP. However, a significant positive correlation was found between plasma ANP and free thyroxine (n = 40, r = 0.449; p less than 0.01) and free triiodothyronine (n = 40, r = 0.546; p less than 0.01). The urine ANP concentration in patients with untreated hyperthyroidism was markedly higher than in normal subjects (p less than 0.01), but in untreated hypothyroidism not significantly different from normal.     

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)     

Angiotensin-(1--7) in the ovine fetus

In the adult animal, ANG-(1-7) may counterbalance some effects of ANG II. Its effects in the fetus are unknown. Basal ANG-(1-7), ANG I, ANG II, and renin concentrations were measured in plasma from ovine fetuses and their mothers (n = 10) at 111 days of gestation. In the fetus, concentrations of ANG I, ANG-(1-7), and ANG II were 86 +/- 21, 13 +/- 2, and 14 +/- 2 fmol/ml, respectively. In the ewe, concentrations of ANG I were significantly lower (20 +/- 4 fmol/ml, P < 0.05) as were concentrations of ANG-(1-7) (2.9 +/- 0.6 fmol/ml), whereas ANG II concentrations were not different (10 +/- 1 fmol/ml). Plasma renin concentrations were higher in the fetus (4.8 +/- 1.1 pmol ANG I x ml(-1) x h(-1)) than in the ewe (0.9 +/- 0.2 pmol x ml(-1) x h(-1), P < 0.05). Infusion of ANG-(1-7) (approximately 9 microg/h) for a 3-day period caused a significant increase in plasma concentrations of ANG-(1-7) reaching a maximum of 448 +/- 146 fmol/ml on day 3 of infusion. Plasma levels of ANG I and II as well as renin were unchanged by the infusion. Urine flow rate, glomerular filtration rate, and fetal arterial blood pressure did not change and were not different than values in fetuses receiving a saline infusion for 3 days (n = 5). However, the osmolality of amniotic and allantoic fluid was significantly higher in fetuses that received ANG-(1-7). Also, compared with the saline-infused animals, mRNA expression levels of renin, the AT(1) receptor, and AT(2) receptor were elevated in kidneys of fetuses that received infusions of ANG-(1-7). Infusion of an ANG-(1-7) antagonist ([D-Ala(7)]-ANG-(1-7), 20 microg/h) for 3 days had no effect on fetal blood pressure or renal function. In conclusion, although infusion of ANG-(1-7) did not affect fetal urine flow rate, glomerular filtration rate, or blood pressure, changes in fetal fluids and gene expression indicate that ANG-(1-7) may play a role in the fetal kidney.