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.

Effects of arginine-vasopressin and parathyroid hormone-related protein (1-34) on cell proliferation and production of YKL-40 in cultured chondrocytes from patients with rheumatoid arthritis and osteoarthritis.

Objective: Both arg-vasopressin (AVP) and parathyroid hormone-related protein (PTHrP) may act as proinflammatory hormones. In addition, they have been suggested to be involved in the pathophysiology of rheumatoid arthritis (RA). We therefore investigated the effects of AVP and PTHrP (1-34) on cell proliferation and secretion of the glycoprotein YKL-40 in human chondrocytes derived from healthy subjects as well as from patients with RA or osteoarthritis (OA).

The effects of arg-vasopressin on osteoblast-like cells in endothelial nitric oxide synthase-knockout mice and their wild type counterparts.

In the present study, we investigated whether nitric oxide (NO) could be involved in the effects of arg-vasopressin (AVP) on osteoblast-like cells. Cells derived from endothelial nitric oxide synthase (eNOS)-knockout mice and their wild type (WT) counterparts, and an osteosarcoma cell line (SaOS-2) were used. AVP (10-100 pmol/l) increased proliferation of osteoblast-like cells from WT mice.

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.

Galanin in human plasma.

The neuropeptide galanin has important effects on hormone secretion from the hypothalamus and pituitary, and it may also be involved in central 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 26 healthy subjects, 14 women and 12 men, using two extraction methods and a specific radioimmunoassay for human galanin.

Inhibited anabolic effect of insulin-like growth factor-I on stromal bone marrow cells in endothelial nitric oxide synthase-knockout mice.

Aims: Insulin-like growth factor-I (IGF-I), parathyroid hormone (PTH) and PTH-related protein (PTHrP) are hormones that have anabolic effects on bone formation. The aim of this study was to investigate whether production of nitric oxide (NO) is involved in the effect of IGF-I and PTH/PTHrP on osteoblast-like cells.

Methods: Bone marrow stromal cells from adult endothelial nitric oxide synthase (eNOS)-knockout (eNOSKO) mice and wild type (WT) counterparts were cultivated with osteogenic substances.

Arg-vasopressin increases proliferation of human osteoblast-like cells and decreases production of interleukin-6 and macrophage colony-stimulating factor.

Patients with arginine-vasopressin (AVP) deficiency have been reported to have a decreased bone mass. The mechanism behind this is not known. In this study, the effects of AVP on primary human osteoblast-like (hOB) cells and SaOS-2 cells were investigated.

Extracellular calcium increases free cytoplasmic calcium and DNA synthesis in human osteoblasts.

A high concentration of extracellular calcium (8 mM) induced an increase in free cytoplasmic calcium, a lower cyclic AMP level and increased DNA synthesis in primary cultures of human osteoblast-like cells. Inhibition of protein kinase C with bisindolylmaleimide I inhibited the stimulatory effect of extracellular calcium on DNA synthesis in human osteoblast-like cells, whereas inhibition of protein kinase A with Rp-cAMPs had no effect on DNA synthesis. This indicates that protein kinase C, possibly via increased free cytoplasmic calcium, mediates the effect of extracellular calcium on DNA synthesis in osteoblast-like cells rather than a relative decrease in cyclic AMP and protein kinase A activity.

Weak evidence of thyrotropin receptors in primary cultures of human osteoblast-like cells.

Extra-thyroidal thyrotropin (TSH) receptors (TSHRs) have been demonstrated in several tissues and cells, including human and rat osteosarcoma cell lines. We have explored whether human TSHR (hTSHRs) also are present in primary cultures of human osteoblast-like (hOB) cells. [(125) I]TSH binding was limited in hOB cells, but somewhat higher in UMR 106-01 cells and considerably higher in hTSHR-transfected CHO cells.

ATP dependent Ca2+ transport across basal membrane of human syncytiotrophoblast in pregnancies complicated by intrauterine growth restriction or diabetes.

Neonates born after pregnancies complicated by diabetes or intrauterine growth restriction (IUGR) have increased incidence of hypocalcaemia. Furthermore, IUGR is associated with reduced bone mineralization in infancy and osteoporosis in adult life. We tested the hypothesis that placental calcium transport is altered in these pregnancy complications.

Cobalt ions influence proliferation and function of human osteoblast-like cells.

Cobalt is the major component in many orthopedic implants and the introduction of a second generation of metal on metal bearing prosthesis systems actualizes the toxicity and biocompatibility of this compound. We studied the effect of cobalt ions on primary cultures of human osteoblast-like cells. Cobalt ions dissolved in cell culture medium caused a dose-dependent decrease in proliferation of human osteoblasts measured as (3H)thymidine incorporation.

Oxytocin stimulates proliferation of human osteoblast-like cells.

Oxytocin receptors have recently been demonstrated in human osteoblast-like (hOB) cells. In this study, oxytocin 100-1000 pmol/l increased cell proliferation of primary cultures of hOB cells, measured by [3H]thymidine incorporation, (P<0.01).

Synovial fluid from loose hip arthroplasties inhibits human osteoblasts.

Aseptic loosening of prosthetic components in patients who have undergone total hip arthroplasty is a major clinical problem. Earlier studies on this topic have focused mainly on different aspects of bone resorption. The current study investigated the influence of synovial fluid from patients who underwent revision surgery because of aseptic loosening and synovial fluid from patients with osteoarthritis on the proliferation of primary cultures of human osteoblasts.

Interleukin-1beta upregulates PTHrP-mRNA expression and protein production and decreases TGF-beta in normal human osteoblast-like cells.

Osteoblasts are regulated by complex interactions among systemic hormones, cytokines, and local growth factors. Bone resorption, at the level of the basic multicellular unit, is initiated by stimulation of osteoblast activity. The stimulatory effect of interleukin-1beta (IL-1beta) on bone resorption has not been fully clarified.

Calcitonin-suppressed expression of parathyroid hormone-related protein in breast cancer cells.

Parathyroid hormone-related protein (PTHrP) is a key factor behind humoral hypercalcemia of malignancy (HHM). It is produced in most breast tumors and may be an important local mediator of skeletal metastases due to breast cancer. PTHrP may mediate local bone destruction in the absence of increased circulating PTHrP.

Two human osteoblast-like osteosarcoma cell lines show distinct expression and differential regulation of parathyroid hormone-related protein.

Parathyroid hormone (PTH)-related protein (PTHrP) acts as a local regulator of osteoblast function via mechanisms that involve PTH/PTHrP receptors linked to protein kinase A (PKA) and C (PKC). However, the regulation of PTHrP production and mRNA expression in human osteoblasts is poorly understood. Here we have characterized alternative PTHrP mRNA 3' splicing variants, encoding PTHrP isoforms of 139, 141, and 173 amino acids, and studied the regulation of PTHrP and its mRNAs by activated PKA and PKC in two human osteoblast-like cell lines (KPDXM and TPXM).

Parathyroid hormone-related protein in patients with primary breast cancer and eucalcemia.

Parathyroid hormone-related protein (PTHrP) is a causative factor of humoral hypercalcemia in breast cancer and other malignancies. We studied circulating PTHrP levels with three different immunoassays directed against different parts of the PTHrP molecule in 48 patients with breast cancer and eucalcemia. The methods used were: (a) a RIA with antibodies directed toward the midregion (63-78); (b) an immunofluorometric assay with two antibodies against 1-34 and 38-67; and (c) an immunoradiometric assay with antibodies against 1-40 and 1-72.

Parathyroid hormone-related protein (1-37) induces cAMP response in human osteoblast-like cells.

During recent years parathyroid hormone-related protein (PTHrP) research has been focused on the physiological functions of different fragments of the PTHrP molecule. Here we demonstrate that PTHrP (1-37) induced cyclic adenosine monophosphate (cAMP) response in primary human osteoblast-like cells, which were well characterized by the presence of alkaline phosphatase activity and osteocalcin production after stimulation with 1,25-dihydroxyvitamin D3. However, there was no cAMP response to PTHrP (58-77).

Quantification of parathyroid hormone-related protein mRNA by competitive PCR and time-resolved lanthanide fluorometry.

Using dissociation and enhancement time-resolved lanthanide fluorometry, we have developed a quantitative competitive (QC)-PCR for measuring parathyroid hormone-related protein (PTHrP) mRNA after reverse transcription. A cloned PTHrP cDNA target was also modified by deletion of 10 bp and insertion of 21 bp in the midregion of the fragment and cloned for use as a competitor (i.e.

Effect of acute endurance and strength exercise on circulating calcium-regulating hormones and bone markers in young healthy males.

Physical activity plays a role in the maintenance of the skeleton but the mechanical, metabolic and hormonal mechanisms involved are largely unknown. The influence of acute endurance and strength exercise on circulating levels of calcitonin, parathyroid hormone (PTH), PTH-related peptide (PTHrP), osteocalcin, carboxyterminal cross-linked telopeptide of type I collagen (ICTP) and ionized calcium (Ca2+) was therefore evaluated. Eight healthy young males performed three exercise bouts on separate occasions: endurance exercise, i.

Parathyroid hormone-related protein in neonatal and reproductive goats determined by a sensitive time-resolved immunofluorometric assay.

Objective: High concentrations of parathyroid hormone-related protein (PTHrP) have been found in goat milk but it is not known whether it can enter the circulation of the neonate. In this study we have developed a sensitive two-site lanthanide immunofluorometric assay (IFMA) using dissociation and enhancement time-resolved fluorometry to address this question.

Method: Affinity-purified anti-PTHrP 38-67 raised in rabbit was biotinylated and immobilized in streptavidin-coated microtitration wells as a 'capture' antibody.

Two-site immunofluorometric assay of intact salmon calcitonin with improved sensitivity.

We recently developed a two-site immunofluorometric assay (IFMA) of salmon calcitonin (SCT) by DELFIA (dissociation enhancement lanthanide fluoroimmunoassay) technique using the same polyclonal antibodies both for "catching" the antigen and for signaling. In the present study we used a monoclonal antibody to SCT 1-11 as the capture antibody. This antibody was biotinylated before use in streptavidin-coated microtitration plates.

Estimation of the C-cell numbers in rat thyroid glands using the optical fractionator.

We estimated the total number of calcitonin-immunoreactive C-cells in rat thyroid gland using the optical fractionator, the unbiased stereological method for estimation of numbers. It was necessary first to use a fixative composed of formalin, acetic acid, and ethanol to distinctly visualize the C-cells. The 40-microm-thick sections had to adhere to chromalum-gelatin-coated Superfrost Plus glass slides, and the immunostaining technique had to stain the C-cells evenly throughout the whole sections.

Circulating monomer-like calcitonin in osteoporotic patients.

Physiological concentrations of monomeric calcitonin can inhibit osteoclastic bone resorption in vitro. We therefore investigated the circulating molecular forms, including monomer-like calcitonin, and their concentrations in 9 men and 9 women with established osteoporosis. Calcitonin was immunoextracted from serum by the use of rabbit calcitonin antibodies coupled to Sepharose 4B.

Midmolecular parathyroid hormone-related peptide in serum during pregnancy, lactation and in umbilical cord blood.

Indications of an important physiological role of parathyroid hormone-related peptide (PTHrP) for fetal calcium homeostasis, maternal-fetal calcium transport and reproduction have accumulated over recent years. The PTHrP concentrations were measured by an earlier developed midregion radio-immunoassay in serum from lactating healthy females and umbilical cord blood and compared with levels in age-matched non-pregnant or lactating females. The PTHrP concentrations could be measured in all samples after silica cartridge C18 extraction of 10-12 ml of serum.