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W H Daughaday

Publications and source records attributed to W H Daughaday.

At least 19 recordsLinked to original sources
PubMed1992

Retinoic acid regulates insulin-like growth factor II expression in a neuroblastoma cell line.

Insulin-like growth factors (IGF-I and IGF-II) are mitogenic polypeptides that play an important role in normal growth and development. IGF-II has been shown to stimulate the growth of neuroblastoma tumors in an autocrine and paracrine fashion. Critical in determining the role of IGF-II in tumorigenesis is the necessity to delineate factors affecting the transcription of IGF-II in normal and tumor tissues. To date such factors are poorly characterized. In this study we find that retinoic acid (RA), a naturally occurring morphogen, that has been shown to be indispensable in the development of the chick limb bud, stimulates an increase in IGF-II messenger RNA (mRNA) in the Lan-1-15N neuroblastoma cell line. This increase in IGF-II is coincident with RA mediated inhibition of DNA synthesis. An increase in the steady state levels of IGF-II mRNA is detectable within 2 h of RA treatment and maximal by 24 h. In RA-treated Lan-1-15N cells, IGF-II mRNA levels are regulated at the level of new gene transcription and result in an increase in IGF-II protein in the culture supernatant. These studies suggest one mechanism affecting the production of IGF-II in vivo may be mediated by RA and detail a model system by which transcriptional regulation of IGF-II mRNA can be analyzed.

Cell Division↗
PubMed1992

Measurement of derivatives of proinsulin-like growth factor-II in serum by a radioimmunoassay directed against the E-domain in normal subjects and patients with nonislet cell tumor hypoglycemia.

We describe a modified RIA using a rabbit polyclonal antiserum directed against the first 21 amino acids of the E-domain (E-21) of proinsulin-like growth factor-II (pro-IGF-II). For standardization, we purified big IGF-II from patients with nonislet cell tumor hypoglycemia (NICTH). Under the conditions of our assay there was no significant interference from IGF-binding proteins. The big IGF-II present in the serum of a patient with NICTH displaced [125I]E-(1-21) from antibody parallel to our big IGF-II standard. We found a progressive rise in E-21 immunoactivity (IA) during childhood, with somewhat higher values in girls than in boys. In normal adults the mean E-21 IA level was 138 +/- 49 (+/- SD) micrograms/L. Women with twin pregnancies had higher E-21 IA than women with single pregnancies (302 +/- 66 compared with 120 +/- 18 micrograms/L). We found a marked elevation of E-21 IA in patients with NICTH due to sarcomas (n = 3), hepatoma (n = 2), adrenal carcinoma (n = 1), and carcinoma of the lung (n = 1). No elevation of E-21 IA was present in the serum of a hypoglycemic patient with a hypernephroma or another patient with carcinoma of the lung. Marked elevation of E-21 IA was observed in the serum of patients with renal failure receiving chronic hemodialysis. We conclude that this assay will prove useful in the diagnosis of NICTH in patients who are not azotemic and the investigation of the role of the kidney in clearing products of pro-IGF-II processing.

Adolescent↗
PubMed1992

Heterogeneity of serum peptides with immunoactivity detected by a radioimmunoassay for proinsulin-like growth factor-II E domain: description of a free E domain peptide in serum.

We have reported that normal human sera contain immunoactivity (IA) detected by a RIA directed against the first 21 amino acids of the E domain of proinsulin-like growth factor-II (pro-IGF-II). Marked elevations of E-21 IA were found in the serum of patients with nonislet cell hypoglycemia (NICTH) and patients with renal failure receiving chronic hemodialysis. In this paper we describe some of the properties of the E-21 IA of normal and abnormal sera. The E-21 IA eluted from a calibrated acid Sephadex G-50 column as two major peaks. In normal serum the first major peak had a mol wt (Mr) between 14,000-15,000, and the second peak had a Mr between 5,000-6,000. When E-21 IA from serum of a patient with NICTH was similarly studied, most of the IA was present as a Mr 11,000 peak and only a small amount was present as a 5,000-6,000 Mr peak. In contrast, most of the E-21 IA present in the sera of patients on hemodialysis was present in the smaller molecular form, which eluted from a reverse phase column as a single component. This small Mr peak lacked determinants for the IGF-II monoclonal antibody (Amano), for pooled serum IGF-binding proteins, and for the IGF-I receptors on human placental membranes. We suggest that the 15- and 11-kilodalton peaks represent the glycated and unglycated forms of pro-IGF-II (E-21) reported by others. The glycated form appears to predominate in normal serum, whereas the nonglycated form predominates in the serum of patients with NICTH and renal failure. The 5,000-6,000 Mr E-21 IA probably represents a fragment of the free E domain of pro-IGF-II. Its size is consistent with cleavage of the free E domain between Arg46 and Arg47. The accumulation of this E-21 IA in renal failure is evidence that the kidney has a major role in the clearance of this fragment, which is not accomplished by the membranes used in hemodialysis.

Aged↗
PubMed1992

Pituitary gigantism.

Pituitary gigantism is a rare condition whose association with McCune-Albright syndrome suggests that mutations in alpha-subunit of a Gs protein are an important cause of this condition. In addition to somatotroph adenoma, it is now recognized that somatotroph hyperplasia can also result from increased levels of growth hormone-releasing hormone. Transgenic rats with hypersomatotrophism are prone to renal and hepatic pathology.

Adenoma↗
PubMed1991

Endogenous insulin-like growth factor (IGF) binding proteins cause IGF-1 resistance in cultured fibroblasts from a patient with short stature.

The ED50 of insulin-like growth factor (IGF)-I-stimulated alpha-aminoisobutyric acid (AIB) uptake (mean +/- SD) in cultured fibroblasts from a child with short stature that we have reported (1.40 +/- 0.24 nM), is significantly higher than the ED50 of IGF-I-stimulated AIB uptake in fibroblasts from 11 normal subjects (0.42 +/- 0.12 nM) and from 127 short children (0.35 +/- 0.11 nM). Similarly, the ED50 of IGF-I-stimulated thymidine incorporation in fibroblasts from this child is 2.8 times higher than that in fibroblasts from four normal subjects. To minimize potential modulation of IGF-I action by endogenous IGF binding proteins in these assays, fibroblast responsiveness to [Q3,A4,Y15,L16]IGF-I, an IGF-I variant that has a 600-fold reduced affinity for serum IGF binding proteins, has been examined. The biological activity of this variant is comparable in the patient's and normal fibroblasts, suggesting that the resistance to IGF-I action cannot be attributed to a defective IGF-I receptor. To investigate directly the possibility that IGF-I sensitivity in the patient's fibroblasts is reduced by endogenous IGF binding proteins (IGFBP), binding proteins that are secreted into AIB assay buffer during a 3-h collection and that are cell-associated at the end of the collection have been analyzed. Ligand blot analysis of conditioned AIB assay buffer demonstrates that fibroblasts from the patient secrete 1.3-2.2 times more of Mr 46,400/42,900, 32,000, and 26,800 binding proteins than normal fibroblasts. The major difference between fibroblasts from the patient and from normal subjects is a striking 10-fold increase in the amount of a cell surface Mr 32,000 binding protein in the patient's fibroblasts. The Mr 32,000 binding protein is similar in size to IGFB-1 and different from IGFBP-2 and IGFBP-3, but it does not cross-react with an antibody against IGFBP-1. We conclude that the resistance to IGF-I action in the patient's fibroblasts is caused by an abnormal production and/or cell association of IGF binding proteins.

Aminoisobutyric Acids↗
PubMed1991

Impaired formation of the ternary insulin-like growth factor-binding protein complex in patients with hypoglycemia due to nonislet cell tumors.

In some subjects with hypoglycemia associated with tumors of mesenchymal origin, high insulin-like growth factor-II (IGF-II) levels have been described in serum and in the tumors. Tumor IGF-II of 10-15 kDa circulates in a 60-kDa complex, in contrast to the ternary 150-kDa complex in which serum IGFs normally circulate together with the IGF-binding subunit (IGFBP-3) and the acid-labile subunit (alpha-subunit). This study examines the molecular distribution and complex-forming activity of the components of the ternary complex in the serum of subjects with mesenchymal tumor hypoglycemia. Total serum IGFBP-3 levels were 60% of normal in tumor patients and appeared at 60 kDa on gel chromatography, shifting after tumor removal to 150 kDa. Total alpha-subunit levels were 40% of normal in patients with tumors, increasing after tumor removal to 70% of normal and changing in elution profile from a peak typical of uncomplexed alpha-subunit to the normal broad peak representing both complexed and uncomplexed alpha-subunit. Although low by RIA, alpha-subunit activity in a ternary complex formation assay was normal, indicating that the ability of free alpha-subunit in the patients' circulation to combine with exogenous IGFBP-3 plus IGF-I was not impaired. In contrast, in an assay that tested the ability of IGF-IGFBP complexes in the patients' circulation to combine with pure alpha-subunit, complex formation activity was 75-85% below normal in preoperative sera, despite low normal IGFBP-3 levels. Therefore, the cause of hypoglycemia in these patients may be the inability of complexes between the abnormal tumor IGF-II and IGFBP-3 to be sequestered in the biologically inactive ternary complex.

Aged↗
PubMed1991

Tumor secretion of growth factors.

An increasing number of polypeptide growth factors have been identified that regulate not only cell proliferation but also an extraordinary range of cell activities, including matrix protein deposition and resolution, the maintenance of cell viability, cell differentiation, inflammation, and tissue repair. Normal cells appear to require growth factors for proliferation and for maintenance of viability. Cells that secrete a polypeptide growth factor have an advantage in growth. These factors can act either externally through cell surface receptors or internally during the transport of receptors and growth factors through the endoplasmic reticulum and Golgi apparatus, causing autocrine stimulation of cell growth. Depending on the cell type, growth factors can also be potent inhibitors of cell growth rather than stimulators of growth, and the effect can depend on the presence or absence of growth factors. Among the growth factors considered, IGFs are unusual in that they function both as endocrine and as autocrine/paracrine agents. IGF-II, which is associated with fetal growth, is the IGF most frequently expressed by tumors. There is now convincing evidence that some tumors secrete sufficient IGF-II to have systemic endocrine effects as recognized as nonislet cell tumor hypoglycemia. PDGF is normally highly concentrated in platelets and has major significance in stimulation of cellular proliferation in inflammation and wound repair. Normally, this proliferation is self-limited, but the secretion of PDGF by tumors and its effects on cell proliferation of tumors persist. The fact that PDGF B monomer has an identical structure with that of the proto-oncogene C-cis further strengthens the connection between PDGF and tumor growth. EGF has a restricted role in normal physiology, but its close relative, TGF-alpha, is widely distributed in normal and neoplastic tissues. The common receptor for EGF and TGF-alpha is present in many normal and neoplastic cell types. The EGF receptor is the product of the C-erb gene. The oncogene V-cis is a truncated form of the EGF receptor whose tyrosine kinase activity is not dependent on ligand binding. TGF-beta exists in multiple forms. Although it can transform the morphology of certain cell lines in culture, it probably does not act generally as a mitogenic agent. Its major physiologic role in the body appears to be the stimulation of mesenchymal matrix formation. It is of special importance in the regulation of bone matrix formation. Its expression is increased in many tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Carrier Proteins↗
PubMed1991

Clinical aspects of GH binding proteins.

The high affinity specific binding of 125I-hGH in human serum is attributable to the GH binding protein, which is derived from the extracellular domain of the receptor. Most measurements have been made by gel filtration methods and expressed with a normal human reference serum (RSGHB). The RSGHB is virtually unmeasurable in the cord sera of premature infants and is higher in cord serum of term infants. RSGHB rises progressively in childhood and reaches adult levels after age 20 years. GH deficiency or excess exerts little effect on RSGHB. RSGHB in GH resistance of the Laron-type is virtually undetectable and such measurements are confirmatory of the diagnosis. In African pygmies, the RSGHB fails to rise in late childhood and correlates with decreased IGF-I concentrations and reduced growth velocity at that time. Studies of abnormalities of the GH-BP in nutritional and other medical conditions are in their infancy, but will be greatly aided by simpler assay methods.

Aging↗
PubMed1990

Whole body nitrogen kinetics and their relationship to growth in short children treated with recombinant human growth hormone.

We studied the effects of growth hormone on retention of 15N-labeled amino acids in 34 short, prepubertal, growth hormone-sufficient children and three growth hormone-deficient subjects. All 34 non-growth hormone-deficient children had apparently normal circulating growth hormone molecules and no mutations were detected in the growth hormone or IGF-I genes of any subjects. Fibroblasts from 34 children responded normally when challenged with recombinant human IGF-I. During the last 72 h of a 4-d challenge with recombinant human growth hormone (16 micrograms/kg body wt), retention of a mixed 15N-amino acid dose varied between 5.7 and 50.5%. Whole body protein synthesis, breakdown, and net anabolism calculated from the 15N kinetics were all increased by the acute growth hormone challenge. However, no routine clinical feature or laboratory determination correlated with the nitrogen retention response. After subsequent treatment (75 micrograms/kg three times a week) with recombinant human growth hormone for 1 y, there was a significant increase in height velocity, but this increase was not related significantly to pretreatment variables other than inversely to pretreatment height velocity. There was a significant (p = 0.03) correlation between the change in height velocity Z score and the degree of nitrogen retention to acute challenge with growth hormone, but this correlation was too weak (r = 0.37) to be of practical value in predicting the treatment growth response in an individual child.

Adolescent↗
PubMed1990

Hypersomatotropism in pregnant women, as measured by a human liver radioreceptor assay.

Radioreceptor assays (RRAs) provide useful information about the bioactivity of peptide hormones. We have developed a RRA for human GH using membranes prepared from human liver. The assay has 1% cross-reactivity with human PRL, 0.11% cross-reactivity with human chorionic somatomammotropin, and negligible cross-reactivity with bovine and rat GH. The assay has distinct advantages over the IM-9 lymphocyte RRA in having reduced nonspecific interference from serum proteins and providing a uniform source of receptors which can be stored for long periods at -70 C. The coefficient of variation of the assay is 13%. In studies of 55 sera from short children with normal or elevated serum GH concentrations the mean ratio of RRA GH to immunoradiometric assayed GH was 1.28. This assay provided important information about the total GH activity in pregnancy. There was a progressive rise in RRA GH during pregnancy, reaching 64.7 +/- 2.5 (+/- SE) micrograms/L at term. This level is 2-3 times higher than suggested by earlier estimates made with monoclonal antibody RIAs for pituitary GH. At term the contributions to total GH activity of serum are less than 3% from the pituitary, 12% from human chorionic somatomammotropin reacting with the GH receptor, and 85% from placental GH. Despite this great increase in receptor-reactive GH, somatomedin activity by bioassay is reduced, and IGF-I, determined by RIA after acid-gel filtration, is minimally elevated.

Adult↗
PubMed1990

Abnormal processing of pro-IGF-II in patients with hepatoma and in some hepatitis B virus antibody-positive asymptomatic individuals.

Hepatomas are a common malignancy in countries with a high prevalence of hepatitis B virus infections. These tumors may present with severe persistent hypoglycemia. We have studied the possible relationship of production of insulin-like growth factor II (IGF-II) by these tumors and the development of hypoglycemia. Mean IGF-II concentration was not significantly higher in 23 patients with hypoglycemia than in nine patients with euglycemia (542 +/- 61 [SE] micrograms/L vs 382 +/- 52 micrograms/L). Serum IGF-I was more suppressed in patients with hypoglycemia (16 +/- 3 micrograms/L) than in patients with euglycemia (57 +/- 18 micrograms/L). Because an increased percentage of IGF-II in serum of patients with hypoglycemia who have other tumors is present as partially processed pro-IGF-II ("big" IGF-II), we passed sera of patients with hypoglycemia and patients with euglycemia with hepatomas through acidic Bio-Gel P-60 columns. We found that 57% +/- 4.6% of the IGF-II in sera from patients with hypoglycemia was present as big IGF-II compared with 22% +/- 3% in patients with euglycemia with hepatomas (not significantly different from that in normal controls). Four of 11 apparently healthy control subjects who were hepatitis B virus positive also had increased percentages of big IGF-II, suggesting that abnormal processing of pro-IGF-II may result from subtle changes in liver function with this infection. It remains to be determined whether these subjects with increased big IGF-II are at increased risk for the development of hepatomas. In conclusion, we have confirmed marked suppression of IGF-I in the sera of patients with hepatoma and hypoglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Insulin-like growth factor II acts as an autocrine growth and motility factor in human rhabdomyosarcoma tumors.

Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood and appears to arise from developing striated muscle-forming cells. Since insulin-like growth factor II (IGF-II) is involved in normal muscle growth and maturation and elevated IGF-II mRNA levels have previously been reported in rhabdomyosarcomas, we have been studying the possible role of IGF-II in the unregulated growth and invasive potential of these embryonal tumors. In this study, we demonstrate that 13 of 14 rhabdomyosarcoma tumors express high levels of IGF-II mRNA relative to normal adult muscle and also express mRNA for the type I IGF receptors on their cell surface, the receptor thought to mediate the effects of IGF-II on muscle cells. We have established several rhabdomyosarcoma cell lines in mitogen-free media and demonstrate that these cells express type I IGF receptors on their cell surface and secrete IGF-II into the media. Exogenous IGF-II is able to stimulate cellular motility in these cell lines as assayed in a modified Boyden chamber. Finally, alpha IR-3, a type I receptor antagonist, inhibits the growth of these cell lines in serum-free media but does not inhibit IGF-II-induced motility of these cells. These data suggest that endogenously produced IGF-II functions as an autocrine growth and motility factor in many rhabdomyosarcoma tumors. The mitogenic actions of IGF-II are mediated through a domain of the type I IGF receptor that is blocked by alpha IR-3. IGF-II-induced motility may be mediated through an alternative signaling pathway.

Cell Division↗