An enzymatic solid-phase method for trace iodination of proteins and peptides with 125iodine

Karonen, Sirkka-Liisa; Mörsky, Pertti; Sirén, Marita; Seuderling, U.

doi:10.1016/0003-2697(75)90266-3

Cited by 130 publications

(27 citation statements)

References 17 publications

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“…Highly purified human chorionic gonadotropin (hCG; NIH CR-121; 11500 IU/mg; National Institutes of Health) was iodinated with Na-[ 125 I]iodide (Amersham International plc) using a solid-phase lactoperoxidase method to a specific activity of about 20 Ci/g (24). LH radioreceptor assay was performed according to the method of Catt et al (25).…”

Section: Methodsmentioning

confidence: 99%

Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex

Kero¹,

Poutanen²,

Zhang³

et al. 2000

J. Clin. Invest.

142

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Transgenic (TG) female mice expressing bLHβ-CTP (a chimeric protein derived from the β-subunit of bovine luteinizing hormone [LH] and a fragment of the β-subunit of human chorionic gonadotropin [hCG]) exhibit elevated serum LH, infertility, polycystic ovaries, and ovarian tumors. In humans, increased LH secretion also occurs in infertility and polycystic ovarian syndrome, often concomitant with adrenocortical dysfunction. We therefore investigated adrenal function in LH overexpressing bLHβ-CTP female mice. The size of their adrenals was increased by 80% with histological signs of cortical stimulation. Furthermore, adrenal steroid production was increased, with up to 14-fold elevated serum corticosterone. Primary adrenal cells from TG and control females responded similarly to ACTH stimulation, but, surprisingly, the TG adrenals responded to hCG with significantly increased cAMP, progesterone, and corticosterone production. LH receptor (LHR) expression and activity were also elevated in adrenals from female TG mice, but gonadectomized TG females showed no increase in corticosterone, suggesting that the dysfunctional ovaries of the intact TG females promote adrenocortical hyperfunction. We suggest that, in intact TG females, enhanced ovarian estrogen synthesis causes increased secretion of prolactin (PRL), which elevates LHR expression. Chronically elevated serum LH, augmented by enhanced PRL production, induces functional LHR expression in mouse adrenal cortex, leading to elevated, LH-dependent, corticosterone production. Thus, besides polycystic ovaries, the bLHβ-CTP mice provide a useful model for studying human disorders related to elevated LH secretion and adrenocortical hyperfunction.

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Section: Methodsmentioning

confidence: 99%

Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex

Kero¹,

Poutanen²,

Zhang³

et al. 2000

J. Clin. Invest.

142

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“…Beef and pork proinsulins (provided by Nov 9 Laboratories Ltd.) were labelled with 125I by means of solid-phase lactoperoxidase [3] and purified on cellulose columns (Whatman CF11) [4]. In the determination of proinsulin binding insulin-binding antibody was blocked by including highly purified pork insulin in the incubation buffer at a concentration of 6.7 U/ml [5].…”

Section: Assay Methodsmentioning

confidence: 99%

Decrease of antibodies to insulin, proinsulin and contaminating hormones after changing treatment from conventional beef to purified pork insulin

et al. 1980

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Summary. The sera of 30 patients who had been treated with conventional beef insulin were tested for binding of insulin and other pancreatic hormones. All showed antibody binding of insulin, 29 binding of proinsulin, 29 binding of pancreatic polypeptide, two binding of glucagon but none of the sera bound vasoactive intestinal peptide or somatostatin. After changing therapy to highly purified pork insulin the binding capacity of sera for insulin and the other hormones was monitored for up to 35 months and a steady fall was found in nearly all cases. In eight of the patients conventional beef insulin treatment was resumed: in one month binding of insulin and of the other hormones increased back to the initial levels. In eighteen subjects who had only received highly purified pork insulin low levels of insulin binding were found with no binding of proinsulin or other hormones. The amounts of proinsulin and contaminating hormones in highly purified pork insulin are so low that they are not immunogenic; conventional beef insulin not only contains immunogenic amounts of proinsulin and the contaminating hormones pancreatic polypeptide and glucagon but also is more immunogenic than purified pork insulin.Key words: Insulin, proinsulin, pancreatic polypeptide, glucagon, antibodies.Conventional beef insulin preparations are more immunogenic than highly purified pork insulin [1]. They contain appreciable quantities of proinsulin, pancreatic polypeptide (PP), glucagon, somatostatin and vasoactive intestinal peptide (VIP) [2]. The greater immunogenicity of the conventional beef insulins has been attributed to the contaminants although other factors such as alteration or polymerisation of the insulin may be more important. A change of therapy from beef to purified pork insulin involves both a change in the species of insulin origin and an increase in purity as well as a possible change in the physical or chemical state of the insulin.In the present study the antibodies to insulin, proinsulin, PP, glucagon, somatostatin and VIP have been measured in patients treated with conventional beef insulin before and at intervals after a change to highly purified pork insulin. Materials and Methods PatientsThirty insulin treated patients were studied; 17 males and 13 females with an average age at the start of the study of 33 years (range 12-67) and an average duration of diabetes of 12 years (range 5-38).For at least six months before the start of this study all the patients were treated with twice daily soluble and isophane beef insulin with an average daily dose of 55 U (range 24-84): before this some had received other beef insulin preparations including beef/pork mixtures. None of the patients were regarded as "britfie" or insulin resistant, their antibody status was not known when they entered this study and none were taking immunosuppressive drugs or steroids.An initial blood sample was collected and then, after changeover to highly purified pork insulin (twice daily Leo Neutral | and Leo Retard | insulins), blood samples were col...

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“…Human transferrin was conjugated with 1251 by means of lactoperoxidase either in liquid (14) or solid phase (15). The initial step involved saturation of transferrin with iron, to prevent iodination of iron binding sites and to reduce the risk of radiation-induced ' Abbreviations used in this paper: PBS, phosphatebuffered saline; PHA, phytohemagglutinin; 125I-Trf, radioiodinated transferrin (1251).…”

Section: Methodsmentioning

confidence: 99%

Transferrin Binding to Peripheral Blood Lymphocytes Activated by Phytohemagglutinin Involves a Specific Receptor

Galbraith¹,

Werner²,

Arnaúd³

et al. 1980

J. Clin. Invest.

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An enzymatic solid-phase method for trace iodination of proteins and peptides with 125iodine

Cited by 130 publications

References 17 publications

Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex

Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex

Decrease of antibodies to insulin, proinsulin and contaminating hormones after changing treatment from conventional beef to purified pork insulin

Transferrin Binding to Peripheral Blood Lymphocytes Activated by Phytohemagglutinin Involves a Specific Receptor

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