The incorporation of tritium-labelled amino acids into insulins in rat pancreas <i>in vitro</i>

Mallory, Andrew; Smith, G. Howard; Taylor, K. W.

doi:10.1042/bj0910484

Cited by 30 publications

(13 citation statements)

References 18 publications

(12 reference statements)

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“…DISCUSSION Extraction procedure. A serious difficulty in studies of insulin biosynthesis in mammalian pancreas has been the isolation of labelled insulin in a state of radiochemical purity (Mallory et al 1964;Humbel, 1965). The use of immunological techniques, based on the direct precipitation of insulin by antibody, to purify insulin has been described in detail .…”

Section: Resultsmentioning

confidence: 99%

“…The combined solutions were then applied to paper for further purification by two-dimensional chromatography and electrophoresis. The distribution of radioactivity along the strip was determined by methods that have already been described (Mallory et al 1964). Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The use of isolated pancreas slices in vitro for the study of the synthesis and secretion of insulin has already been described (Mallory, Smith & Taylor, 1964;Coore & Randle, 1964), and it seems that this preparation may serve as a physiological model for islet-cell function in vivo. Islet tissue incubated in vitro has a normal appearance on electron microscopy (see Williamson, Lacy & Taylor, 1967).…”

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confidence: 99%

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The secretion of newly synthesized insulin in vitro

Howell¹,

Taylor²

1967

Biochemical Journal

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1. An immunological method for the purification of small quantities of insulin has been devised. 2. This method has been used to isolate labelled insulin secreted from pancreas slices incubated in vitro. The insulin had previously been labelled by incubation of the slices with [(3)H]leucine in vitro. 3. There is some release of labelled insulin when such slices are further incubated in media of low glucose content. When the glucose content of the medium is raised, little additional radioactive insulin is released in the first hour after labelling. However, there is a marked increase in specific radioactivity of insulin released from slices in response to a high concentration of glucose in the second and third hours. Release of labelled insulin is again diminished in the final phase, 4hr. from the start of the experiment. 4. These results are discussed in relation to possible mechanisms of insulin release from the beta-cell.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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The secretion of newly synthesized insulin in vitro

Howell¹,

Taylor²

1967

Biochemical Journal

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“…Because of the known affinity of amino acids of high specific activity for polypeptides (8) we were concerned that phenylalanine-3H had been carried through the isolation procedure associated with vasopressin. This concern was supported by an experiment in which phenylalanine-8H was mixed with unlabeled AVP, oxidized with performic acid, and chromatographed on DEAE Sephadex with the gradient elution described above.…”

Section: Incubation and Isolation Of Avp From Tumormentioning

confidence: 99%

Biosynthesis of Vasopressin In Vitro and Ultrastructure of a Bronchogenic Carcinoma

George¹,

Capen²,

Phillips³

1972

J. Clin. Invest.

119

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A B S T R A C T Tumors from patients with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) have been found to contain large amounts of the antidiuretic hormone vasopressin. A lung tumor from a patient with hyponatremia most likely due to SIADH was removed at surgery and found to contain 23.5 mU vasopressin/g wet weight by radioimmunoassay Slices of this tumor were incubated with phenylalanine-3H. Arginine vasopressin-H was purified from the incubate by Sephadex G-25 column chromatography in two different systems, performic acid oxidation, and gradient elution column chromatography with diethylaminoethyl Sephadex. As oxidation of vasopressin results in drastic conformational change with breaking of the ring of the cyclic polypeptide and addition of two cysteic acid residues per molecule, the radioactive material which eluted coincident with vasopressin both before and after this procedure was considered to be arginine vasopressin-'H. To our knowledge this is the first demonstration of in vitro biosynthesis of vasopressin by a tumor from a patient with SIADH.Ultrastructurally, the bronchogenic carcinoma was composed of small undifferentiated and granulated cells. The granulated neoplastic cells had well developed organelles (endoplasmic reticulum, free ribosomes) concerned with protein synthesis. Secretion granules present in the tumor cells were small, surrounded by a limiting membrane, and resembled those reported in polypeptide hormone-secreting cells.

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“…Crude rabbit insulin w'as extracted from 50 g rabbit pancreas by the method of Mallory et al [6]. The method includes an extraction with acid-alcohol, precipitation of foreign proteins at pH 8.0 and precipitation of the insulin extract with ether.…”

Section: Methodsmentioning

confidence: 99%