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S. C. Kirkland
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M. L. Ellison
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ABSTRACT

The production of corticotrophin releasing factor (CRF) activity by human tumour cells in monolayer culture was investigated. The secretion of CRF activity by a bronchial carcinoid cell line was demonstrated using a rat pituitary cell monolayer system. The long-term production (5 years) of CRF activity suggested the synthesis and secretion of active factors by the tumour cells.

The CRF activity was concentrated from medium previously exposed to the tumour cells using batchwise extraction on columns packed with ODS. When these extracts were fractionated by analytical high pressure liquid chromatography, the CRF activity was resolved into two molecular forms.

J. Endocr. (1984) 103, 85–90

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S. C. KIRKLAND
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M. L. ELLISON
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The posterior pituitary gland is considered to be a source of a corticotrophin releasing factor(s) distinct from vasopressin. In this study, the corticotrophin releasing activity of a commercial posterior pituitary extract (Pitressin) and synthetic vasopressin were compared, using a perfused rat pituitary monolayer system. Pitressin was shown to have approximately twice the releasing activity than could be accounted for by its vasopressin content. Fractionation of the posterior pituitary extract, using high pressure liquid chromatography, showed it to contain active material co-eluting with synthetic vasopressin, and at least three other corticotrophin releasing factors. The releasing activity of the most active of these factors was investigated and was found to stimulate ACTH release in a dose-related manner.

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S. C. Kirkland
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J. L. Lumsden
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M. L. Ellison
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ABSTRACT

The nature of corticotrophin releasing factor (CRF) activity secreted by a human bronchial carcinoid cell line was investigated. The CRF activity in incubation media exposed to bronchial tumour cells was concentrated by preparative high pressure liquid chromatography (HPLC). Analytical HPLC resolved the CRF activity into several different forms.

The incorporation of [3H]leucine and other [3H]amino acids into materials which co-eluted with CRF activity when fractionated by analytical HPLC suggested that the bronchial carcinoid cells were secreting peptide CRF(s). The most abundant radioactive material was shown to have a molecular weight of 12 000 by sodium dodecyl sulphate gel electrophoresis. This radioactive fraction also stimulated ACTH secretion by rat pituitary cell cultures in a dose-responsive manner.

J. Endocr. (1984) 103, 91–96

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