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Bombesin production by human small cell carcinoma of the lung
66
BOMHESIN PRODUCTION BY HUMAN SMALL CELL CARCINOMA
OF THE LUNG
S R Bloom, M A Ghatei, C C Cate*,
*O S Pettengill, & *G D Sorenmon Department of Medicine, Hammersmlth Hospital, London UK and *Department of pathology, Dartmouth Medical School, Hanover, USA. Bombesin, a tetradecepeptide, isolated initially fram amphibian skin has mammalian c~unterparts including gastrin-releasing peptide (GRP), found in mammalian brain end gut. In human foetal lung, cells with bombesin-like Immunoreectivity (BLI) are found in bronchial and bronchiolar epithelium. Continuous cell lines have been established utilizing tumour fram patients with small cell carciname of the lung (SCCL), which produce a variety of peptide, glycoprotein and steroid hormones. Media from these cultured cells as well as plasma specimens frum patients with SCCL have been evaluated for BLI by a specific and sensitive radioimmunoassay using an antisertun directed to the C-terminal portion of amphibian b a n b e s i n w h i c h completely crossreacts with mammalian GRP. Continuous cell lines of SCCL have bean maintained in RPMI 1640 or Waymouth's MB 752/L medium with 20% foetal calf serum. Cultures were sub-cultured at 5 x 105 cells/ml and the medium harvested after 4 days. Elevated levels of HLI were found in the medium from 8 of 10 cell lines, reaching e maximum level of 1500 pmol/1. Plasma levels were more than 80 pmol/l in 2 out of 16 randumly selected patients with SCCS. A culture established from the tumour of a patient with the highest plasma level of BLI (1240 pmol/l) was also the highest producer in vitro. Column chromatography of plasma and culture media revealed two main immunoreactive peaks coeluting with GRP (Kay - 0.54) end ~mphibian bambesin (Kay = 0.89). Thus, b(~nbesin-related paptides can be produced in massive quantities by human small cell carcinama in man and may account for some of the ill-understood non-metastatic clinical manifestation of this condition. EFFECTS OF SUBSTANCE P IN THE HIPPOCAMPAL SLICE PREPARATION SUBSTANCE P AND SUBSTANCE P FIBRILLARY POLYMERS.
- ACTIVITY OF
R J Boakes, J M Candy, J Ednie, R H Perry, A Oakley and J A Edwardson, MRC Neuroendocrinology Unit, Newcastle General Hospital, England. Substance P readily forms stable fibrillary polymeric aggregates under conditions that are used in the preparation of peptide solutions for electrophysiological studies. Thus, in a physiological medium, electron microscopic observations show that substance P forms laterally aggregated fibrils which do not disaggregate on 1,OOO fold dilution. We have used hippocampal slices to investigate whether the formation of substance P polymers interferes with the action of superfused solutions of the peptide. In conditions designed to minimise fibril formation substance P, dissolved directly at the appropriate concentration (10 -4 - IO-6M) in Krebs buffer and superfused immediately after preparatipn onto the hippocampus, consistently elicited a prolonged increase in the synaptically evoked population spike amplitude. This action showed desensitisation to subsequently superfused solutions of the peptide. In contrast superfusion of a lO-5M substance P solution, prepared by diluting a 1.5mMstock solution that had been allowed to stand for 24h to enhance polymer formation, had no effect on the population spike amplitude and did not cause desensitisation to subsequent superfusion of a freshly prepared 10-4M solution of substance P. These findings indicate that substance P increases the excitability of hippocampal slice preparations and that the method of preparation of substance P solutions (which influences the extent of polymer formation) may be a critical factor in determining the electrophysiological actions of substance P.
BOMHESIN PRODUCTION BY HUMAN SMALL CELL CARCINOMA
OF THE LUNG
S R Bloom, M A Ghatei, C C Cate*,
*O S Pettengill, & *G D Sorenmon Department of Medicine, Hammersmlth Hospital, London UK and *Department of pathology, Dartmouth Medical School, Hanover, USA. Bombesin, a tetradecepeptide, isolated initially fram amphibian skin has mammalian c~unterparts including gastrin-releasing peptide (GRP), found in mammalian brain end gut. In human foetal lung, cells with bombesin-like Immunoreectivity (BLI) are found in bronchial and bronchiolar epithelium. Continuous cell lines have been established utilizing tumour fram patients with small cell carciname of the lung (SCCL), which produce a variety of peptide, glycoprotein and steroid hormones. Media from these cultured cells as well as plasma specimens frum patients with SCCL have been evaluated for BLI by a specific and sensitive radioimmunoassay using an antisertun directed to the C-terminal portion of amphibian b a n b e s i n w h i c h completely crossreacts with mammalian GRP. Continuous cell lines of SCCL have bean maintained in RPMI 1640 or Waymouth's MB 752/L medium with 20% foetal calf serum. Cultures were sub-cultured at 5 x 105 cells/ml and the medium harvested after 4 days. Elevated levels of HLI were found in the medium from 8 of 10 cell lines, reaching e maximum level of 1500 pmol/1. Plasma levels were more than 80 pmol/l in 2 out of 16 randumly selected patients with SCCS. A culture established from the tumour of a patient with the highest plasma level of BLI (1240 pmol/l) was also the highest producer in vitro. Column chromatography of plasma and culture media revealed two main immunoreactive peaks coeluting with GRP (Kay - 0.54) end ~mphibian bambesin (Kay = 0.89). Thus, b(~nbesin-related paptides can be produced in massive quantities by human small cell carcinama in man and may account for some of the ill-understood non-metastatic clinical manifestation of this condition. EFFECTS OF SUBSTANCE P IN THE HIPPOCAMPAL SLICE PREPARATION SUBSTANCE P AND SUBSTANCE P FIBRILLARY POLYMERS.
- ACTIVITY OF
R J Boakes, J M Candy, J Ednie, R H Perry, A Oakley and J A Edwardson, MRC Neuroendocrinology Unit, Newcastle General Hospital, England. Substance P readily forms stable fibrillary polymeric aggregates under conditions that are used in the preparation of peptide solutions for electrophysiological studies. Thus, in a physiological medium, electron microscopic observations show that substance P forms laterally aggregated fibrils which do not disaggregate on 1,OOO fold dilution. We have used hippocampal slices to investigate whether the formation of substance P polymers interferes with the action of superfused solutions of the peptide. In conditions designed to minimise fibril formation substance P, dissolved directly at the appropriate concentration (10 -4 - IO-6M) in Krebs buffer and superfused immediately after preparatipn onto the hippocampus, consistently elicited a prolonged increase in the synaptically evoked population spike amplitude. This action showed desensitisation to subsequently superfused solutions of the peptide. In contrast superfusion of a lO-5M substance P solution, prepared by diluting a 1.5mMstock solution that had been allowed to stand for 24h to enhance polymer formation, had no effect on the population spike amplitude and did not cause desensitisation to subsequent superfusion of a freshly prepared 10-4M solution of substance P. These findings indicate that substance P increases the excitability of hippocampal slice preparations and that the method of preparation of substance P solutions (which influences the extent of polymer formation) may be a critical factor in determining the electrophysiological actions of substance P.