Abstract
The effects of the native somatostatin-14 (SST-14) and of its analog octreotide (OCT) on the activity of protein tyrosine kinases (PTK) in the normal rat anterior pituitary gland, diethylstilbestrol (DES)-induced rat pituitary tumor and murine colonic cancer Colon 38 were studied in vitro. PTK activity was estimated in tissue homogenates using gamma-[32P]ATP and poly (Glu80, Tyr20) as a substrate. It was found that both SST-14 and OCT suppressed the PTK activity in all examined tissues. The suppressive effect was more pronounced in DES-induced pituitary tumor than in normal anterior pituitary gland, and in the former, OCT was more effective than SST-14. In contrast, SST-14 stronger suppressed PTK activity in colonic cancer than OCT. We hypothesize that SST-14 acts on PTK activity in colonic cancer mainly via SSTR-1 subtype of somatostatin receptors.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antineoplastic Agents, Hormonal / pharmacology*
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Colonic Neoplasms / drug therapy*
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Colonic Neoplasms / enzymology*
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Enzyme Inhibitors / pharmacology
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In Vitro Techniques
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Male
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Mice
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Mice, Inbred C57BL
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Mice, Inbred DBA
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Octreotide / pharmacology*
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Pituitary Gland, Anterior / drug effects*
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Pituitary Gland, Anterior / enzymology*
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Pituitary Neoplasms / drug therapy
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Pituitary Neoplasms / enzymology
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Protein-Tyrosine Kinases / antagonists & inhibitors
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Protein-Tyrosine Kinases / metabolism*
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Rats
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Rats, Wistar
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Receptors, Somatostatin / classification
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Receptors, Somatostatin / drug effects
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Receptors, Somatostatin / metabolism
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Somatostatin / pharmacology*
Substances
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Antineoplastic Agents, Hormonal
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Enzyme Inhibitors
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Receptors, Somatostatin
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Somatostatin
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Protein-Tyrosine Kinases
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Octreotide