Differential effects of somatostatin and its analog on protein tyrosine kinases activity in the rat pituitary and the murine colonic tumors.
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.
Pawlikowski
M
M
Department of Experimental Endocrinology, Institute of Endocrinology, Lodz, Poland.
Lachowicz
L
L
Kunert-Radek
J
J
Winczyk
K
K
Janiszewska
G
G
Szkudlarek
J
J
D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D015282:Octreotide / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000201:enzymology*; D010911:Pituitary Neoplasms / Q000188:drug therapy / Q000201:enzymology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017481:Receptors, Somatostatin / Q000145:classification / Q000187:drug effects / Q000378:metabolism; D013004:Somatostatin / Q000494:pharmacology*
D018931:Antineoplastic Agents, Hormonal; D004791:Enzyme Inhibitors; D017481:Receptors, Somatostatin; D013004:Somatostatin; D011505:Protein-Tyrosine Kinases; D015282:Octreotide