Response of isolated ruminant mammary arteries to the long R3 analogue of insulin-like growth factor I.
Isolated mammary arteries from ruminants were used in a conventional organ bath system. Acetylcholine relaxed bovine but not ovine mammary arteries; both types responded to sodium nitroprusside. Noradrenaline (NA) caused a dose-dependent increase in generated tension. An analogue of insulin-like growth factor I (long R3-IGF-I) caused a rightward shift in the NA response curve in bovine vessels with intact endothelium (P < 0.02), and also in sheep arteries (P < 0.01). In bovine vessels, this effect was abolished when the endothelium was removed. The effect of long R3-IGF-I in bovine vessels was abolished by N -nitro-L-arginine methyl ester (L-NAME) an inhibitor of nitric oxide synthase, suggesting the effect of IGF-I on mammary arteries in vitro requires NO generation.
Gow
I F
IF
Integrative Metabolism Group, Hannah Research Institute, Ayr KA6 5HL, UK. gowi@hri.sari.ac.uk
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002417:Cattle; D004730:Endothelium, Vascular / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000031:analogs & derivatives* / Q000494:pharmacology; D007774:Lactation / Q000502:physiology; D008323:Mammary Arteries / Q000187:drug effects*; D008321:Mammary Glands, Animal / Q000098:blood supply; D018721:Muscarinic Agonists / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D009638:Norepinephrine / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D013045:Species Specificity; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D018721:Muscarinic Agonists; D014662:Vasoconstrictor Agents; C085700:long R(3)-insulin-like growth factor-I; D007334:Insulin-Like Growth Factor I; D002217:Carbachol; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester; D009638:Norepinephrine