Effect of ICV infusion of CRF on blood pressure and adrenal steroids in rabbits.
The effect of prolonged, 22 h long, intracerebroventricular (i.c.v.) infusion of corticotropin-releasing hormone (CRF) on plasma cortisol, corticosterone and electrolyte concentrations, mean arterial blood pressure (MAP) and heart rate (HR) were investigated in conscious rabbits. During i.c.v. infusion of CRF, 1 and 3 micrograms/h, at a rate of 17 microliters/h, plasma cortisol and corticosterone concentrations rose to the level noted after ACTH stimulation in rabbits. Plasma [Na] did not change, but plasma [K] was reduced and plasma osmolality increased during the infusion of CRF, 3 micrograms/h. MAP and HR, recorded continuously during i.c.v. infusion of CRF, changed only with the higher dose of CRF: MAP was elevated during the first 5 h of infusion, and then returned to the control level. HR was lower than control at the end of the first hour of infusion and again between 9 and 15 h of infusion. The prolonged rise of CRF concentration in the brain induced a sustained rise in circulating adrenal steroid hormones. MAP did not increase to the level noted after bolus i.c.v. injection of CRF and the rise in MAP was not sustained.
Tarjan
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Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria, Australia.
Ferraro
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May
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D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006854:Hydrocortisone / Q000097:blood*; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood; D011817:Rabbits; D012964:Sodium / Q000097:blood; D012965:Sodium Chloride / Q000008:administration & dosage
D012965:Sodium Chloride; D003346:Corticotropin-Releasing Hormone; D012964:Sodium; D011188:Potassium; D003345:Corticosterone; D006854:Hydrocortisone