Changes in plasma glucose and lactate evoked by alpha and beta 2-adrenoceptor stimulation in conscious fasted rabbits.
In conscious fasted rabbits, the iv infusion of salbutamol (3 micrograms/kg per min) and clonidine (2 micrograms/kg per min) induced a blood glucose increase amenable to blockade, respectively by ICI 118551 (1 micrograms/kg per min) and idazoxan (20 micrograms/kg per min). Amidephrine (10 micrograms/kg per min) and salbutamol mediated an increase in plasma lactate which was attenuated by prazosin (50 micrograms/kg, sc) and ICI 118551 respectively. Clonidine did not alter basal plasma lactate. The iv infusion of adrenaline (0.3 micrograms/kg per min) evoked an increase in plasma lactate more sensitive to blockade by ICI 118551 than by prazosin. ICI 118551 also shortened the hyperglycaemic response to adrenaline, 3-Mercaptopicolinic acid (25 mg/kg) reduced salbutamol- and adrenaline-mediated hyperglycaemia and increased at the same time the lactate/glucose ratio. Our data show that plasma lactate levels may be regulated by alpha 1- and beta 2-excitatory adrenoceptor stimulation. However, only the increase in blood lactate derived from beta 2-adrenergic stimulation seems to contribute to the overall catecholamine-mediated hyperglycaemia.
Reverte
M
M
Departemento de Farmacologia, Facultad de Medicina, Universidad de Salamanca, Spain.
Garcia-Barrado
M J
MJ
Moratinos
J
J
D000420:Albuterol / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000032:analysis* / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology*; D004146:Dioxanes / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005215:Fasting; D019329:Idazoxan; D007773:Lactates / Q000097:blood*; D008297:Male; D010848:Picolinic Acids / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D013053:Spectrophotometry
D001786:Blood Glucose; D004146:Dioxanes; D007773:Lactates; D010848:Picolinic Acids; D011412:Propanolamines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; C008363:3-mercaptopicolinic acid; D003000:Clonidine; D000420:Albuterol; D011224:Prazosin; D019329:Idazoxan; D004837:Epinephrine