Alpha 1-adrenergic stimulation of inositide hydrolysis in liver of senescent rats.
Hydrolysis of phosphatidyl inositides (PI) was measured in response to alpha 1-adrenergic agonist in slices of liver prepared from F-344 female rats aged 6-, 15- and 25 months. Tissue was labeled with [3H]inositol and release of inositol phosphates was measured following a 60-min incubation with a range of concentrations of l-epinephrine. The response to epinephrine was completely blocked by prazosin, indicating the involvement of alpha 1-adrenergic receptors. The maximum response to epinephrine represented release of 13-15% of radioactivity incorporated into the pool of cellular lipids and was unchanged with age. The concentration of epinephrine required for half-maximal stimulation was 1-1.5 microM and was also unchanged with age. These data suggest that, although senescence is accompanied by alterations with age in the liver alpha 1-receptor, alpha 1-stimulation of PI hydrolysis is unchanged.
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Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville, Florida 32608.
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D000375:Aging / Q000378:metabolism*; D000818:Animals; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006868:Hydrolysis; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*
D010716:Phosphatidylinositols; D011942:Receptors, Adrenergic, alpha; D011224:Prazosin; D004837:Epinephrine