title: Effects of caloric restriction and aging on erythrocyte membrane Ca(2+)-ATPase activity in specific pathogen-free Fischer 344 rats.
abstract: Dietary caloric restriction extends life span in the Fischer 344 rat. The interaction of aging and caloric restriction was examined at the level of the plasma membrane transport-associated enzymes, Ca(2+)-adenosine triphosphatase (ATPase) and Na,K-ATPase, in the Fischer rat. Animals were in four age groups, ranging from 6.1 to 25.0 months, and were specific pathogen-free (SPF, barrier-raised). Results from male and female animals raised on an ad libitum diet were compared with those from rats that received 60% of the age-specific caloric intake of their ad lib littermates. The responses of erythrocyte membrane Ca(2+)-ATPase activity in vitro to thyroid hormone (L-thyroxine [T4]; 3,5,3'-triiodothyronine [T3]) and to purified calmodulin, a Ca(2+)-binding protein activator of Ca(2+)-ATPase, were measured. Erythrocyte membrane Na,K-ATPase was also compared in the two diet groups, as was plasma glucose. Plasma membrane Ca(2+)-ATPase activity in the absence of added thyroid hormone and calmodulin was significantly reduced in calorically restricted rats (-39%, P less than .001), compared with ad lib-fed animals, and the response was similar in the four age groups aged 6.1, 12.7, 17.0, and 25.0 months. In contrast, pooled (all ages) Ca(2+)-ATPase response in vitro to T4 and to T3 in calorically restricted animals was enhanced compared with the ad lib group (+62% and +58%, P less than .001, respectively). Calmodulin responsiveness of the enzyme was increased by 45% (P less than .001) in calorie-deprived animals, similar to the change in T4 and T3 responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, State University of New York, Buffalo.
authors.forename: F B
authors.initials: FB
authors.lastname: Davis
authors.forename: M R
authors.initials: MR
authors.lastname: Deziel
authors.forename: J B
authors.initials: JB
authors.lastname: Van Liew
authors.forename: P J
authors.initials: PJ
authors.lastname: Davis
authors.forename: L L
authors.initials: LL
authors.lastname: Bernardis
authors.forename: S D
authors.initials: SD
authors.lastname: Blas
mesh_terms: D000375:Aging / Q000097:blood*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology; D004032:Diet; D004435:Eating; D002149:Energy Intake; D004910:Erythrocyte Membrane / Q000201:enzymology*; D005260:Female; D005856:Germ-Free Life; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D011916:Rats, Inbred F344; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013963:Thyroid Hormones / Q000494:pharmacology; D013974:Thyroxine / Q000097:blood; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D002147:Calmodulin; D013963:Thyroid Hormones; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D013974:Thyroxine