title: Brain-tissue accumulation of fluorescent age pigments in four poeciliid fishes (cyprinodontiformes) and the estimation of "biological age".
abstract: The concept of an intrinsic "biological age" or "physiological age" is very important in comparative ecological and evolutionary studies, but its implementation has been problematic. Although many authors have discussed the importance of intrinsic measures of age over the past 75 years, only Reiss (1989 ) has proposed an operational definition in terms of cumulative metabolism; however, Reiss' measure cannot be easily applied to assessing the age of individual organisms. Measurement of the level of accumulation of fluorescent age pigments (particularly lipofuscins) in post-mitotic tissues, which seems to occur at a rate proportional to cumulative metabolism, in principle provides a mechanism for estimating the biological age of individual organisms. This study has shown that brain-tissue FAP levels vary in direct proportion to chronological age and body size within four species of poeciliid fishes, and has documented interspecific differences in rate of accumulation of fluorescent age pigments, differences that seem to be a function of the degrees of relatedness. Rather than proposing that FAP level by itself be used as a measure of biological age, however, I propose that it be used in conjunction with other estimates, such as chronological age and body size, to derive a composite "age factor."
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock 79409-3131, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Strauss
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001824:Body Constitution; D001835:Body Weight; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D003532:Cyprinodontiformes / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism*; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D008062:Lipofuscin / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D010860:Pigments, Biological / Q000378:metabolism*; D011036:Poecilia / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism*; D013045:Species Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D008062:Lipofuscin; D010860:Pigments, Biological