title: Organ growth functions in maturing male Sprague-Dawley rats based on a collective database.
abstract: Ten different organ weights (liver, spleen, kidneys, heart, lungs, brain, adrenals, testes, epididymes, and seminal vesicles) of male Sprague-Dawley (S-D) rats of different ages (1-280 d) were extracted based on a thorough literature survey database. A generalized Michaelis-Menten (GMM) model, used to fit organ weights versus age in a previous study (Schoeffner et al., 1999) based on a limited data, was used to find the best fit model for the present expanded data compilation. The GMM model has the functional form: Wt = (Wt(o).K(gamma) + Wt(max).Age(gamma))/(K(gamma) + Age(gamma)) where Wt is organ/tissue weight at a specified age, Wt(o) and Wt(max) are weight at birth and maximal growth, respectively, and K and gamma are constants. Organ weights were significantly correlated with their respective ages for all organs and tissues. GMM-derived organ growth and percent body weight (%BW) fractions of different tissues were plotted against animal age and compared with experimental values as well as previously published models. The GMM-based organ growth and %BW fraction profiles were in general agreement with our empirical data as well as with previous studies. The present model was compared with the GMM model developed previously for six organs--liver, spleen, kidneys, heart, lungs, and brain--based on a limited data, and no significant difference was noticed between the two sets of predictions. It was concluded that the GMM models presented herein for different male S-D rats organs (liver, spleen, kidneys, heart, lungs, brain, adrenals, testes, epididymes, and seminal vesicles) are capable of predicting organ weights and %BW ratios accurately at different ages.
authors.affiliation: Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, Georgia, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Mirfazaelian
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Fisher
mesh_terms: D000367:Age Factors; D000818:Animals; D016208:Databases, Factual / Q000706:statistics & numerical data; D008297:Male; D008962:Models, Theoretical; D009929:Organ Size; D010599:Pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000033:anatomy & histology / Q000254:growth & development*; D012016:Reference Values