Postnatal brain growth and allometry in the rabbit Oryctolagus cuniculus.
A new four-parameter version of Pütter's growth curve (Pütter, 1920) recently developed by Jolicoeur and Pirlot (1988) is applied to cross-sectional data on brain and body weight in 66 male rabbits (Oryctolagus cuniculus) ranging up to one year in postnatal age. Apart from the olfactory bulb, in which there appears to be no initial delay, the estimated initial delays range from 21.7 days (after fertilization) for the cerebellum to 29.9 days for the cerebrum, which suggests that the weight of most regions of the brain, as well as body weight, start increasing rapidly only toward the end of pregnancy (30 days on the average). These initial delays may be related to the fact that rabbits are born very small, naked, blind, and helpless. Expressed on log-log scales, bivariate allometric trajectories have very diverse shapes, including approximate straight lines, curves possessing a single upward or downward convexity, and even sigmoid or inverted sigmoid curves. It seem doubtful whether, if age were unknown, a reasonably simple mathematical function could possess enough flexibility to describe all of these kinds of relationships satisfactorily.
Dawood
N
N
Department of Zoology, University of Madras, Guindy Campus, India.
Jolicoeur
P
P
Sharief
S D
SD
D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D001921:Brain / Q000254:growth & development*; D008297:Male; D009929:Organ Size; D011817:Rabbits / Q000254:growth & development*