L. Friedman et al., GROWTH-PATTERNS IN SELECTED ORGANS OF THE MINIATURE SWINE AS DETERMINED BY GROSS MACROMOLECULAR-COMPOSITION, Journal of animal science, 73(5), 1995, pp. 1340-1350
As part of a larger study designed to characterize the early developme
ntal stages of the Hormel-Hanford strain miniature pig, the brain, kid
ney, liver, pancreas, and spleen from male animals were examined for c
hanges in RNA, DNA, and protein contents from 1 to 196 d after birth.
Distinct patterns were found for changes with age in macromolecular le
vels. Protein levels increased from d 1 to 56 in all organs except spl
een, in which little change was noted. Gel electrophoresis showed litt
le qualitative change in the liver protein profile during this period.
A fat-free, non-nucleic acid, protein-containing fraction, insoluble
in hot alkali, appeared in the brain after approximately 1 wk followin
g birth. DNA concentrations decreased markedly from d 1 to d 196 for b
rain, kidney, and spleen but decreased more gradually for liver and pa
ncreas. RNA levels declined slightly or remained the same in all organ
s except pancreas, where a large increase occurred from d 1 to weaning
(56 d). Growth proceeded in all organs by increases in cell number (h
yperplasia), as evidenced by increases in total (level or concentratio
n x organ weight) DNA, or by hypertrophy, as evidenced by increases in
the ratio of protein to DNA or by a combination of both processes. Hy
pertrophic growth was attained by d 56 and continued to sexual maturit
y in all organs except spleen. Hyperplastic growth continued to sexual
maturity in all organs except brain.