Hyperplastic and Hypertrophic Growth in Organs and Tissues of the Neonatal Pig

Abstract

Five Yorkshire pigs, suckled by their dams, were slaughtered at each of six ages, 0, 10, 20, 30, 40 and 50 days. Total weights and tissue samples were taken of liver, heart, kidney, lung, brain and gastrocnemius muscle for determination of protein, DNA and RNA contents. Total DNA, an index of nucleus number, increased in all tissues throughout the 50 days but at a declining rate in brain and lung after 20 days; overall increase was greatest in muscle and least in brain. Ratio of protein to DNA, an index of cell size, increased throughout in all tissues with, again, the greatest increase occurring in muscle and the least in brain. An alternative index of cell size, the ratio of organ weight to its DNA content, showed less difference between tissues but a similar ranking. Ratio of RNA:DNA, an index of cellular activity, changed relatively little in any tissue but tended to increase in liver and brain and decline in muscle. The tissue protein concentration increased appreciably in muscle and changed very little in brain and lung. Copyright © 1977. American Society of Animal Science . Copyright 1977 by American Society of Animal Science.