EMBRYONIC AND POSTNATAL-GROWTH OF RAT AND MOUSE .5. PRENATAL GROWTH OF ORGANS AND TISSUES, GENERAL PRINCIPLES - ALLOMETRIC GROWTH, ABSENCE OF GROWTH, AND GENETIC-REGULATION OF GROWTH PROCESS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 98  (2) , 162-182
Abstract
The investigation yielded several general growth principles, i.e., types of growth occurring rather frequently: allometric growth; a non-changing growth rate, persisting when the growth rate changes in the majority of tissues; a growth rate equal to that of the whole embryo; absence of growth; and jumps, i.e., changes in the volume or surface of organs completed within about half a day or less and probably due to changes in the cell volume or surface area. These histological changes started simultaneously with the changes in growth rate. Growth constants had a value of about 2.0 in the prenatal period, as in the postnatal period. During development their value increased slightly but significantly. Further arguments were given for the mitosis-regulating model previously. The mitosis-regulating model combined with the general growth principles derived here and previously constituted a comprehensive model for the genetic regulation of the growth process.