Female rats were maintained on a protein-restricted diet 1 month prior to mating and throughout pregnancy. Their female offspring were maintained on a normal diet from birth or from weaning and were mated with normal males. The second generation offspring at birth still had significantly lower cerebral weight and total cerebral DNA (cerebral cell number).

No abstract

Abstract— Existing methods for the colorimetric (diphenylamine) determination of DNA content of brain have been modified for preserved cerebral hemispheres. On the average, right and left hemispheres (rat and chicken) contained similar amounts of DNA and one hemisphere could serve as a control for the other. All comparisons have been made with the values obtained for frozen brains (‘controls’). Preservation in 10 % (v/v) buffered formalin for 1 month introduced significant differences for both neonatal and adult cerebral hemispheres. On the other hand, preservation in 75 % (v/v) aqueous ethanol for 1 month did not introduce any significant differences in any of these determinations. Embedding in paraffin and subsequent clarification (removal of paraffin) did not further affect the DNA values of cerebral hemispheres preserved in formalin. Consequently it was possible to determine DNA in histological sections at the desired planes or even in parts of the sections. Micro‐modifications have been devised to determine colorimetrically the total DNA content of small brains (e.g. tadpoles) or of small parts of larger brains, as low as 25 μg of DNA/sample.

No abstract

The number of fetuses in the rat has been operatively restricted between 50 and 90% of normal by destruction of the other implantation sites by cauterization on the 8th day of pregnancy. The surviving offspring had significant increases in placental weights, body weights, cerebral weights, cerebral protein and cerebral DNA (cell number). Placental weights followed the extent of restriction.