Female rats were maintained on 8 or 27 percent protein diet by a pair-feeding schedule for 1 month before mating and throughout gestation. The brains of newborn rats from females on the 8 percent protein diet contained significantly less DNA and protein compared to the progeny of the females on the 27 percent diet. The data on DNA indicate that there are fewer cells; the protein content per cell was also lower. If, at birth, the brain cells are predominantly neurons, and their number becomes final at that time, then such dietary restriction may result in some permanent brain-neuron deficiency. This quantitative alteration in number as well as the qualitative one (protein per cell) may constitute a basis for the frequently reported impaired behavior of the offspring from protein-deprived mothers.

Evidence for smooth muscle cell hyperplasia was sought in elastic and muscular vessels of rabbits 2 weeks after hypertension had been induced by partial constriction of the abdominal aorta above both kidneys. In those arteries taken from the circulation proximal to the constriction, specifically the common carotid artery and the aorta, vessel length, wall thickness, weight, and deoxyribonucleic acid content were increased in proportion to the rise in arterial pressure. There was no change in the extracellular space of muscular arteries as measured by [14C]inulin. [3H]Thymidine uptake measured in a gastric artery increased in proportion to the rise in arterial pressure. As demonstrated by light microscope autoradiography, [3H]thymidine was incorporated into cells in all layers of the artery wall but predominantly into the smooth muscle cells. There was no change in the size of arteries below the ligature where the arterial pressure was within normal limits. The data demonstrated that the increase in vessel wall dimensions in this animal model of hypertension is due in part, during the acute phase, to an increase in the number of cells, particularly vascular smooth muscle cells.

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).

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