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.

Animals↗

PubMed1966

Norepinephrine methylation in fetal rat adrenals.

The activity of phenylethanolamine-N-methyl transferase, the enzyme that methylates norepinephrine to form epinephrine, increases rapidly in the fetal rat adrenal during the day preceding epinephrine accumulation. The developmental increase in enzyme activity and the accumulation of epinephrine are prevented by fetal hypophysectomy (decapitation). Administration of adrenocorticotrophic hormone or cortisol acetate largely reverses the effect of fetal decapitation.

Adrenal Glands↗

PubMed1965

Delta-aminolevulinate dehydratase activity in mice with hereditary anemia.

Homozygous (f/f) but not heterozygous (f/+) mice of the highly congenic strain, FL/ Re, manifest a severe transitory siderocytic fetal anemia. Adults of both f/f and f/+ genotype manifest decreased hepatic, splenic, and renal levels of triangle up-amino-levulinate dehydratase (ALD) activity compared to homozygous (+/+) mice of the same strain. The degree of augmentation in splenic ALD activity following phenylhydrazine administration is high in +/+, intermediate in f/+, and low in f/f mice. These findings suggest that perhaps a deficiency in the fetal level of ALD may be responsible for the transitory fetal anemia.

Anemia↗

PubMedDate not supplied

Expression of tyrosine hydroxylase in the aging, rodent olfactory system.

Tyrosine hydroxylase (TH) mRNA, immunoreactivity, and activity were examined as a reflection of dopamine expression in juxtaglomerular neurons intrinsic to the olfactory bulbs of young (6-month-old), middle aged (18-month-old), and aged (25- to 29-month-old) rats and mice. TH expression was maintained at levels observed in young animals in the olfactory bulbs of aged animals from two mouse strains, C57Bl/6JNia and C57Bl/6NNia, and one rat strain, an F1 hybrid between F344 and Brown Norway strains. The parental F344 rat strain exhibited reductions in TH expression of about 20% in 26- to 29-month-old animals as compared to 6- and 18 month-old rats. However, there was significant inter-animal variability. Some aged F344 rats had TH levels that were similar and others had activity levels that were 50% of those in young and middle aged animals. Neither the general condition of the animals nor the presence of adrenal tumors predicted the individuals with reduced TH expression. Olfactory bulb size, estimated from protein content, did not differ between rats and mice of different ages. In addition, expression of olfactory marker protein, a protein found primarily in mature olfactory receptor neurons, also was unchanged indicating the maintenance of afferent innervation. These data suggest that, in contrast to other brain dopamine systems, the expression of the dopamine phenotype is maintained in the aging olfactory bulb.

Aging↗