title: Aging and activity of 5-aminolevulinate hydrolyase in the blood of humans and rats.
abstract: Activity of 5-aminolevulinate hydrolyase (delta-aminolevulinic acid dehydrase, ALAD, EC 4.2.1.24) in the blood was determined in relation to age in humans and rats, and the following findings were obtained: (1) In the group which consisted of 47 women (mean age 46, ranged 24 to 62 years) living in a rural district, where the atmospheric lead concentration was 0.5 micron/m3, a significant negative correlation between ALAD activity and age was observed statistically (r = -0.54). However, in the group which consisted of 53 women of similar age group living in an urban district, where the atmospheric lead concentration was 1.9 microng/m3, showed a lower level of the ALAD activity than that of the former group and no correlation was found r = -0.01) between ALAD activity and age. (2) The ALAD activity of intact rats showed a decrease with age. The decrease proceeds rapidly within 8 weeks of age and becomes stable after reaching 25 weeks of age or 300 g of body weight. The value of the activity after 25 weeks of age was about one tenth of that at 5 weeks of age or 100 to 130 g of body weight. (3) Fifteen intact rats weighing 240 to 705 g were divided into three groups according to their body weight and were injected with lead acetate solution equivalent to 1 mg Pb/kg intraperitoneally in order to examine the sensitivity to lead in rats that have variation of ALAD activity by age or by body weight. The ALAD activity of these rats fell to the same level in all groups independently of the activity or the body weight before injection.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D000397:Air Pollution / Q000032:analysis; D000818:Animals; D001835:Body Weight; D005260:Female; D006801:Humans; D006836:Hydro-Lyases / Q000097:blood*; D007854:Lead / Q000032:analysis / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D000623:Porphobilinogen Synthase / Q000097:blood*; D051381:Rats
chemical_list: D007854:Lead; D006836:Hydro-Lyases; D000623:Porphobilinogen Synthase