Modification of age-induced changes in heme and hemoproteins by testosterone in male rats

Milad Sami Bitar, Myron Weiner

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Age-related changes in heme and hemoproteins, as well as the effect of testosterone treatment on these modifications were examined in male Sprague-Dawley rats. The activity of δ-aminolevulinic acid synthase (ALA-S) and the microsomal concentration of heme in aged rats were decreased by 37% and 33%, respectively, as compared to young values. In contrast, a marked increase in the activity of microsomal heme oxygenase (MHO) was seen in these animals. In aged rats, the level of cytochrome P-450 was decreased by 37%, as compared to young values. Furthermore, the activities of benzo[a]pyrene hydroxylase and aniline hydroxylase were decreased in proportion to the microsomal content of cytocyrome P-450. Steroid Δ4-hydrogenase, an index of endogenous substrate metabolism, exhibited no changes in activity during the aging process. The level of various hemoproteins such as cytochrome b5 and tryptophan pyrrolase in aged animals remained unaltered despite the decreased hepatic concentration of heme. It is worth noting that testosterone treatment of aged castrated rats restored the level of heme and cytochrome P-450 and the altered enzymatic activities of ALA-S and MHO to the "young" condition. In view of these findings, it is concluded that the events which lead to the low level of heme and cytochrome P-450 and its dependent mixed function oxidase activity during the senescent period could be due to increased rates of MHO and diminished ALA-S activities in these animals.

Original languageEnglish
Pages (from-to)285-296
Number of pages12
JournalMechanisms of Ageing and Development
Volume23
Issue number3-4
DOIs
Publication statusPublished - 12 Nov 1983

Keywords

  • Aged rats
  • Heme synthesis and degradation
  • Hemoproteins
  • Mixed function oxidase
  • Testosterone

Fingerprint Dive into the research topics of 'Modification of age-induced changes in heme and hemoproteins by testosterone in male rats'. Together they form a unique fingerprint.

  • Cite this