Model For Regulation Of Delta-Aminolevulinate Synthetase Induction In Rat-Liver

Padmanaban, G and Rao, MRS and Malathi, K (1973) Model For Regulation Of Delta-Aminolevulinate Synthetase Induction In Rat-Liver. In: Biochemical Journal, 134 (4). pp. 847-857.

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Abstract

A reciprocal relationship exists between the cytochrome P-450 content and d-aminolaevulinate synthetase activity in adult rats. In young rats the basal d-aminolaevulinate synthetase activity is higher and the cytochrome P-450 content is lower compared with the adult rat liver. Administration of allylisopropylacetamide neither induces the enzyme nor causes degradation of cytochrome P-450 in the young rat liver, unlike adult rat liver. Allylisopropylacetamide fails to induce d-aminolaevulinate synthetase in adrenalectomized–ovariectomized animals or intact animals pretreated with successive doses of the drug, in the absence of cortisol. The cortisol-mediated induction of the enzyme is sensitive to actinomycin D. Allylisopropylacetamide administration degrades microsomal haem but not nuclear haem. Haem does not counteract the decrease in cytochrome P-450 content caused by allylisopropylacetamide administration, but there is evidence for the formation of drug-resistant protein-bound haem in liver microsomal material under these conditions. Phenobarbital induces d-aminolaevulinate synthetase under conditions when there is no breakdown of cytochrome P-450. On the basis of these results and those already published, a model is proposed for the regulation of d-aminolaevulinate synthetase induction in rat liver.

Item Type:	Journal Article
Publication:	Biochemical Journal
Publisher:	Portland Press
Additional Information:	Copyright of this article belongs to Portland Press.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	14 Jul 2010 04:57
Last Modified:	19 Sep 2010 06:10
URI:	http://eprints.iisc.ac.in/id/eprint/28718

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