Regulatory effects of 5 beta-reduced steroids.
J Steroid Biochem Mol Biol
; 39(2): 253-63, 1991 Aug.
Article
em En
| MEDLINE
| ID: mdl-1888686
The first section of this publication summarizes early work according to which 5 beta-pregnanedione is an important metabolite of progesterone in the early stages of the chick embryo's adrenal steroidogenesis, then decreasing gradually as corticosteroidogenesis increases. In the second section a model is described in which adrenal 3 beta-ol hydroxylase-isomerase of the 17-day-old chicken is suppressed pharmacologically, this suppression being correlated with that of the synthesis of aminoevulinic acid (ALA), the first and rate-limiting step of the heme pathway. 5 beta-Pregnanedione (10(-7)-10(-6) M) restored ALA synthesis in this inhibited model to normal values. The effect of 5 beta-pregnanedione was specific since other steroids tested: progesterone; 5 alpha-pregnanedione; corticosterone or estradiol, did not stimulate ALA. Since heme formation by steroidogenic glands contributes to the synthesis of cytochrome P450 rather than hemoglobin, 5 beta-pregnanedione was also assayed as a stimulator of this enzyme system and was found to increase cytochrome P450 in adrenals and testes but not in the liver. In view of these results a hypothesis is advanced according to which 5 beta-reduced progestagens and androgens stimulate cytochrome P450 formation, i.e. the synthesis of progesterone and higher hydroxylated steroids, by steroidogenic glands in the event of an excessive precursor reduction.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Esteroides
Limite:
Animals
Idioma:
En
Revista:
J Steroid Biochem Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido