Endocrine control of daily variations in hepatic mixed function oxidase activity in the adult male rat
Titel:
Endocrine control of daily variations in hepatic mixed function oxidase activity in the adult male rat
Auteur:
Miller, Margaret Ann Colas, Antonio E.
Verschenen in:
Biological rhythm research
Paginering:
Jaargang 13 (1982) nr. 3 pagina's 209-218
Jaar:
1982-10
Inhoud:
The hormonal control of rhythmic fluctuations in hepatic microsomal mixed function oxidase activity was examined by incubating microsomes prepared from intact control, sham-operated, pinealectomized (PX), adrenalectomized (AX), and pinealectomized-adrenalectomized (PXAX) adult male rats with aminopyrine (AP) and [4-C14]3ss-hydroxy-5-androsten-17-one (DHA). The animals were kept on a 12:12 light-dark cycle for 15 days prior to killingatl, 4, 6 and 10 hafter light and at 1, 4, 6 and 10 h after dark. The rate of both the N-demethylation of AP and the 7α-hydroxy lation of DHA varies diurnally with maximal and minimal activities in the dark and light periods, respectively. The fluctuation in both reactions fits a symmetric sine curve for all endocrine treatment groups except for the 7α-hydroxylation in PX animals. PXAX was the only treatment resulting in a significant increase in 7α-hydroxylase activity. The data suggest that the pineal may be involved in mediating the effects of environmental light on liver 7α-hydroxylase activity.
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