Effects of thyroxine and thyroidectomy on the hydroxylation of testosterone by liver microsomes from male and female rats

1970 ◽  
Vol 208 (1) ◽  
pp. 116-124 ◽  
Author(s):  
Ryuichi Kato ◽  
Atsushi Takahashi ◽  
Yoshishito Omori
Keyword(s):  
Liver Microsomes ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats

DOSE-DEPENDENT EFFECTS OF ETHINYLOESTRADIOL, DIETHYLSTILBOESTROL AND OESTRADIOL ON THE METABOLISM OF 4-ANDROSTENE-3, 17-DIONE IN RAT LIVER MICROSOMES

1975 ◽  
Vol 78 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Kurt Einarsson ◽  
Jan-Åke Gustafsson ◽  
Jan Sjövall ◽  
Eberhard Zietz
Keyword(s):  
Enzyme Activities ◽  
Liver Microsomes ◽  
Female Rats ◽  
Rat Liver Microsomes ◽  
Microsomal Enzyme ◽  
Male And Female ◽  
Inhibiting Effect ◽  
Male And Female Rats ◽  
Metabolizing Enzyme ◽  
Dose Dependent

ABSTRACT The effects of administration of ethinyloestradiol (EtE2), 0.1, 0.5 or 1 μg per day, diethylstilboestrol, 5, 100 or 500 μg per day, and oestradiol, 1 or 100μg per day for 12 days on the hepatic microsomal metabolism of 4-[4-14C]androstene-3,17-dione were studied in castrated male and female rats. When rats were given EtE2 in daily doses of 0.1 and 0.5 μg the activities of the 3α- and 17β-hydroxysteroid oxidoreductases increased in both male and female rats. A similar tendency was noted for the 5α-reductase in female rats. On the other hand, the activities of the 3β-hydroxysteroid oxidoreductase and 7α-hydroxylase enzyme systems were suppressed in both male and female rats already after administration of 0.1 μg of EtE2. Diethylstilboestrol, administered in doses of 100 and 500 μg, and oestradiol, given in a dose of 100 μg, suppressed the microsomal enzyme activities whereas the lower doses of 5 μg of diethylstilboestrol and 1 μg of oestradiol were without effects. The results indicate that oestrogenic compounds given in doses higher than the physiological one have a suppressing effect on microsomal steroid metabolizing enzyme activities. Ethinyloestradiol has a stimulating effect on certain microsomal enzyme activities and an inhibiting effect on others when administered in an amount of 0.5 μg · kg−1 per day. The findings are discussed in relation to recent reports on impaired drug metabolism in women taking contraceptives.

THE EFFECT OF NEONATAL ADMINISTRATION OF SEX HORMONES ON THE TURNOVER OF HEPATIC MICROSOMAL PHOSPHOLIPID IN MALE AND FEMALE RATS

1971 ◽  
Vol 49 (4) ◽  
pp. 659-665 ◽  
Author(s):  
Y. C. TOH
Keyword(s):  
Testosterone Propionate ◽  
Liver Microsomes ◽  
Total Content ◽  
P Uptake ◽  
Female Rats ◽  
Radioactive Phosphorus ◽  
Male And Female ◽  
Male And Female Rats ◽  
Neonatal Administration ◽  
Microsomal Phospholipid

SUMMARY The effect of neonatal administration of testosterone propionate and oestradiol benzoate on the metabolism of microsomal phospholipid in the liver of male and female rats was studied. Males had a greater uptake of radioactive phosphorus than females. Gonadectomy at the age of 4 weeks reduced the incorporation of 32P into the microsomal phospholipid. Administration of testosterone significantly increased 32P uptake both in the intact and ovariectomized females as well as in the castrated males, whereas oestradiol produced no effect. A sex difference of total microsomal phospholipid phosphorus was also found in the gonadectomized rats. Oestrogen caused no change in the intact animals but restored the level of phospholipid in ovariectomized female rats. On the other hand, testosterone significantly increased the total content of the phospholipid in the liver microsomes of both intact and gonadectomized male and female rats.

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