Properties of 5-ene-3 beta-hydroxysteroid dehydrogenase in granulosa tissue from the domestic fowl (Gallus domesticus).
Microsomal 5-ene-3 beta-hydroxysteroid dehydrogenase activity from fowl preovulatory granulosa tissue was solubilised by treatment with 2.0 M KCl. The efficiency of the solubilisation procedure was assessed by measuring the amount of activity remaining in the supernatant after centrifugation at 105,000 g for 8 h. The microsomal activity was resolved into two components: a fraction solubilised by the salt treatment and a fraction remaining membrane bound. The results indicate that the enzyme exists in two different environments within the membrane. The time course for the thermal inactivation of the microsomal enzyme supported this conclusion. The properties of the solubilised enzyme were compared with the untreated microsomal preparation, with respect to steroidal inhibition. Progesterone, 4-androstene-3,17-dione and oestradiol-17 beta all inhibited the enzyme and no difference was observed between the two preparations. The results are discussed in relation to the involvement of 5-ene-3 beta-hydroxysteroid dehydrogenase in the control of progesterone production in fowl granulosa tissue.
D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D005260:Female; D006107:Granulosa Cells / Q000201:enzymology*; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D011375:Progesterone Reductase / Q000378:metabolism*; D013256:Steroids / Q000494:pharmacology
D013256:Steroids; D015096:3-Hydroxysteroid Dehydrogenases; D011375:Progesterone Reductase