5 beta- and 5 alpha-reductases for 4-ene-3-ketosteroids in golden hamster ovaries at different stages of development.
Ovarian homogenates from 10-, 23- 128- and 60-day-old golden hamsters were incubated with [14C]-4-androstene-3,17-dione or [7-3H]-progesterone in the presence of NADPH and enzyme activities and metabolism of progesterone were estimated. A rapid increase in uterine weight was found around 28 days of age. The activity of 5 alpha-reductase was very high in the ovaries of 23-day-old hamsters (647 +/- 117 (SD) nmol/g tissue/h), high in those of 28-day-old hamsters (135 +/- 4) and low in those of 10- and 60-day-old animals (20 +/- 16, 39 +/- 11). However, the activity of 5 beta-reductase was high in all ovaries of golden hamsters at different stages of development (84-132 nmol/g tissue/h). The major C-21-17-hydroxysteroids and C19-steroids formed from progesterone by the ovaries of 23-day-old hamsters were 5 alpha-steroids such as 3 alpha, 17-dihydroxy-5 alpha-pregnan-20-one and androsterone, whereas those by the ovaries of 28- and 60-day-old hamsters were 4-ene-3-ketosteroids and 5 beta- and 5 alpha-steroids such as 17-hydroxy-4-pregnene-3,20-dione. 3 alpha, 17-dihydroxy-5 alpha- and 5 beta-pregnan-20-one, 4-androstene-3,17-dione, testosterone and androsterone. The formation of oestradiol-17 beta and oestrone from progesterone was found only in the ovaries of 38- and 60-day-old hamsters. These results show that similarly high levels of 5 beta-reductase are present in all ovaries from suckling, immature and adult golden hamsters and that high levels of 5 alpha-reductase are formed only in ovaries from immature hamsters, especially those with small uterus. The active 5 alpha-reduction of 4-ene-3-ketosteroids may be responsible for the decrease in the formation of oestrogens in immature hamster ovaries.
D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism*; D000367:Age Factors; D000818:Animals; D006224:Cricetinae; D005260:Female; D008647:Mesocricetus; D010053:Ovary / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism; D012741:Sexual Maturation; D014599:Uterus / Q000033:anatomy & histology
D011374:Progesterone; D010088:Oxidoreductases; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; C021936:3-oxo-5 beta-steroid delta 4-dehydrogenase