Aromatase cytochrome P-450, which catalyzes the conversion of androgens to estrogens, was purified from human placental microsomes. The enzyme was extracted with sodium cholate, fractionated by ammonium sulfate precipitation, and subjected to column chromatography in the presence of its substrate, androstenedione, and the nonionic detergent, Nonidet P-40. The preparation exhibits a single major...

Aromatase is a key enzyme involved in estradiol and estrone biosynthesis. Given that polymorphisms of the CYP19A1 gene encoding aromatase have been correlated with plasma testosterone levels, CYP19A1 may therefore act as a genetic modifier of the hyperandrogenic phenotype of polycystic ovary syndrome (PCOS). However, no functional CYP19A1 polymorphisms that predict the risk of PCOS have been id...

A puberal change in the secretory pattern of androgen was investigated in the rat. Using immature and adult rats which received an acute human chorionic gonadotrophin(HCG) stimulation, androstenedione and testosterone were measured both in the testicular venous blood(TVB) and in the testis by means of gaschromatography after preliminary separation by paperchromatography. In contrast to the adul...

Aromatase, a cytochrome P450, catalyzes the formation of aromatic C-18 estrogenic steroids from C-19 androgens. Four mutants of human aromatase have been expressed in Chinese hamster ovary cells using a stable expression method. The activities of these mutants were determined using [1 beta,2 beta-3H]androstenedione, [19-14C]androstenedione, and [1 beta,2 beta-3H]testosterone as substrates. The ...

On March 11, 2004, the Food and Drug Administration (FDA) pronounced that dietary supplement products containing androstenedione were adulterated new dietary ingredients under the Dietary Supplement Health and Education Act of 1994 (DSHEA). The FDA issued a press release, held a news conference, and sent warning letters to 23 companies that had manufactured, marketed or distributed the products...

The search of new substrates with pharmaceutical and industrial potential for biocatalysts including cytochrome P450 enzymes is always challenging. Cytochrome P450 BM3 mutant 139-3, a versatile biocatalyst, exhibited hydroxylation activities towards fatty acids and alkanes. However, there were limited reports about its hydroxylation activity towards steroids. Herein, an Escherichia coli-based w...

Cytochrome P-450-dependent 6 beta-hydroxylation of bile acids in rat liver contributes to the synthesis of the quantitatively important pool of 6-hydroxylated bile acids, as well as to the detoxification of hydrophobic bile acids. The lithocholic acid 6 beta-hydroxylation reaction was investigated and compared with androstenedione 6 beta-hydroxylation. Differential responses of these two activi...

This study investigated the age related variations in luteinizing hormone (LH), androstenedione, testosterone, and total estrogens response to exogenous gonadotropin-releasing hormone (GnRH) in Holstein-Friesian (HF) × Tharparkar bull calves. Fifteen bull calves were selected and, based on their age, were divided into Group I (14-16 months, n = 5), Group II (9-12 months, n = 5), and Group III (...

Recent measurements of circulating inhibin A and inhibin B concentrations indicate that inhibin B may play an important role in the selection of dominant follicles. The concentrations of inhibin A, inhibin B and activin A were measured in the follicular fluids of 61 individual follicles (4.8-20 mm in diameter) from 47 regularly cycling women using specific two-site enzyme-linked immunosorbent a...

OBJECTIVE To evaluate the placental activity of steroid sulfatase (STS), 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD-1) and P450 aromatase (P450arom) in polycystic ovarian syndrome (PCOS) compared to normal pregnant women. DESIGN Twenty pregnant women with PCOS and 30 control pregnant women who delivered at term were studied. Samples of placental tissue and cord blood were obtained after d...