Ergosterol derivatives exhibited copious promising biological activities. The fungus Gyromitra esculenta is widely distributed in Europe and North America. In order to examine the chemical properties of esculenta, a phytochemical study has been preceded resulted isolation steroid, ergosta-5, 22-dien-3β-ol (brassicasterol), from its methanol extract. complete identification absolute configuratio...

SYNOPSIS. Current risk assessment techniques for almost all chemicals involve establishing a threshold dose, or the dose below which no adverse effects are seen. But threshold doses may not apply in situations where the chemical mimics the actions of an endogenous compound—such as a steroid hormone—that is important to development. In such cases, any exposure may exceed the threshold. Recent st...

Estrogen signaling is critical in the progression of tumors that bear estrogen receptors. In most patients with breast cancer, inhibitors that block interactions of estrogen with its receptors or suppress the production of endogenous estrogens are important interventions in the clinic. Recent evidence now suggests that estrogen also contributes to the pathogenesis of non-small cell lung cancer ...

Aromatase is a member of the cytochrome P450 superfamily that catalyzes the conversion of androgens (C(19)), namely testosterone and androstenedione, into oestrogens (C(18)), oestradiol, and oestrone, respectively. The enzyme is active in various tissues in both females and males, thus oestrogens are produced not only in gonads but also in extra-gonadal localizations such as brain, adipose tiss...

A number of studies have been devoted to the analysis of the anatomical distribution, control by steroids and functional significance of aromatase (the enzyme metabolizing testosterone into 17beta-estradiol) in the quail brain. In particular, the sexually dimorphic nucleus preopticus medialis has been the main focus of investigation because testosterone aromatization in this structure mediates ...

I n t r o d u c t i o n Aromatase is the key enzyme in the synthesis of estrogens and catalyzes the conversion of androstenedione and testosterone into estrone and estradiol. Estrogens are known to be important in the growth of breast cancers in both preand postmenopausal women. In premenopausal women, the ovarian granulosa cells are the major sites of estrogen synthesis. Aromatization also occ...

The de novo production of estrone and estradiol by the fetal and infantile rat ovary and its regulation by cAMP, LH and FSH were investigated. Basal estrogen secretion was not demonstrable before d 5 after birth. However, the fetal ovary was responsive to cAMP as early as 14 d old. Estrone was the main estrogen secreted. Steroid aromatase inhibitors inhibited cAMP-stimulated estrone secretion. ...

Prostate cancer is a hormone-dependent cancer and its proliferation is stimulated by endogenous steroid hormones. Aromatase (CYP19) and 5a-reductase (SRD5A) are the key enzymes that synthesize these hormones. Aromatase converts androgens to estrogens and 5a-reductase converts testosterone to dihydrotestosterone. Natural compounds present in the Trichosanthes cucumerina L. delay prostate cancer ...

In recent years, there has been increasing recognition of the importance of steroid aromatization in organs besides the steroidogenic ones. Estrogens formed from C-19 precursors in peripheral tissues can clearly contribute to the levels of estrogens in the circulation, while aromatization in target cells may be an important determinant of the concentration of estrogens to which a particular pop...