Immunohistochemical localization and biological activity of the steroidogenic enzyme cytochrome P450 17α‐hydroxylase/C17, 20‐lyase (P450_C17) in the frog brain and pituitary

Abstract

It is now clearly established that the brain has the capability of synthesizing various biologically active steroids including 17-hydroxypregnenolone (17OH-D 5 P), 17-hydroxyprogesterone (17OH-P), dehydroepiandrosterone (DHEA) and androstenedione (D 4 In the 1980s, Baulieu, Robel and co-workers discovered that the concentrations of pregnenolone (D 5 P), dehydroepiandrosterone (DHEA) and their sulfate esters pregnenolone-sulfate (D 5 PS) and dehydroepiandrosterone-sulfate (DHEAS) in the CNS remain elevated long after adrenalectomy and castration (Corpéchot et al. 1981(Corpéchot et al. , 1983, and they found that the circadian variations of these steroids in brain tissue are not synchronized with those of circulating steroids (Robel et al. 1986), suggesting that some steroids are actually produced in the CNS. Such steroids that are synthesized from cholesterol or other early precursors by nerve cells are collectively referred to as neurosteroids (Robel and Baulieu 1994).Several of the enzymes involved in steroidogenesis or the mRNAs encoding these enzymes have now been localized in

Brain steroid contents in the catfish Heteropneustes fossilis: sex and gonad stage-specific changes

“…Recent studies have revealed the existence of key enzymes in various mammalian and nonmammalian species such as P450scc (Tsutsui and Yamazaki 1995;London et al 2006), 3b-hydroxysteroid dehydrogenase (3b-HSD) (Sakamoto et al 2001), P450c17 (cytochrome P450 17a-hydroxylase/c17,20-lyase; Corpechot et al 1981;Do Rego et al 2007), 17b-hydroxysteroid dehydrogenase (17b-HSD) (Pelletier et al 1995;Zhou et al 2005), 5a-reductase (Saitoh et al 1982;Andersson et al 1991), P450 aromatase (Naftolin et al 1972(Naftolin et al , 1975Matsuoka et al 2006), sulfotransferase and sulfatase (Knapstein et al 1968;Strott 1996), 11b-HSD (Grosser and Axelrod 1968;Moisan et al 1990Moisan et al , 1992, and cytochrome P45011b (Ozaki et al 1991;Erdmann et al 1996). Callard et al (1978) published the first paper describing high aromatase and 5a-reductase activities, thus bringing teleost fish in the area of neurosteroid research.…”

Biosynthesis and Biological Actions of Pineal Neurosteroids in Domestic Birds

“…However, studies conducted over the past two decades have demonstrated that the central and peripheral nervous systems have the capacity of synthesizing steroids, the so-called ‘neurosteroids' [for reviews, see [1,2,3,4,5,6,7,8,9]. De novo formation of neurosteroids in the brain was originally demonstrated in mammals [10,11,12,13,14,15,16,17,18], and subsequently in birds [2,6,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35], amphibians [36,37,38,39,40,41,42,43,44,45,46,47] and fish [48,49,50,51]. Therefore, de novo synthesis of neurosteroids from cholesterol in the brain appears to be conserved across the subphylum vertebrata [1,2,3,4,5,6,7,8,9].…”

Induced synthesis of P450 Aromatase and 17β-estradiol by D-aspartate in frog brain

“…3-HSD and CYP17-ir have been reported in different parts of the brain, including the preoptic area and the hypothalamus. P450 C17 -ir cells are widely distributed in the telencephalon, diencephalon, mesencephalon and metencephalon (Do Rego et al, 2007;Do Rego et al, 2009b).…”