Characterization and measurement of dehydroepiandrosterone sulfate in rat brain.

Abstract

Dehydroepiandrosterone (3f3-hydroxy-5-androsten-17-one, I) sulfate (Ia) has been characterized in the anterior and the posterior parts of the brain of adult male rats. Its level (1.58 ± 0.14 and 4.89 ± 1.06 ng/g, mean ± SD, in anterior and posterior brain, respectively) largely exceeded that of I in brain (0.42 ± 0.10 and 0.12 ± 0.03 ng/g in anterior and posterior brain, respectively) and of Ia in plasma (0.26 ± 0.13 ng/ml). Brain Ia level did not seem to depend on adrenal secretion; it was unchanged after administration of corticotropin or dexamethasone for 3 days, and no meaningful change occurred in brain 15 days after adrenalectomy plus orchiectomy, compared with sham-operated controls. In contrast, stress conditions prevailing 2 days after adrenalectomy plus orchiectomy or after the corresponding sham operation resulted in a significantly increased concentration of Ia in the brain. Changes of Ia level in brain occurred irrespective of changes in corresponding plasma samples. It is proposed that Ia formation or accumulation (or both) in the rat brain depends on in situ mechanisms unrelated to the peripheral endocrine gland system. Dehydroepiandrosterone (3,3hydroxy-5-androsten-17-one, I) sulfate (Ia) is below detection limit in the plasma of most adult mammals (1); the exceptions are man and the highest nonhuman primates (1-3). It is a major secretory product ofhuman adrenals (4-7), and its concentration in adult plasma is larger than that of any other steroid. Although Ia is the main precursor of placental estrogens (8-10) and is occasionally converted into active androgens in peripheral tissues (11,12) was added to 2 ml of plasma or <1 g of tissue, and then 5 ml ofacetone/ethanol (1:1) was added. Tissues were homogenized in acetone/ethanol (1:1) with a Teflon/glass homogenizer and sonicated with a Branson Jl sonifier equipped with a minitip at a 100-W setting for 10 sec. The suspensions were kept at 390C overnight and centrifuged at 1000 x g for 10 min. The supernatant was saved, and the pellet was extracted with 4 ml of methanol/chloroform (1:1) with continuous shaking at room temperature for 30 min. The extract was centrifuged, and the two supernatants were combined and taken to dryness. The residue was dissolved in 4 ml of methanol/chloroform (1:1)/10 mM NaCl and deposited on a Sephadex LH-20 column (10 X 445 mm) equilibrated and developed in the same solvent system (15). The first 50 ml to run off contained unconjugated I, Ia was eluted in the next 75 ml. It was completely separated from free I and from I conjugated to fatty acids (16) 4704The publication costs ofthis article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.

The Cholesterol Side‐Chain Cleavage Complex in Human Brain White Matter

“…The values for P, D and their sulfate esters are much higher than those of the sex steroids in all areas of the brain and in the same range as those reported in the rat (1,2). The values for unconjugated P and D are much higher than their respective values in plasma.…”

“…Two A5-3P-hydroxysteroid metabolites of cholesterol, pregnenolone (P) and deliydroepiandrosterone (D), have been detected in the brain of several mammalian species (rat, mouse, monkey and occasionally pig and man) (1)(2)(3). Definitive identification of the steroid moiety was made in rat brain extracts by gas/liquid chromatography-mass spectrometry (1, 2).…”

Functional significance of the rapid regulation of brain estrogen action: Where do the estrogens come from?

“…Several studies also suggest that androgen precursors, such as DHEA (dehydroepiandrosterone), and androgens are also produced de novo in the brain [68,147,161,164,246]. These steroids could thus also act as a substrate for aromatase.…”

An Essential Component in Steroid Synthesis, the Steroidogenic Acute Regulatory Protein, Is Expressed in Discrete Regions of the Brain

“…The essential function of StAR in steroidogenesis is established for all tissues that synthesize steroid, except for the human placenta and the brain. The brain synthesizes neurosteroids de novo, especially within glia (Corpechot et al, 1981;Koenig et al, 1995;Zwain and Yen, 1999;Compagnone and Mellon, 2000;Tsutsui et al, 2000), but the relative roles of locally produced neuroactive steroids and those converted from circulating precursors remain to be defined. Alterations in levels of locally produced neurosteroids in the hypothalamus, hippocampus, and other regions may serve as crucial paracrine modulators of essential brain functions, including sexual drive, learning, and memory (Majewska et al, 1986;Genazzani et al, 1995;Frye et al, 1996;Calogero et al, 1998;Akwa et al, 2001).…”