In order to determine the contribution of serum dehydroepiandrosterone sulfate (DS) to estrone (E1) production in normal women and the effect of chronic elevation of the serum DS concentration on DS metabolism, four normal women and four women with high endogenous serum DS were infused with [3H]DS and [14C]E1 or [14C]testosterone for 6 h. Blood samples were analyzed for radioactivity as DS, dehydroepiandrosterone (D), androstenedione, testosterone, and dihydrotestosterone. Urine was collected for analysis of creatinine, <em>17</em>-<em>ketosteroids</em> (<em>17</em>-KS), and radioactivity as estrone (E1). The serum DS of 12.4 +/- 1.44 mumol/L (mean +/- SE) in the group with high DS was higher than that of 3.96 +/- 1.0 mumol/L (1.46 +/- 0.37 micrograms/mL) in the normals (P less than 0.005). Those with high DS also had increased <em>17</em>-KS (13.2 +/- 2.0 vs. 5.68 +/- 0.68 mg/day, P less than 0.025) and a higher blood production rate of DS (PBDS) (126 +/- 21 (n = 3) vs. 54.3 +/- 13.8 mmol/day, P less than 0.05) but a lower MCRDS (10.94 +/- 0.61 (n = 3) vs. 13.8 +/- 0.27 L/day, P less than 0.01) than that in normals. In the four normal women the fraction of infused DS converted to estrone ( [rho]BMDS E1) was 0.00078 +/- 0.00018, the amount of E1 produced from serum DS was 41.3 +/- 15 nmol/day, the basal plasma E1 was 102 +/- 18 pmol/L, the MCRE1 was 1340 +/- 181 L/day, the value for blood production of E1 (PBE1) was 129 +/- 12 nmol/day, and the portion of E1 derived from DS was 30.4 +/- 9.4%. Correlation analysis of the data from these eight subjects showed that <em>17</em>-KS, PBDS, and the serum DS were all correlated with body surface area, body weight, and ponderal index and that <em>17</em>-KS excretion, PBDS, and serum DS were all correlated with one another. The most important predictors of <em>17</em>-KS excretion were serum DS (P less than 0.001) and the ponderal index (P less than 0.05).

<em>17</em> beta-Hydroxysteroid dehydrogenase (<em>17</em>HSD) type 2 efficiently catalyzes the conversion of the high activity <em>17</em> beta-hydroxy forms of sex steroids into less potent <em>17</em>-<em>ketosteroids</em>. In the present study in situ hybridization was utilized to analyze the cellular localization of <em>17</em>HSD type 2 expression in adult male and female mice. The data indicate that <em>17</em>HSD type 2 mRNA is expressed in several epithelial cell layers, including both absorptive and secretory epithelia as well as protective epithelium. In both males and females, strong expression of <em>17</em>HSD type 2 was particularly detected in epithelial cells of the gastrointestinal and urinary tracts. The mRNA was expressed in the stratified squamous epithelium of the esophagus, and surface epithelial cells of the stomach, small intestine and colon. The hepatocytes of the liver and the thick limbs of the loops of Henle in the kidneys, as well as the epithelium of the urinary bladder, also showed strong expression of <em>17</em>HSD type 2 mRNA in both male and female mice. In the genital tracts, low <em>17</em>HSD type 2 expression was detected in the seminiferous tubules, the uterine epithelial cells and the surface epithelium of the ovary. Expression of the mRNA was also detected in the sebaceous glands of the skin. The results indicate that in both male and female mice, <em>17</em>HSD type 2 is expressed mainly in the various epithelial cell types of the gastrointestinal and urinary tracts, and therefore suggest a role for the enzyme in steroid inactivation in a range of tissues and cell types not considered as classical sex steroid target tissues.

A series of variables involved in glucose handling were monitored before and after gastric bypass operation for morbid obesity. Blood glucose, insulin, C-peptide, gastric inhibitory polypeptide (GIP), pancreatic polypeptide (PP), and gastrin were measured basally and after an oral glucose load. Blood glucose, insulin, C-peptide, and PP were also measured after an intravenous glucose load. Adrenocortical function was evaluated by measuring plasma cortisol and urinary excretion of <em>17</em>-hydroxy-corticosteroids and <em>17</em>-<em>ketosteroids</em>. Nine subjects were examined before and 3 and 12 months after operation. Glucose tolerance improved postoperatively concomitant with decreased basal levels of C-peptide and insulin, increased hepatic insulin extraction, and evidence of reduced adrenocortical function. Parallel with reduced insulin resistance, support for an increase in both insulin secretion and removal was obtained postoperatively. It is concluded that the considerable endocrine abnormalities seen in morbid obesity can be normalized after gastric bypass operation and weight reduction.

<em>17</em> beta-Hydroxysteroid dehydrogenases (<em>17</em>HSDs) are enzymes catalyzing the conversion between <em>17</em> beta-hydroxy- and <em>17</em>-<em>ketosteroids</em>. Both estrogens and androgens possess their highest activity in the <em>17</em> beta-hydroxy form, and the enzymes, therefore, regulate the biological activity of sex hormones. In this study, we have characterized the complementary DNA (cDNA) for rat <em>17</em>HSD type 2. The cDNA encodes a protein with a predicted mol wt of 42,010 Da. The protein has 77% similarity and 62% identity with the human <em>17</em>HSD type 2 enzyme. Furthermore, the hydropathicity profiles of the enzymes are very similar. The two isozymes contain a putative transmembrane region close to the N-terminus. However, the rat isozyme lacks the two lysine-rich amino acid cluster present at the N- and C-terminals of human <em>17</em>HSD type 2. The tissue distribution of the rat <em>17</em>HSD type 1 and type 2 enzymes is very similar to that of the human enzymes. The highest expression of <em>17</em>HSD type 2 was detected in the placenta. In addition, a 1.5-kilobase messenger RNA for the enzyme was detected in the small intestine, liver, and kidney of both sexes. The two messenger RNAs for rat <em>17</em>HSD type 1 (1.4 and 1.7 kilobases) were highly expressed only in the ovary, and at very low concentrations in the kidney of both sexes. Transiently expressed rat <em>17</em>HSD type 2 showed oxidative activity almost exclusively in cultured human embryonic kidney 293 cells, converting estradiol into estrone and testosterone into androstenedione, whereas the opposite was observed for the rat type 1 enzyme. The data suggest that similarly to the corresponding human isoforms, rat <em>17</em>HSD type 2 is mostly involved in the oxidation of <em>17</em> beta-hydroxysteroids into their relatively inactive keto derivative in peripheral tissues, whereas rat <em>17</em>HSD type 1 is mainly involved in the glandular biosynthesis of estradiol.

Dehydroepiandrosterone and its sulphate are important factors for vitality, development and functions of the CNS. They were found to be subjects to a series of enzyme-mediated conversions within the rodent CNS. In the present study, we were able to demonstrate for the first time that membrane-associated dehydroepiandrosterone 7alpha-hydroxylase activity occurs within the human brain. The cytochrome P450 enzyme demonstrated a sharp pH optimum between 7.5 and 8.0 and a mean KM value of 5.4 micro m, corresponding with the presence of the oxysterol 7alpha-hydroxylase CYP7B1. Real-time RT-PCR analysis verified high levels of CYP7B1 mRNA expression in the human CNS. The additionally observed conversion of dehydroepiandrosterone via cytosolic 17beta-hydroxysteroid dehydrogenase activity could be ascribed to the activity of an enzyme with a broad pH optimum and an undetectably high KM value. Subsequent experiments with cerebral neocortex and subcortical white matter specimens revealed that 7alpha-hydroxylase activity is significantly higher in the cerebral neocortex than in the subcortical white matter (p < 0.0005), whereas in the subcortical white matter, 17beta-hydroxysteroid dehydrogenase activity is significantly higher than in the cerebral neocortex (p < 0.0005). No sex differences were observed. In conclusion, the high levels of CYP7B1 mRNA in brain tissue as well as in a variety of other tissues in combination with the ubiquitous presence of 7alpha-hydroxylase activity in the human temporal lobe led us to assume a neuroprotective function of the enzyme such as regulation of the immune response or counteracting the deleterious effects of neurotoxic glucocorticoids, rather than a distinct brain specific function such as neurostimulation or neuromodulation.

The enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) plays an essential role in the biosynthesis of all steroid hormones. We previously reported the isolation, characterization, and tissue-specific expression of four distinct but highly homologous 3 beta HSD cDNAs (forms I, II, III, and IV). Enzymatic characterization of three of these isoforms demonstrated that mouse 3 beta HSD I and III function as dehydrogenase/isomerases, but 3 beta HSD IV functions exclusively as a 3-<em>ketosteroid</em> reductase. We now report the isolation and characterization of an additional distinct mouse 3 beta HSD cDNA, 3 beta HSD V, which is expressed in the liver of male mice beginning in late puberty. Similar to 3 beta HSD IV, 3 beta HSD V functions exclusively as a 3-<em>ketosteroid</em> reductase converting an active androgen, dihydrotestosterone (DHT), into an inactive androgen, 5 alpha-androstane-3 beta,<em>17</em> beta-diol. Expressed 3 beta HSD V, however, exhibits a considerably lower apparent Michaelis-Menten constant (Km) value for DHT than 3 beta HSD IV (0.47 microM vs. 2.2 microM, respectively). The complete predicted amino acid sequence of 3 beta HSD II is also reported. The predicted amino acid sequence of mouse 3 beta HSD V reveals that this new form is more closely related to the 3-<em>ketosteroid</em> reductases, mouse 3 beta HSD IV and rat III (93 and 84% identity, respectively), than to the other rodent isoforms that share less than 75% identity.(ABSTRACT TRUNCATED AT 250 WORDS)

Fifty-two children, age 5-10, from acne-prone families, were studied for a period of 1 year to examine the interrelationship between sebum, acne, pubertal development, and urinary steroid excretion. In each of the subjects, 30 boys and 22 girls, the composition of forehead skin lipid was determined 4 times yearly by thin-layer chromatography, with measurement of triglycerides, diglycerides, free fatty acids, wax esters, squalene, cholesterol, and cholesterol esters. Twice yearly, examination was made of the presence or absence of acne, pubertal maturation and the 24-hour urinary excretion of testosterone as determined by radioimmunnoassay, and of total <em>17</em>-<em>ketosteroids</em>, dehydroepiandrosterone, androsterone, and etiocholanolone, as determined by paper chromatography. The relative amount of sebaceous lipids was positively correlated with age of the subjects (wax esters p less than .001, squalene p less than .05), as was the triglyceride-diglyceride component (p less than .05). No significant correlation was seen with the fatty acids. Acne, primarily comedonal, occurred in 27/52 subjects (15 girls, 12 boys) and was associated with higher sebum values. One-half of the children with acne had no signs of pubertal development. A significantly positive correlation was observed between the relative amount of sebaceous lipid and the urinary excretion of <em>17</em>-<em>ketosteroids</em>, androsterone, and etiocholanolone in both sexes, and of testosterone and dehydroepiandrosterone in boys. The development of acne in children is an early pubertal event, often evident before other signs of pubertal maturation, and it is associated with an increase in sebum and in the urinary excretion of androgenic steroids.

Reduction of <em>17</em>-<em>ketosteroids</em> is a biocatalytic process of economic significance for the production of steroid drugs. This reaction can be catalyzed by different microbial <em>17</em>beta-hydroxysteroid dehydrogenases (<em>17</em>beta-HSD), like the <em>17</em>beta-HSD activity of Saccharomyces cerevisiae, Pichia faranosa and Mycobacterium sp., and by purified 3beta,<em>17</em>beta-HSD from Pseudomonas testosteroni. In addition to the bacterial 3beta,<em>17</em>beta-HSD the <em>17</em>beta-HSD of the filamentous fungus Cochliobolus lunatus is the only microbial <em>17</em>beta-HSD that has been expressed as a recombinant protein and fully characterized. On the basis of its modeled 3D structure, we selected several positions for the replacement of amino acids by site-directed mutagenesis to change substrate specificity, alter coenzyme requirements, and improve overall catalytic activity. Replacement of Val161 and Tyr212 in the substrate-binding region by Gly and Ala, respectively, increased the initial rates for the conversion of androstenedione to testosterone. Replacement of Tyr49 within the coenzyme binding site by Asp changed the coenzyme specificity of the enzyme. This latter mutant can convert the steroids not only in the presence of NADP(+) and NADPH, but also in the presence of NADH and NAD(+). The replacement of His164, located in the non-flexible part of the 'lid' covering the active center resulted in a conformation of the enzyme that possessed a higher catalytic activity.

In the adrenal gland cholesterol for steroid biosynthesis is derived from both de novo biosynthesis and receptor mediated uptake of plasma low density lipoproteins (LDL). In the present study we have compared ACTH stimulated adrenal production of cortisol in four control subjects and one adult male patient with abetalipoproteinemia, a disorder in which LDL is absent. Basal morning cortisol levels in the plasma in the control subjects (13.3 +/- 1.6 microgram/dl) and abetalipoproteinemic patient (14.6 micrograms/dl) were similar. During infusion of alpha 1, 24 ACTH however, plasma cortisol levels were higher in the control subjects than in the abetalipoproteinemic patient and this difference was significant at times after 4 hours. Urinary excretion of both <em>17</em>-hydroxy and <em>17</em>-<em>ketosteroids</em> over the 24 hour infusion period was also significantly lower in the abetalipoproteinemia patient indicating that cortisol production rates were reduced. Our results suggest that in the absence of plasma low density lipoproteins, as occurs in abetalipoproteinemia, the maximal production of adrenal corticosteroids is impaired. By inference, these findings lend in vivo support to the view that plasma low density lipoproteins serve as an important source of cholesterol for adrenal steroidogenesis in man.

Serum concentrations of dehydroepiandrosterone sulfate (DHEAS) were measured in 28 patients (18 females, 10 males) with congenital adrenal hyperplasia due to 21-hydroxylase deficiency who were treated with oral hydrocortisone (non-salt losers) or hydrocortisone and 9-alpha-fluorohydrocortisone (salt-losers). Adequacy of therapy was assessed by clinical findings, determination of bone age, urinary excretion of <em>17</em>-<em>ketosteroids</em>, and serum concentration of <em>17</em>-hydroxyprogesterone. These allowed the separation of patients into three groups: poorly controlled, adequately controlled and overtreated. Individual values for serum levels of DHEAS were compared to mean normal values for age. In the adequately controlled and overtreated patients, mean serum concentrations of DHEAS were significantly lower than normal values for age (P less than 0.05). In the poorly treated patients, the mean serum concentration of DHEAS was not significantly different from normal values for age (P = 0.50). These data indicate that the serum concentration of DHEAS is overly suppressed in treated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. This finding suggests that measurement of the serum levels of DHEAS has limited value in assessing the adequacy of therapy in this disease.

Human aldo-keto reductases 1C1-1C4 (AKR1C1-AKR1C4) function in vivo as 3-keto-, <em>17</em>-keto-, and 20-<em>ketosteroid</em> reductases and regulate the activity of androgens, estrogens, and progesterone and the occupancy and transactivation of their corresponding receptors. Aberrant expression and action of AKR1C enzymes can lead to different pathophysiological conditions. AKR1C enzymes thus represent important targets for development of new drugs. We performed a virtual high-throughput screen of a fragment library that was followed by biochemical evaluation on AKR1C1-AKR1C4 enzymes. Twenty-four structurally diverse compounds were discovered with low μM K(i) values for AKR1C1, AKR1C3, or both. Two structural series included the salicylates and the N-phenylanthranilic acids, and additionally a series of inhibitors with completely novel scaffolds was discovered. Two of the best selective AKR1C3 inhibitors had K(i) values of 0.1 and 2.7 μM, exceeding expected activity for fragments. The compounds identified represent an excellent starting point for further hit-to-lead development.

A 53-year-old woman presented with hirsutism of long duration and virilization of recent onset. She was gravida 12 para 9. The <em>17</em>-<em>ketosteroids</em> were normal, gonadotropins were in the post-menopausal range, and the serum testosterone was in the male range. After bilateral oophorectomy, the testosterone became normal. Ovarian pathology revealed stromal hyperthecosis.

To evaluate differences in the expression of cystic fibrosis (CF) transport defects in the gastrointestinal tract of subjects with CF, in vivo measurements of colonic and esophageal transepithelial electrical potential difference (PD) were performed before and during amiloride superfusion in CF and healthy subjects. Esophageal PD before (-16 +/- 2 vs. -16 +/- 3 mV) and after (-14 +/- 2 vs. -15 +/- 0.3 mV) superfusion with amiloride were similar for CF and healthy subjects. Basal rectosigmoid colon PD was also similar (CF: mean -23 +/- 6 and maximal -37 +/- 9 mV; normal: mean -26 +/- 5 and maximal -45 +/- 11 mV) in both groups. However, with amiloride superfusion (10(-4) M) the colonic PD in CF subjects was almost abolished (95% +/- 15% inhibition), whereas the PD in healthy subjects was only partially reduced (42% +/- 6%) (p less than 0.05). The greater inhibition with amiloride in CF, which was evident in absolute terms (26 +/- 4 vs. 16 +/- 3 mV for controls, p less than 0.05) as well as relative terms, could not be ascribed to a difference in mineralocorticoid secretion rates, because 24-h urine excretion of aldosterone and <em>17</em> hydroxy and <em>17</em> <em>ketosteroids</em> were similar in both groups. Freshly excised colonic epithelia from 1 CF and 3 non-CF subjects were studied in Ussing chambers, and a similar difference in amiloride responsiveness noted: PD and short-circuit current declined 33% +/- 2% and 37% +/- 4%, respectively, in seven tissues from the colons of 3 patients without CF, whereas both PD and short-circuit current were fully inhibited (100%) in all three tissues from the CF patient. As the presence of an amiloride-insensitive component of short-circuit current in non-CF colon is largely due to electrogenic Cl- secretion, the demonstration that this component was absent both in vivo and in vitro in CF colon establishes the presence of a defect in electrolyte transport in CF colon, a defect consistent with recent reports of absent electrogenic Cl- secretion in CF intestine.