Androgen secreting adrenocortical tumours. (1/160)

BACKGROUND: Androgen secreting adrenocortical tumours are rare in children and the determination of their malignant potential can be difficult. OBJECTIVES: To assess the presentation, histology, and clinical behaviour of these tumours. SETTING: Two tertiary referral centres. STUDY DESIGN: Retrospective analysis of children diagnosed with an androgen secreting adrenocortical tumour between 1976 and 1996. PATIENTS: Twenty three girls and seven boys aged 0-14 years. RESULTS: Pubic hair was observed in all children, clitoromegaly or growth of the phallus in 23 children, acceleration of linear growth in 22 children, and advanced bone age (> 1.5 years) in 18 children. Hypersecretion of androgens was detected by assessment of serum androgen concentrations alone in four patients and by 24 hour urine steroid excretion profiles in 22 patients. All 16 tumours measuring < 5 cm in diameter were benign. Of the tumours measuring 5-9 cm, three were malignant and seven were benign, whereas all four tumours > 10 cm were malignant. Histological slides were available for reassessment in 25 children. Although mitoses and necrosis were more characteristic of tumours with malignant behaviour, no exclusive histological features of malignancy were seen. CONCLUSION: Histological criteria for malignancy are not reliable, whereas tumour size is important in assessing malignant potential.  (+info)

Identification by chimera formation and site-selected mutagenesis of a key amino acid residue involved in determining stereospecificity of guinea pig 3-hydroxysteroid sulfotransferase isoforms. (2/160)

The 3-hydroxysteroid sulfotransferases that have been isolated and cloned from humans and rodents appear to have broad substrate specificities. In the guinea pig, however, two 3-hydroxysteroid sulfotransferases have been isolated that function according to an innate stereospecificity: the alpha-isoform acts on steroids with a 3-hydroxyl group oriented in the alpha position, whereas the beta-isoform acts on steroids where the 3-hydroxyl group is in a beta orientation. To examine the structural basis for this remarkable stereoselectivity, chimeras of the two enzymes, which are 87% identical, were constructed. A chimera consisting of the NH(2)-terminal 91 amino acids of the alpha-isoform and the COOH-terminal 196 amino acids of the beta-isoform displayed activity similar to that of the alpha-isoform. Site-selected mutagenesis of this 3alpha/beta-hydroxysteroid sulfotransferase chimera involving the 12 amino acid differences that exist between the two isoforms within the 91 amino acid NH(2)-terminal region revealed that the amino acid residue at position 51 plays a fundamental role in determining the stereospecificity exhibited by the alpha- and beta-isoforms, i.e. if residue 51 is an asparagine, alpha activity predominates, whereas if an isoleucine is in that position, beta activity prevails.  (+info)

Dexamethasone-induced apoptosis of mouse thymocytes: prevention by native 7alpha-hydroxysteroids. (3/160)

Dehydroepiandrosterone (DHEA) has been shown to decrease the dexamethasone (DEX)-induced apoptosis of thymocytes and to be one of the native 3beta-hydroxysteroids extensively 7alpha-hydroxylated in thymus. This led us to question whether DHEA or 7alpha-hydroxy-DHEA is responsible for the decrease in DEX-induced apoptosis of thymocytes and whether this property is shared with other native 3beta-hydroxysteroids and their 7alpha-hydroxylated metabolites. Treatment of mice with DHEA or 7alpha-hydroxy-DHEA prior to DEX led to a smaller decrease in thymus weight than with DEX alone and to a disappearance of the DEX-induced changes in thymocyte phenotypes. Thymocyte apoptosis induced by DEX treatment was significantly lowered in DHEA- and 7alpha-hydroxy-DHEA-treated thymi, even after 18 h culture with additional 10-6 mol/L DEX. Extensive apoptosis of thymocytes cultured with 10-7 mol/L DEX was brought back to control levels when 10-5 mol/L 7alpha-hydroxy-DHEA or 10-5 mol/L 7alpha-hydroxy-epiandrosterone was added. After use of DHEA and epiandrosterone or pregnenolone, less significant and no significant changes were obtained, respectively. These findings imply that the 7alpha-hydroxylation of 3beta-hydroxysteroids may be a prerequisite for an exquisite regulation of the thymocyte-positive selection driven by the glucocorticoids produced in thymic epithelial cells.  (+info)

Hormone profiles in hormone-dependent cancers. (4/160)

Studies on the relationship of urinary excretion of androgen metabolites and estrogens to the natural history of breast cancer are reviewed. The importance of distinguishing between "within-population" studies (i.e., cancer patients versus normal controls) and "between populations" studies (i.e., low-risk versus high-risk populations) is emphasized, and it is pointed out that "qualitative" agreement (i.e. the same direction of differences) between the two types of studies must be present in order to implicate a hormonal parameter as a determinant of the natural history of breast cancer. For reasons detailed in this paper, it is concluded that the reported relationship of low urinary androgen metabolite excretion to increased risk of developing breast cancer and poor response to adrenalectomy or hypophysectomy and the validity of the "estriol hypothesis," namely, that a high urinary ratio of estriol to estrone-plus-estradiol in early life is protective against subsequent development of breast cancer, are both dubious. A new hypothesis concerning the relationship of estrogens to breast cancer risk is presented: "A period of of time, prior to age 30, during which the amount of biological availability of active estrogens' (i.e., estrone and estradiol) is diminished, protects against subsequent development of cancer." This hypothesis is shown to be compatible with the epidemiological and biochemical data. Reports concerning the influence of nutrition on endocrine parameters are reviewed. Inanition and obesity have been shown to alter steroid metabolism but it is not known whether nutritional "microdifferences" (i.e., differences between populations or individuals that are due to cultural, geographic, or socioeconomic factors, but that fall within the range of "normal" or adequate nutrition) can also alter steroid metabolism.  (+info)

Strain differences in rat liver (UDP-glucuronyltransferase activity towards androsterone. (5/160)

Male Donryu, Wistar King rats showed discontinuous variations in hepatic microsomal UDP-glucuronyltransferase activities towards androsterone, but not towards testosterone, bilirubin, phenolphthalein and 4-nitrophenol. Fresh microsomal fraction with a low transferase activity towards androsterone formed 0.049--0.080 nmole of glucuronide/min per mg of protein, whereas fresh microsomal fraction with a high transferase activity towards androsterone formed 0.335--0.557 nmol of glucuronide/min per mg of protein. The microsomal fraction with low enzyme activity towards androsterone was not stimulated by treatment with Triton X-100 or freezing and thawing. In contrast, male Long Evans and Sprague-Dawley rats did not exhibit such diversity.  (+info)

Lifestyle determinants of 5alpha-reductase metabolites in older African-American, white, and Asian-American men. (6/160)

Men with higher endogenous 5alpha-reductase activity may have higher prostate cancer risk. This hypothesis raises two questions: (a) Could racial differences in 5alpha-reductase activity explain the observed racial differences in prostate cancer risk? and (b) Could a man reduce his activity level by modifying his lifestyle? To address these questions, we measured two hormonal indices of 5alpha-reductase activity [serum levels of androstane-3alpha-17beta-diol glucuronide (3alpha-diol G) and androsterone glucuronide (AG)] in healthy, older African-American, white, and Asian-American men, who are at high, intermediate, and low prostate cancer risk, respectively. We also examined associations between these metabolite levels and such lifestyle characteristics as body size and physical activity as well as select aspects of medical history and family history of prostate cancer. Men included in this cross-sectional analysis (n = 1054) had served as control subjects in a population-based case-control study of prostate cancer we conducted in California, Hawaii, and Vancouver, Canada and provided information on certain personal attributes and donated blood between March 1990 and March 1992. In this study, concentrations of 3alpha-diol G declined significantly with age and increased significantly with body mass index. Mean levels of 3alpha-diol G, adjusted for age and body mass index, were 6.1 ng/ml in African-Americans, 6.9 ng/ml in whites and 4.8 ng/ml in Asian-Americans. These differences were statistically significant (African-Americans versus whites: P < 0.01; whites versus Asian-Americans: P < 0.001). Concentrations of AG decreased significantly with age, but only in whites, and were unrelated to any of the reported personal attributes. Mean levels of AG, adjusted for age, were 44.1 ng/ml in African-Americans, 44.9 ng/ml in whites, and 37.5 ng/ml in Asian-Americans (Asian-Americans versus whites, P < 0.001). In conclusion, older African-American and white men have similar levels of these two indices of 5alpha-reductase activity, and these levels are higher than those of older Asian-American men. This difference may be related to the lower prostate cancer risk in Asian-Americans.  (+info)

16alpha-bromoepiandrosterone, a dehydroepiandrosterone (DHEA) analogue, inhibits Plasmodium falciparum and Plasmodium berghei growth. (7/160)

Dehydroepiandrosterone (DHEA) and its analogue, 16alpha-bromoepiandrosterone (alpha-epi-Br), may have activity against viral and parasitic infections, including human immunodeficiency virus (HIV) and Cryptosporidium parvum. Therefore, we evaluated its antimalarial effects on Plasmodium falciparum and Plasmodium berghei. In vitro, chloroquine (CQ)-sensitive and resistant strains of P. falciparum parasitized red blood cells were incubated with escalating doses of alpha-epi-Br or CQ. In vivo, 62 rats were infected with P. berghei and treated with CQ or alpha-epi-Br. At the highest doses tested against a CQ-sensitive strain, parasitemias decreased from 25.4% in the saline control group to 4.3% and 4.8% in the alpha-epi-Br and CQ groups, respectively (P < 0.05). Against two CQ-resistant strains, parasitemias decreased from 22.3-28.8% and 24.8-30% in the CQ and saline groups, respectively, to 2.5-2.7% in the alpha-epi-Br groups (P = 0.003). In vivo, on Day 4, parasitemias decreased from 23% in the saline group to 9-12% and 12% in the in alpha-epi-Br and CQ groups, respectively (P < 0.05). These data demonstrate that alpha-epi-Br shows activity against CQ-sensitive and resistant strains of P. falciparum in vitro. At the doses tested against P. berghei in vivo in rats, alpha-epi-Br is comparable to CQ.  (+info)

Familial resemblance for free androgens and androgen glucuronides in sedentary black and white individuals: the HERITAGE Family Study. Health, Risk Factors, Exercise Training and Genetics. (8/160)

Familial correlation analyses were used to evaluate the familial aggregation of plasma androgens and androgen glucuronides (testosterone (TESTO), dihydrotestosterone (DHT), androstane-3 alpha,17 beta-diol glucuronide (3 alpha-DIOL-G), and androsterone glucuronide (ADT-G)) in 505 members of 99 white families and 296 members of 111 black families participating in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study. Each of these four measures was determined by RIA after separation of conjugated and unconjugated steroid using C18 column chromatography. All participants were sedentary prior to being including in this study. Significant spouse correlations, as well as parent-offspring and sibling correlations, were found for TESTO, DHT, 3 alpha-DIOL-G, and ADT-G in the white sample, suggesting that common familial environments and genes contribute to the familial resemblance. In the black sample, significant sibling and parent-offspring correlations were found for all four phenotypes, while the spouse correlation was marginally significant for 3 alpha-DIOL-G and not significant for TESTO, DHT, and ADT-G. The non-significance of spouse correlations in the black individuals may be due to the small number of spouse pairs. The maximal heritability estimates of TESTO, DHT, 3 alpha-DIOL-G, and ADT-G were 69%, 87%, 74%, and 56% for white individuals and 70%, 73%, 62%, and 48% for black individuals respectively. Sex differences in heritability estimates were found in the white individuals, but they were less dramatic in the black individuals. In conclusion, plasma levels of androgens and androgen glucuronides are highly heritable in both white individuals and black individuals. There are notable sex differences in the white individuals.  (+info)