Genetic and clinical spectrum of aromatase deficiency in infancy, childhood and adolescence.

INTRODUCTION: cP450aromatase deficiency provides clues for the understanding of the role of aromatase in prepubertal and pubertal human health and disease. Placental aromatization of androgens protects the female fetus against the virilizing action of fetal androgens. After birth, the dual effect of aromatase deficiency, excessive androgens, and insufficient estrogens is responsible for a variable clinical picture. Nineteen cases of aromatase gene (CYP19) deficiency have been reported. PHENOTYPE: Phenotype is dependent on sex and age. In newborns, aromatase deficiency should be considered in the etiology of 46,XX DSD, after ruling out congenital adrenal hyperplasia. In prepubertal aromatase deficient girls, high levels of ovarian androgens and gonadotropins facilitate the formation of ovarian cysts. Bone mineralization can be affected and bone aging is delayed. In pubertal girls, there is poor sexual development and abnormal virilization. The phenotype may be variable according to enzyme activity level. Insulin sensitivity may be abnormal in both men and women. Finally, aromatase might also play a role in the regulation of testicular cell mass in the newborn testis. CONCLUSION: Adequate interpretation of clinical data should lead to the analysis of the CYP19 gene for diagnostic confirmation and implementation of appropriate management.

Secretion of inhibin B by human prepubertal testicular cells in culture.

OBJECTIVE: Inhibin B is a secretory product of Sertoli cells of the human testis. It has been reported that serum levels of inhibin B in infant boys, peaking at 3 months of age, exceed levels in adult men. The aim of this study was to evaluate inhibin B secretion in primary prepubertal mixed testicular cell cultures, prepared from testes collected at necropsy. DESIGN AND METHODS: Cell cultures were divided into three age groups on the basis of differences in testicular histology: group 1 (n = 7), 1- to 10-day-old newborns, group 2 (n = 7), 1- to 9-month-old infants, and group 3 (n = 8), 12- to 84-month-old children. Cells were maintained in culture for 6 days, harvested and counted. In some samples, during the last 4 days, cells were stimulated with 10ng/ml highly purified human (h) LH (n = 9), 2 ng/ml recombinant human (rh) FSH (n = 9) or 50 ng/ml rhGH (n = 4). On day 6, the secretion of inhibin B and testosterone into the medium was estimated in triplicate. Inhibin B was determined by ELISA and testosterone by RIA. RESULTS: Median (range) inhibin B secretion was 465 (225-1007), 275 (107-298), and 58 (15-184) pg/million cells.24h in groups 1, 2 and 3 respectively. A logarithmic transformation of these values was performed to normalize data. Mean+/-s.d. of transformed inhibin B secretion in group 1 was significantly higher than in group 2 or 3 (P<0.005) and the values for groups 1 and 2 were significantly higher than that for group 3 (P< 0.005). No significant correlation between testosterone and inhibin B secretion into the medium was found when the 22 culture samples were analyzed as a whole. Inhibin B secretion was significantly increased after stimulation with highly purified hLH, rhFSH and rhGH (P < 0.05) and a significant positive correlation between inhibin B and testosterone was found under both hLH and rhFSH stimulation. CONCLUSIONS: It is concluded that cells collected from newborns have the highest capacity to secrete inhibin B in vitro, and that this capacity decreases with age during the first years of life. Since no data are available on serum inhibin levels in newborns, it is possible that concentrations at 3 months of age do not represent a post-natal peak but a declining level of high newborn values. As expected, FSH stimulated inhibin B secretion in culture. LH stimulation was probably mediated by paracrine factors secreted by interstitial cells. Finally, our results add new evidence of the involvement of GH in testicular maturation.

Expression of the aromatase gene in the human prepubertal testis.

It has been proposed that estrogens might play a negative feedback role in the local regulation of androgen biosynthesis in the testis. Although aromatase has been reported to be present in human adult Leydig cells, CYP19 gene expression in the human prepubertal testis has not been studied. Human prepubertal testicular tissue was obtained from 12 testes collected at necropsy. Ages ranged from 0.07 to 7 years, but 7 of the 12 subjects were younger than 3 months old. Tissue mRNA was subjected to RT-PCR analysis by two methods. Cytochrome P450arom mRNA was detected by non-radioactive RT-PCR in five of the 12 prepubertal testes collected from 0.05-7 year-old subjects, and in one testis collected from a 15 year-old pubertal control. Four of these five prepubertal samples belonged to the youngest infant group. Using a more sensitive, radioactive RT-PCR, aromatase mRNA was detected in all prepubertal testes. This study shows that the CYP19 gene is expressed in the prepubertal human testis including the period of early postnatal activation. It is possible that estrogens may have a role in prepubertal males during this period.

[Role of 3 beta hydroxysteroid dehydrogenase (3 beta HSD) in human adrenal androgen synthesis]. / Implicancias de la enzima 3 beta hidroxiesteroide dehidrogenasa (3 beta HSD) en la síntesis de andrógenos en la adrenal humana.

Adrenarche is the maturational increase of adrenal androgens that takes place in 6-8 year old children. In order to study the role of 3 beta HSD in the regulation of the synthesis of human adrenal androgens, the abundance of 3 beta HSD mRNA (Dot Blot and semiquantitative RT-PCR) was measured in 11 human prepubertal and early pubertal adrenal tissues. Subjects were divided in 2 age groups (Gr): Gr1, < 8 years (y) old (n = 6, range 0.1-2.5) and Gr2, > or = 8 y old (n = 5, range 8.0-13.0). Tissue from one adrenal tumor with Cushing's syndrome (TSC) and 2 virilizing adrenal tumors (TV), as well as adrenal cells prepared from the TSC and from 1 TV were also studied. They were maintained in culture for 3 days in basal conditions (BC) and under ACTH and IGF-1 stimulation. mRNA in Gr1 was higher than in Gr2 (Dot blot: 4.65 +/- 2.70 and 0.28 +/- 0.27 AU, p = 0.006; RT-PCR: 21.5 +/- 12.5 and 6.77 +/- 3.78 AU, p = 0.039, respectively). 3 beta HSD mRNA in TSC (8.74 +/- 1.74) was higher than in the 2 TVs (0.47 +/- 0.02 and 0.87 +/- 0.08) p = 0.001. In TSC cells, basal mRNA (0.82 +/- 0.10) decreased under ACTH (0.55 +/- 0.06), p = 0.005, and increased under IGF-1 (2.36 +/- 0.07), p = 0.006. No changes were observed in TV cells. On day 3, TV cells in BC secreted 1170.0 +/- 210.0 and 335.0 +/- 29.0 pmol/10(6) cells in 24 hs of DHEAS and androstenedione, while TSC cells secreted 17.1 +/- 3.5 and 73.7 +/- 11.7, respectively. Values increased under ACTH in TV cells (2006.0 +/- 360.0 and 525.0 +/- 76.0) and in TSC cells (29.8 +/- 5.4 and 366.8 +/- 129) p < 0.05, but they decreased under IGF-1 only in TSC cells (7.9 +/- 2.4 and 43.7 +/- 6.1) p < 0.05. These data support the hypothesis that human adrenarche could be secondary to a decrease of 3 beta HSD mRNA. Our finding that when 3 beta HSD mRNA decreases androgen secretion increases (ACTH) and when 3 beta HSD mRNA increases androgen secretion decreases (IGF-1), strongly suggests that 3 beta HSD has a modulatory role in adrenal androgen steroidogenesis.

Decrease in the expression of the 3beta-hydroxysteroid dehydrogenase gene in human adrenal tissue during prepuberty and early puberty: implications for the mechanism of adrenarche.

Adrenarche is the increase of adrenal androgen secretion, mainly dehydroepiandrosterone and dehydroepiandrosterone sulfate, that occurs during prepuberty in higher primates. This event takes place at about 6-8 y of age in humans. It had been postulated that adrenarche might reflect an increase in the 17,20 lyase:17OH-ase activity ratio of microsomal cytochrome P450c17. However, studies to demonstrate this mechanism have been unsuccessful. Because it has been described that virilizing adrenocortical carcinomas have high dehydroepiandrosterone sulfate secretion and low 3beta-hydroxysteroid dehydrogenase (3betaHSD) activity, in this study we evaluated the possible existence of maturative changes of the level of 3betaHSD type II mRNA in 11 normal prepubertal and early pubertal human adrenals. Adrenal glands from subjects aged 0.1 to 13 y were obtained from organ donors, patients undergoing resection of the kidney for renal neoplasms or necropsies with less than 6 h of postmortem time. The expression of 3betaHSD type II gene was studied by dot blot in all samples and by relative reverse transcriptase (RT)-PCR in nine samples. The size of the transcripts was evaluated by Northern blot. Hybridization was performed using labeled human 3betaHSD cDNA probes. The uniformity of loading was tested using labeled human beta actine cDNA. The relative intensities of hybridization signals were quantified by scanning densitometry. The expected bands after relative RT-PCR were eluted, and radioactivity was measured in a scintillation counter. For the analysis of the results, subjects were divided into two groups as a function of age: group 1, less than 8 y (n = 6; range 0.1-2.48 y) and group 2, equal or older than 8 y (n = 5; range 8-13 y). 3BetaHSD type II mRNA expression, analyzed by dot blot and relative RT-PCR, was significantly higher (p < 0.05) in group 1 (median and range 4.99, 0.50-8.00 and 16.3, 13.5-40.0 arbitrary units, respectively) than in group 2 (0.15, 0.12-0.75 and 5.66, 3.18-13.0, respectively). In conclusion, we have shown a decrease of the expression 3betaHSD type II gene as a function of age in prepubertal and early pubertal normal human adrenal tissue. This maturative change might be involved in the mechanism of human adrenarche.

Report of an XX male with hypospadias and pubertal gynecomastia, SRY gene negative in blood leukocytes but SRY gene positive in testicular cells.

Most XX male subjects present an anomalous translocation of the sex-determining region of the chromosome Y (SRY) gene from chromosome Y to chromosome X. Several explanations have been proposed for the differentiation of testicular tissue in the absence of SRY gene. A patient is presented in whom the SRY gene was absent in peripheral leukocytes but present in testicular tissue. This possibility should always be ruled out before diagnosing Y-negative XX maleness.