Serum levels of 5-androstene-3 beta,17 beta-diol sulphate, 5 alpha-androstane-3 alpha, 17beta-diol sulphate and glucuronide, in late onset 21-hydroxylase deficiency

Sex hormone-binding globulin in congenital adrenal hyperplasia

BACKGROUND

Sex hormone-binding globulin biosynthesis is influenced by three hormonal systems: gonadal, insular and thyroid. Congenital adrenal hyperplasia is characterized by overproduction of adrenal androgens associated with impaired insulin sensitivity, hyperinsulinemia and often also with hypothyroidism. Only scarce data are available concerning congenital adrenal hyperplasia. The objective of this study was to determine the distribution of sex hormone-binding globulin and free testosterone levels in these patients and to what extent these values correlate with actual 17-hydroxyprogesterone and androstenedione levels, which are commonly used for monitoring of treatment effectiveness.

MATERIALS AND METHODS

A total of 300 retrospective laboratory records of 78 males and boys and 456 records of 162 girls and premenopausal women with diagnosis of congenital adrenal hyperplasia under common substitution treatment were evaluated statistically. The data were divided artificially into groups of low, normal and high levels, with respect to physiological concentrations for each sex and age. The percentages of the total in each group were calculated.

RESULTS

Whereas an almost Gaussian distribution occurred for males, the data for females displayed a considerable shift to low sex hormone-binding globulin and accordingly high free testosterone levels. Sex hormone-binding globulin levels did not correlate with 17-hydroxyprogesterone.

CONCLUSION

Low sex hormone-binding globulin levels in congenital adrenal hyperplasia, at least in females, reflect their involvement in insular and eventually thyroid axes, rather than the effectiveness of substitution.

The steroid metabolome of adrenarche

Adrenarche is an endocrine developmental process whereby humans and select nonhuman primates increase adrenal output of a series of steroids, especially DHEA and DHEAS. The timing of adrenarche varies among primates, but in humans serum levels of DHEAS are seen to increase at around 6 years of age. This phenomenon corresponds with the development and expansion of the zona reticularis of the adrenal gland. The physiological phenomena that trigger the onset of adrenarche are still unknown; however, the biochemical pathways leading to this event have been elucidated in detail. There are numerous reviews examining the process of adrenarche, most of which have focused on the changes within the adrenal as well as the phenotypic results of adrenarche. This article reviews the recent and past studies that show the breadth of changes in the circulating steroid metabolome that occur during the process of adrenarche.

Carbohydrate complexity and proportions of serum FSH isoforms in the male: lectin-based studies

FSH is synthesized and secreted in multiple molecular forms with different oligosaccharide structures which are needed for full expression of biological activity. GnRH and sex steroids modulate oligosaccharide structure and composition. In the present study we have assessed the carbohydrate complexity and proportion of circulating FSH isoforms during puberty, aging and after androgen administration to pubertal anorchid boys. Preparative isoelectrofocusing and lectin chromatography were used to isolate FSH isoforms on the basis of charge and internal carbohydrate complexity. Differences in sialic acid content and a progressive increase of isoforms bearing highly branched oligosaccharides were found during puberty. Less acidic, more bioactive FSH isoforms, secreted at mid-puberty may modulate important maturational events in the Sertoli cell population. Androgen administration to pubertal anorchid boys favoured the secretion of this type of isoforms. In adult men, the predominance of FSH isoforms bearing complex type oligosaccharides remained unchanged until very advanced age. These results show that the predominance of FSH isoforms bearing fully processed oligosaccharides in circulation may contribute to the development and maintenance of seminiferous epithelium function in men.

Simultaneous determination of androstenediol 3-sulfate and dehydroepiandrosterone sulfate in human serum using isotope diluted liquid chromatography–electrospray ionization-mass spectrometry

A simple method for simultaneous determination of androstenediol 3-sulfate (Adiol-3S) and dehydroepiandrosterone sulfate (DHEA-S) in human serum using isotope diluted liquid chromatography-electrospray ionization-ion trap-mass spectrometry (LC-ESI-ion trap-MS) was developed. After addition of deuterated internal standards ([2H5]Adiol-3S and [2H4]DHEA-S), human serum (100 microl) was deproteinized with acetonitrile and then applied to a solid-phase extraction cartridge, Oasis HLB. The obtained steroid sulfates fraction was washed with hexane and then analyzed by LC-ESI-MS operated in the negative ion mode. The quantification ranges of Adiol-3S and DHEA-S were 10-400 ng/ml and 0.05-8 microg/ml, respectively. The method does not require the chemical or enzymatic hydrolysis of the conjugates and purification with high-performance liquid chromatography, and shows satisfactory reproducibility and accuracy. The concentrations of these sulfates in the sera of healthy male volunteers (n=14) were 19.2-245.3 mg/ml (Adiol-3S) and 0.175-5.16 microg/ml (DHEA-S), and those of patients with prostate cancer (n=19) were 15.3-182.7 ng/ml (Adiol-3S; four samples, not detectable) and 0.110-2.421 microg/ml (DHEA-S).

Characterization of serum SHBG isoforms in prepubertal and pubertal girls

OBJECTIVE

SHBG is a circulating glycoprotein that binds dihydrotestosterone, testosterone and oestradiol with high affinity and low capacity. In girls, serum concentrations of SHBG gradually decrease with age due to a true fall in concentration and not to a change in the binding characteristics. The aim of our study was to determine the pattern of serum SHBG isoforms in normal girls in early childhood (ECh), late childhood (LCh) and puberty (P).

SUBJECTS

Fifteen normal girls were studied. They were divided into three groups according to their age: ECh: 3.7 +/- 0.9 years (mean +/- SD, n = 5); LCh: 6.4 +/- 0.5 years (n = 5); and P: 13.4 +/- 1.5 years (n = 5).

METHODS AND MEASUREMENTS

Preparative isoelectric focusing was used to isolate SHBG isoforms according to their isoelectric point (pI). Three groups of isoforms were isolated: SI: pI 5.2-5.4; SII: pI 5.4-5.6 and SIII: pI 5.6-5.8. Steroid levels in serum were determined by RIA.

RESULTS

The relative distribution of SHBG isoforms (% of the total SHBG recovered, mean +/- SD) in the three groups of girls studied was: ECh: SI: 25.8 +/- 9.9, SII: 53 +/- 10.5 and SIII: 21.2 +/- 1.6; LCh: SI: 8.8 +/- 3.1, SII: 58.8 +/- 12.2 and SIII: 31.8 +/- 8.6; P: SI: non-detectable; SII: 51.6 +/- 12.6 and SIII: 48.4 +/- 12.6.

CONCLUSION

These results indicate that serum SHBG is more heterogeneous before puberty. A considerable proportion of acidic isoforms are present early in life; they decrease during the prepubertal period and disappear when sexual development is completed. After puberty the glycoprotein is more homogeneous and an important proportion of more basic isoforms is present. At puberty serum SHBG not only falls in concentration but also has an altered sialic acid content which modulates its circulating half-life.

Steroid UDP glucuronosyltransferases

The glucuronidation of steroids is a major process necessary for their elimination in the bile and urine. In general, steroid glucuronides are biologically less reactive than their parent steroids. However, in some cases often associated with disease and steroid therapy, more reactive or toxic glucuronides may be formed. The concentrations of specific steroid glucuronides in the blood may also indicate hormonal imbalances and may funnction as diagnostic markers of genetic defects in steroid synthesis and metabolism. In this review, the forms of UDP glucuronosyltransferase involved in steroid glucuronidation are described in terms of their specificities, functional domains and regulation. The available evidence suggests that steroid glucuronidation is mainly carried out by members of the UGT2B subfamily which are encoded by genes containing 6 exons. Members of this subfamily exhibit a regioselectively in their glucuronidation of steroids that is mediated by domains in the amino-terminal half on the protein encoded by exons 1 and 2. Although much of this review will describe studies in the rat, preliminary evidence indicates that a similar situation may exist in humans.