Inactivating PAPSS2 mutations in a patient with premature pubarche

A heterodimer of human 3'-phospho-adenosine-5'-phosphosulphate (PAPS) synthases is a new sulphate activating complex

3'-Phospho-adenosine-5'-phosphosulphate (PAPS) synthases are fundamental to mammalian sulphate metabolism. These enzymes have recently been linked to a rising number of human diseases. Despite many studies, it is not yet understood how the mammalian PAPS synthases 1 and 2 interact with each other. We provide first evidence for heterodimerisation of these two enzymes by pull-down assays and Förster resonance energy transfer (FRET) measurements. Kinetics of dimer dissociation/association indicates that these heterodimers form as soon as PAPSS1 and -S2 encounter each other in solution. Affinity of the homo- and heterodimers were found to be in the low nanomolar range using anisotropy measurements employing proteins labelled with the fluorescent dye IAEDANS that--in spite of its low quantum yield--is well suited for anisotropy due to its large Stokes shift. Within its kinase domain, the PAPS synthase heterodimer displays similar substrate inhibition by adenosine-5'-phosphosulphate (APS) as the homodimers. Due to divergent catalytic efficacies of PAPSS1 and -S2, the heterodimer might be a way of regulating PAPS synthase function within mammalian cells.

46,XX DSD: the masculinised female

The 46,XX disorders of sex development (DSDs) cause virilisation or masculinisation of the female foetus. The final common pathway of all 46,XX DSDs is excess dihydrotestosterone (DHT) or potent foreign androgen in the genital tissue during the critical period of sexual differentiation. Whereas the foetal testis is source of androgen in the male, it is the foetal adrenal that produces the DHT precursors in the female. By understanding the principles of human steroid biosynthesis, the pathogenesis of each disorder may be logically deduced, and treatment strategies are rationally constructed. In practice, however, therapies for many of these diseases are fraught with complications and caveats, and current approaches leave much room for improvement. This review discusses these diseases, their pathogenesis and approaches to therapy. We emphasise areas where improved treatments are sorely needed.

Androgen replacement therapy in Turner syndrome: a pilot study

CONTEXT

Women with Turner syndrome (TS) have reduced levels of androgens due to ovarian failure.

HYPOTHESES

Morbidity associated with TS, such as bone fragility, metabolic changes, obesity, neurocognitive profile, and sexual problems may partly relate to androgen insufficiency and improve on androgen replacement therapy (ART).

OBJECTIVES

The objective of the study was to determine the effect of androgens on morbidity in TS.

DESIGN

Fourteen TS women (aged 17-27 yr) participated in a randomized, double-blind, placebo-controlled crossover pilot. The study was conducted in a hospital outpatient clinic between December 2001 and July 2004.

INTERVENTION

TS patients were on estrogen/progestin replacement therapy. Subjects received oral 1.5 mg methyl testosterone (ART) or placebo for 1 yr and the alternative for another year.

MAIN OUTCOME MEASURES

The study compared body composition as a primary outcome, and physiology, biochemistry, visceral fat, cognition, and quality of life (QOL) as secondary outcomes.

RESULTS

ART as compared with placebo reduced total cholesterol, triglycerides, and high-density lipoprotein cholesterol. It improved bone mineral density, increased lean body mass, and decreased fat mass. ART improved attention, reaction time, and verbal memory and had no effect on executive functions and spatial cognition. Patients reported improved QOL, including general health, coping with stress, and sexual desire.

CONCLUSIONS

Androgen insufficiency plays a role in TS-impaired body composition, neurocognition, and QOL, and these aspects improve with ART, which was safe and effective when given for 1 yr.

Diagnosis of diseases of steroid hormone production, metabolism and action

Biochemical tests have been the basis for investigations of disorders affecting steroid hormones. In recent years it has been possible however to study the genes that determine functional enzymes, cofactors, receptors, transcription factors and signaling systems that are involved in the process. Analyses of mutations are available as a diagnostic service for only a few of these genes although research laboratories may be able to provide a service. Both biochemical and genetic research have brought to light new disorders. Some genes for transcription factors involved in the development of the endocrine organs have also been identified and patients with defects in these processes have been found. This paper will review general aspects of adrenal disorders with emphasis on clinical and laboratory findings. As with all endocrine investigations there are few single measurements that provide a definitive answer to a diagnosis. Timing of samples in relation to age, gender and time of day needs to be considered.