Molecular biology of sex differentiation

Androgen receptor positively regulates gonadotropin-releasing hormone receptor in pituitary gonadotropes

Within pituitary gonadotropes, the gonadotropin-releasing hormone receptor (GnRHR) receives hypothalamic input from GnRH neurons that is critical for reproduction. Previous studies have suggested that androgens may regulate GnRHR, although the mechanisms remain unknown. In this study, we demonstrated that androgens positively regulate Gnrhr mRNA in mice. We then investigated the effects of androgens and androgen receptor (AR) on Gnrhr promoter activity in immortalized mouse LβT2 cells, which represent mature gonadotropes. We found that AR positively regulates the Gnrhr proximal promoter, and that this effect requires a hormone response element (HRE) half site at -159/-153 relative to the transcription start site. We also identified nonconsensus, full-length HREs at -499/-484 and -159/-144, which are both positively regulated by androgens on a heterologous promoter. Furthermore, AR associates with the Gnrhr promoter in ChIP. Altogether, we report that GnRHR is positively regulated by androgens through recruitment of AR to the Gnrhr proximal promoter.

Genetic aspects of ambiguous genitalia

The unexpected arrival of an infant with ambiguous genitalia is stressful for both physicians and parents. Careful assessment of the external genital structures and the overall infant directs the immediate management. Investigations include evaluation of glucose, electrolytes, chromosomes, and 17-ketosteroids as well as ultrasound and evaluation of the urinary tract as appropriate. The review of family and pregnancy history addresses concerns regarding medications or previously affected infants. The most efficient method of evaluating such an infant is by a team approach, with each team member contributing expertise and one communicating with the family and the family physician. Unnecessary overlap of investigations can be avoided as well as rash decisions as to sex of rearing. Counseling the family provides support during the stressful first days until decisions can be made about information regarding the diagnosis and prognosis of the infant, recurrence risk figures for subsequent pregnancies or other family members, and whether prenatal diagnosis might be appropriate. The family can be helped to move through the ordeal with their child and develop trust in the team members.

Cystic fibrosis presenting in a 45-year-old man with infertility

Cystic fibrosis commonly is regarded as a disease of childhood associated with severe pulmonary and pancreatic pathological conditions. We report on a previously healthy 45-year-old man who was diagnosed as having cystic fibrosis after presentation with primary azoospermia. The literature is reviewed. Although references are made to late presentations of cystic fibrosis none was found in which the initial complaint was infertility. Primary azoospermia may be the presenting manifestation of cystic fibrosis in the absence of major respiratory symptoms.

Persistence of Müllerian ducts in male pseudohermaphroditism, and its relationship to cryptorchidism

Twenty-two cases of male pseudohermaphroditism with persistence of Müllerian duct derivatives were reviewed. In 12 cases of mixed gonadal dysgenesis and five cases of dysgenetic male pseudohermaphroditism, testosterone-dependent steps of sex differentiation were also impaired, and testicular dysgenesis was prominent, even in the younger age group. The capacity of testes to inhibit the ipsilateral Müllerian duct was correlated with testicular descent: it is suggested that testicular dysgenesis explains both the functional and topographical testicular abnormalities observed in these male pseudohermaphrodites. Five other patients were cryptorchid but externally normally virilised, persistence of Müllerian derivatives representing their only abnormality of sex differentiation. Testicular structure was usually normal or showed changes attributable to long-standing cryptorchidism. It is suggested that in these patients, persistence of Müllerian derivatives is due to an inborn error of metabolism, affecting the binding of anti-Müllerian hormone to its receptor and that failure of testicular descent is caused by mechanical restraint by the abdominal Müllerian organs.

A complete form of testicular feminisation syndrome; a light and electron microscopy study

A case is described of testicular feminisation syndrome in a 19-yr-old patient with a normal female appearance. A laparotomy with removal of the gonads was performed. The latter looked like testes with intraparenchymal nodules. Light and electron microscopy study of these nodules revealed the presence of immature seminiferous-like tubules and of Leydig cell clusters. The tubules were filled with clear Sertoli cells, few degenerative dark cells and scanty spermatogonia. Thin collagen bundles surrounded the tubules and the foci of Leydig cells without any crystals of Reinke. The immaturity of all these cellular components could be connected with a mutation at a repressive locus which could be responsible for the abnormalities observed in the different steps of androgen action at target cell level.

The XY gonadal agenesis syndrome

A patient with a 46,XY chromosome constitution showed the following main characteristics: eunuchoidal body habitus, lack of secondary sexual development, normal female external genitalia with absence of vagina, no gonadal structures, and complete lack of internal genitalia except for rudimentary ductal structures defined by histological examination. Her condition is clearly different from that of feminizing testis syndrome and Swyer syndrome individuals. We would like to include her and six similar patients from the literature in a newly defined `XY gonadal agenesis' syndrome.