Estrogen-induced morphological and immunohistochemical changes in stroma and epithelium of rat ventral prostate.

Prostatic smooth muscle cells have been regarded to play a major pathogenetic role during the development of benign prostatic hyperplasia (BPH) in elderly men. Altered hormonal signals (increased estrogen) have been made responsible for the "metabolic" transformation of prostatic smooth muscle cells, which were thought to produce increased amounts of connective tissue fibers observed in BPH. In order to find out the role of metabolically "activated" smooth muscle cells, hormone stimulation experiments were performed in male rats. The effects of androgen deprivation and estrogen stimulation were recorded by semiquantitative analysis of intermediate and myofilament proteins in stromal smooth muscle cells. In castrated or estrogen-treated or estrogen-treated and castrated animals, the reduction of the glandular lumen is the most obvious morphological alteration, accompanied by an increase in connective tissue. Regressive changes occurred most rapidly in castrated animals (already within the first week), slower in castrated estrogen-treated animals and still slower in normal estrogen-treated animals. Regression of the epithelium was accompanied by a marked decrease in immunoreactivity for prostatic binding protein (PBP) in castrated animals, while PBP immunoreactivity in estrogenized animals was retained for up to 6 weeks. Smooth muscle cells became atrophic in castrated animals. This effect was attenuated in estrogen-treated animals. There was no indication for enhanced collagen synthesis by smooth muscle cells. Actin and desmin-immunoreactivity were only slightly altered in experimental animals and showed a changed distribution pattern. Prostatic smooth muscle cells respond less markedly to hormonal alterations than do the fibroblasts.     

Phenotypic diversity and testosterone-induced normalization of mutant L712F androgen receptor function in a kindred with androgen insensitivity

Molecular causes of phenotypic diversity in androgen insensitivity syndrome, occurring even in the same family, have rarely been identified. We report on a family with four affected individuals, three brothers (B1-3) and their uncle, displaying strikingly different external genitalia: B1, ambiguous; B2, severe micropenis; B3, slight micropenis; and uncle, micropenis and penoscrotal hypospadias. All had been assigned a male gender. We detected the same L712F mutation of the androgen receptor (AR) gene in each subject. Methyltrienolone binding on cultured genital skin fibroblasts of B2 suggested moderate impairment of the ligand-binding domain [maximal binding capacity, 38.2 fmol/mg protein (normal); Kd, 0.21 nmol/L; normal range, 0.03-0.13 nmol/L]. In trans-activation assays, the mutant 712F-AR showed considerable deficiency at low concentrations of testosterone (0.01-0.1 nmol/L) or dihydrotestosterone (0.01 nmol/L). Remarkably, this could be fully neutralized by testosterone concentrations greater than 1.0 nmol/L. Hence, the 712F-AR could switch its function from subnormal to normal within the physiological concentration range of testosterone. This was reflected by an excellent response to testosterone therapy in B1, B2, and the uncle. Taking into account the well documented individual and time-dependent variation in testosterone concentration in early fetal development, our observations clearly illustrate the potential impact of varying ligand concentrations for distinct cases of phenotypic variability in androgen insensitivity syndrome.     

Expression of two functionally different androgen receptors in a patient with androgen insensitivity

Recently, we demonstrated a previously unknown high rate of de novo mutations of the androgen receptor (AR) gene in androgen insensitivity syndrome (AIS) with some resulting in somatic mosaicism of mutant and wild type AR alleles. However, data on the genotype-phenotype relationship in the latter patients are sparse. We present here a 46,XY newborn with ambiguous genitalia carrying a mosaic of an 866 GTG (Val) → ATG (Met) mutation with the wild type AR gene. This mutation has usually been associated with complete AIS. Accordingly, we found markedly impaired transactivation due to the mutant Met⁸⁶⁶ AR. Essential information arose from Scatchard analysis of methyltrienolone binding on cultured genital skin fibroblasts. We demonstrated for the first time the expression of two functionally different ARs (K_d1: 5.58 nM = mutant, K_d2: 0.06 nM = wild type) in one AIS individual. This finding not only represents an important confirmation for the presence of the somatic mosaicism in the patient, it also indicates the most likely molecular mechanism responsible for the unexpectedly strong virilization of the patient: Androgen action through the wild type AR expressed by part of the somatic cells. Conclusions The present case clearly demonstrates the molecular mechanism by which somatic mosaicism of the androgen receptor gene can modulate in vivo androgen action. It underlines the importance of particular notice on somatic mosaicism in all androgen insensitivity syndrome patients carrying de novo mutations of the androgen receptor gene. Received: 24 August 1998 / Accepted in revised form: 5 January 1999     

A novel homozygous disruptive mutation in the SRD5A2-gene in a partially virilized patient with 5alpha-reductase deficiency

Steroid 5alpha-reductase deficiency is a rare autosomal recessive disorder caused by mutations in the SRD5A2-gene, resulting in diminished dihydrotestosterone (DHT) formation and, hence, in a severe virilization deficit of the external genitalia in patients with 46,XY karyotype. The phenotype of affected individuals is variable and has been reported to range from completely female over genital ambiguity to normal male, depending on the type of mutation and its effect on enzyme activity. Here we report an adolescent 46,XY patient with predominantly female appearance, who had been gonadectomized in early infancy. Genital status revealed a urogenital sinus equivalent to Prader stage III. Molecular genetic analysis demonstrated a homozygous point mutation in exon 2 of the SRD5A2-gene, leading to a premature termination in codon position 111 of the 5alpha-reductase 2 enzyme, and not allowing formation of a functional 5alpha-reductase type 2 enzyme. This case demonstrates that even despite a complete loss of function of 5alpha-reductase type 2, marked virilization is possible, most likely the result of a testosterone (T) effect during foetal life.     

Prevailing therapeutic regimes and predictive factors for prandial insulin substitution in 26 687 children and adolescents with Type 1 diabetes in Germany and Austria.

AIMS: To analyse current therapeutic strategies for prandial insulin substitution in a large number of children and adolescents with Type 1 diabetes in Germany and Austria, along with changes in therapeutic habits and outcome. METHODS: We classified the data of 26 687 patients, treated from 1995 to 2005 in 152 paediatric clinics, using a database established for quality control and scientific surveys in paediatric diabetology (DPV). RESULTS: Seventy-three per cent of all patients (mean age 13.6 years., mean duration of diabetes 5.4 years.) were treated with > or = 4 daily injections (intensified conventional treatment; ICT), 14% with continuous subcutaneous insulin infusion (CSII), 13% with 1-3 injections per day (conventional treatment). Frequency of daily injections increased with age, duration of diabetes and insulin dose. The insulin dose at breakfast was higher than for the evening meal or lunch, from diagnosis onwards. Individuals using insulin analogues received up to 11% higher insulin doses per day compared with patients treated with human insulin. The time of day, age, duration of diabetes, female gender, insulin analogues and ICT all had a significant influence on prandial insulin doses. Although the number of patients treated with ICT or CSII increased over the period of observation, mean glycated haemoglobin (HbA(1c)) was approximately 8.0% each year, and decreased by only 0.01%. CONCLUSIONS: Eighty-seven per cent of patients were treated with ICT or CSII. However, while this percentage increased over the observation period, mean HbA(1c) was almost constant. Longer duration of diabetes, increasing age, female gender, insulin analogues and ICT were associated with higher prandial insulin doses.