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Background We have recently suggested that homozygosity for a specific 'AGATA' haplotype within a approximately 50 kb linkage disequilibrium (LD) block of the gene for estrogen receptor alpha (ESR1) may raise the susceptibility to cryptorchidism by enhancing estrogenic effects of environmental endocrine disruptors (EEDs). Methods Haplotype analysis of ESR1 was performed in 328 Japanese subjects, i.e. 70 patients with micropenis (MP), 43 patients with hypospadias (HS), 80 patients with spermatogenic failure (SF) and 135 control males. Genotyping was performed by the 5' nuclease assay. Results The LD block was identified in each of the patient groups and in the control males. The frequency of homozygotes for the specific 'AGATA' haplotype was markedly higher in the HS patients [P = 0.0000033, odds ratio [OR] = 11.26] and slightly higher in the MP patients (P = 0.034, OR = 3.64) than in the control males, and the 'AGATA' haplotype was strongly associated with HS (P = 0.0000022, OR = 11.26) and weakly associated with MP (P = 0.040, OR = 3.64) in a recessive mode. There was no significant difference between the SF patients and the control males. Conclusions Our results support the hypothesis that homozygosity for the specific ESR1 'AGATA' haplotype may increase the susceptibility to the development of male genital abnormalities in response to estrogenic EEDs.

Translation of a number of mRNAs is under strict regulation via RNA-binding proteins in the spermatogenic cells of testes. A family of Y-box binding proteins represents promising candidates for these presently uncharacterized RNA-binding proteins. The effects of heat stress on the expression of a Y-box binding protein, YB2/RYB-a, and mouse protamine 2 (mP2) were investigated in cultured spermatogenic cells and mouse testes by immunoblot and Northern blot analyses. Localization and alterations in the expression of the YB2/RYB-a protein and the mP2 mRNA in heat-stressed testes were examined by immunohistochemistry and in situ hybridization, respectively. Levels of the YB2/RYB-a protein in spermatogenic cells decreased rapidly as the result of exposure to higher temperature, 378 Co r 438C, compared with the scrotal temperature, 32.58C, under the culture conditions used. In experimental cryptorchidism, levels of the YB2/RYB-a protein were decreased after Day 10, while the mRNA levels were affected only slightly. The levels of the mP2 mRNA were also decreased and about comparable with those of the YB2/RYB-a protein. Exposure of the lower abdomen to a high temperature, 438C for 15 min, also damaged the testis and led to a decrease in YB2/RYB-a protein and the mP2 mRNA levels in a coordinated manner. Because YB2/RYB-a is proposed to function as a stabilizer of mP2 mRNA, the perturbation of YB2/RYB-a by heat stress could account for the decline of the mP2 mRNA in elongated spermatids. gene regulation, spermatid, spermatogenesis, stress

BACKGROUND Mutations of the androgen receptor (AR) gene give rise to a wide array of phenotypic abnormalities. A systematic analysis of the AR gene in patients with 47,XXY has not previously been performed. METHODS Mutations of the AR gene and expansion of the CAG repeats in exon 1 of the AR gene were studied in 13 patients with Klinefelter's syndrome either with (n = 1) or without (n = 12) spermatogenesis. RESULTS No abnormalities in the AR gene were detected by single strand conformational polymorphism analysis. The CAG lengths ranged from 17 to 27 (mean +/- SD 22.8 +/- 3.3, median 23) for Klinefelter patients or from 17 to 28 (mean +/- SD 23.2 +/- 2.6, median 23) for control subjects. X-inactivation analysis for the methylation status of the AR gene was performed in seven patients who were heterozygous for CAG repeats of different length, showing that the longer CAG repeat alleles underwent random but more frequent inactivation in five patients and skewed inactivation in two. CONCLUSIONS An AR gene abnormality does not constitute an important factor for impaired spermatogenesis in patients with Klinefelter's syndrome.

The influence of immobilization stress on testicular germ cell apoptosis was investigated in rats. A transient increase in serum corticosterone and a transient decrease in serum testosterone were observed during each period of immobilization stress. Twenty-four hours after the last immobilization session, the testicular weight and serum concentrations of corticosterone and testosterone were the same between the immobilization stress and control groups. However, the percentages of apoptotic tubules and apoptotic cells in the stress group were significantly higher than those in controls (P < 0.001). These facts suggest that immobilization stress can enhance testicular germ cell apoptosis in rats.

Fertilization and embryo development following intracytoplasmic injection of round spermatids collected from hybrid sterile mice (BALB/c) were investigated. The rates of oocyte activation, blastocyst formation and development into live offspring were compared with those after intracytoplasmic injection of round spermatids from fertile mice (B6D2F1). The injection of oocytes with round spermatids from hybrid sterile or sterile males resulted in similar rates of normal fertilization and embryo development. The rates of development to term of 2-cell embryos were also similar, regardless of the origin of the round spermatids injected. This finding suggested that round spermatids from hybrid sterile mice have the ability to fertilize normally and to allow normal embryo development.

This study was undertaken to determine whether primary spermatocyte nuclei can complete meiosis after transfer into maturing or mature oocytes and can participate in normal embryogenesis. When injected into maturing mouse oocytes at prometaphase of the first meiotic division, spermatocyte chromosomes became arranged on a first meiotic metaphase (Met-l) spindle. Thus, oocytes contained two sets of Met-I chromosomes. When these oocytes were matured in vitro and artificially activated, pronuclei and polar bodies of both maternal and paternal origin were formed, and zygotes began development. When single spermatocyte nuclei were injected into fully mature oocytes at metaphase of the second meiosis (Met-ll), the spermatocyte nuclei transformed into a Met-I configuration, resulting in the formation of oocytes with both maternal (Met-Il) and paternal (Met-I) chromosome complements. After activation of these oocytes, half of each chromosome set was separated into polar bodies. Transfer of nuclei from polar bodies of "paternal" origin into other Met-II oocytes resulted in the formation of oocytes with two sets of Met-Il chromosomes, one maternal and one paternal in origin. When activated, two pronuclei and two polar bodies were formed and zygotes began development. It is concluded that nuclei of primary spermatocytes are able to undergo two successive meiotic divisions within oocyte cytoplasm. Thus, factors that drive chromosome condensation, organization of metaphase, and chromosome separation at anaphase in oocytes can drive these same maturation processes in primary spermatocyte nuclei. When a total of 258 two-cell embryos were transferred to foster mothers, only two live pups were born to two mothers. One died shortly after birth and the other 3 wk after birth. The reasons for poor embryonic and neonatal development remain to be determined.

We have analysed the CAG repeat length in exon 1 of the androgen receptor gene in 48 Japanese males with cryptorchidism and 100 fertile Japanese males. The CAG repeat length was 23.4 +/- 0.48 (mean +/- SE) (range 16-32, median 23) in cryptorchid patients and 23.5 +/- 0.29 (range 15-32, median 23) in normal males. There was no significant difference between the two groups. The expansion of the CAG repeats in exon 1 of the androgen receptor gene is unlikely to constitute a major cause of cryptorchidism.