Nuclear androgen binding sites in the male rat. III. Late spermatids and spermatozoa in the testis, with an introduction to epididymal spermatozoa

Semen Characteristics After Overnight Shipping: Preservation of Sperm Concentrations, HspA2 Ratios, CK Activity, Cytoplasmic Retention, Chromatin Maturity, DNA Integrity, and Sperm Shape

We tested several approaches that can be used to preserve sperm attributes and the objective biochemical markers of sperm maturity and function for assessment in a remote centralized laboratory after overnight shipping of semen samples. Addition of phenyl-methyl-sulfonyl-fluoride (PMSF) to a final concentration of 20 microg/mL semen at 4 degrees C has preserved sperm concentrations and HspA2 isoform ratios, even at room temperature, simulating a shipping delay in moderate ambient temperatures. Regarding the attributes of individual spermatozoa, the patterns of CK-immunocytochemistry (demonstrates cytoplasmic retention in diminished-maturity spermatozoa); aniline blue staining pattern (tests chromatin maturity); sperm shape assessed by both Kruger strict morphology and computer assisted morphometry; and sperm DNA integrity, as tested by DNA nick translation, all remained unchanged. Thus, the PMSF-4 degrees C conditions preserved sperm concentrations and the cytoplasmic and nuclear biomarkers of sperm cellular maturity and function for next-day analysis. This shipping method will facilitate the early detection of subtle changes in semen quality that can affect sperm function, even when there has been no decline in sperm concentrations to signal possible toxic effects. Furthermore, sample preservation will enable investigators to evaluate semen for toxicology studies and for diagnosis of male infertility from remote locations. Home collection of semen should enhance study participation, and semen assessment in centralized laboratories will address concerns regarding interlaboratory variations and quality control.

The equivocal presence of nuclear androgen binding proteins in mammalian spermatids and spermatozoa

The presence of nuclear androgen binding proteins measured by nuclear androgen exchange in rat spermatids and spermatozoa was re-examined. Specific binding was observed to be related to less dense contaminating particles when sonicated testes were fractionated by isopcynic centrifugation through a 40-61% Nycodenz linear gradient. No specific binding was observed in a pure preparation of epididymal spermatozoa collected by retrograde perfusion of the cauda epididymidis, even when a nuclear exchange assay of superior sensitivity was used. Contamination could easily be induced by adding prostatic tissue to epididymal spermatozoa prior to sonication. Despite this strong evidence that the measure of nuclear androgen receptors by nuclear exchange in germ cells is artefactual, the persistence of high endogenous concentrations of 5 alpha-dihydrotestosterone and 5 alpha-diols (but not testosterone) in spermatozoa of castrated rats argues for the opposite conclusion.

Testosterone immunoreactivity in rainbow trout (Salmo gairdneri Richardson) testis

Testosterone antiserum raised in rabbits according to conventional techniques was used to localize immunoreactive material in fixed, paraffin-embedded rainbow trout testis. Spermatogonia showed a nuclear label throughout the reproductive cycle; their nucleoli were not stained or stained less intensely. Spermatocytes displayed a staining of large cellular areas, showed an irregularly delineated intracellular label, or remained unstained; similarly stained spermatocytes were arranged in groups. Spermatids remained unstained. Spermatozoa were not labeled or were weakly labeled, which varied from male to male and also between different areas of a section. Sertoli cells showed a label confined to the nucleus. During active spermatogenesis they also carried a cytoplasmic stain. Interstitial cells with a cytoplasmic stain were found only rarely. The spermatocyte I/II transition is associated with the most considerable changes in the intracellular staining pattern.

Nuclear androgen binding sites in the male rat. II. Seminiferous tubules

A nuclear exchange for androgens in the seminiferous tubules of the mature male rat has been established. The exchange, utilizing technology established on the ventral prostate gland described in the previous paper [7], is based upon LH-20 chromatography of salt extract of purified nuclei. The extract is incubated with [3H]methyltrienolone (R 1881) or [3H]dihydrotestosterone (DHT) at 4 degrees C for 21 h. Bound is separated from free on a hydroxylapatite microcolumn. Nonspecific binding is determined by use of 100-fold molar excess of the unlabeled ligand. Specific binding in an incubation volume of 2 ml containing 1.4 nM [3H]R 1881 was 5.78 +/- 0.57 fmol/mg DNA (mean +/- SE). Specific binding was linearly related to protein concentration. Of the steroids studied, only testosterone competed with DHT in suppression of [3H]DHT (one-sixth the affinity). In 4 experiments by saturation analysis, specific binding was saturable and of high affinity: Kd = 6.1 +/- 0.93 X 10(-10), n = 2.2 +/- 0.41 pM (3.75 +/- 0.77 fmol/mg DNA). A second receptor of low affinity and high capacity was also observed: Kd = 3.28 X 10(-7); n = 161 pM (2.46 pmol/mg DNA). In an analysis of specific binding by ultracentrifugation on an 8-34% glycerol density gradient, 2 radioactively labeled peaks were observed, one at 5.6 S, completely suppressed by 100-fold molar excess of unlabeled steroid, and a second larger peak at 3 S, only partially suppressed. The possibility that marginal binding was due to proteolysis could not be confirmed: (1) Addition of nuclear extract from seminiferous tubules to nuclear extract from the ventral prostate enhanced specific binding in the latter; (2) A 4-h delay in processing of seminiferous tubules did not decrease specific binding; (3) A protease inhibitor (PMSF) did not enhance binding. However, sonication of the testes, retaining only late spermatids and spermatozoa, triple specific binding (16.2 +/- 0.8 fmol/mg DNA). These results confirm our previous reports in which we observed by radioimmunologic analysis the presence of androgen receptors in seminiferous tubules, and in late spermatids and spermatozoa. It is suggested that the sonicated testis is an ideal model in which to study the role of the androgen receptor in the maintenance of spermatogenesis.

Nuclear androgen binding sites in the male rat. I. Unoccupied sites in the prostate

A study was made of unoccupied androgen binding sites in the nuclei of ventral prostate glands of male rats. They were measured at 0 degrees C by comparing specific binding of 1 nM [3H]DHT to salt extract of purified nuclei during the first hour with specific binding during both hours. This method was dependent upon demonstrated completion of uptake into unoccupied binding sites within the first hour and linearity of exchange with occupied binding sites during both hours. Unoccupied binding sites were not artefactual. They did not increase if tissue concentration was diluted prior to homogenization, while they decreased if homogenization was delayed after the tissue was minced. They could be occupied, both in vitro (if precharged with at least 1 nM unlabeled DHT) or in vivo, by administering testosterone propionate subcutaneously or by infusing testosterone into the jugular vein. Exposure to a high concentration of unoccupied prostatic cytosolic binding sites (608.4 fmol from castrated rats) as compared to low concentration (29.3 fmol from intact rats) during homogenization had little effect upon nuclear unoccupied binding site concentrations (2.16 fmol/mg DNA vs 2.41 fmol/mg DNA, respectively). In individual rats, concentration of unoccupied nuclear androgen binding sites was 4.61 +/- 1.05 fmol/mg DNA, while total binding site concentration (measured with 10 nM [3H]DHT for 24h at 12 degrees C) was 866 +/- 103 fmol/mg DNA. Unoccupied nuclear binding sites reached their highest concentration in animals 4 months old (15.09 fmol/mg DNA) when animals 21 days through 720 days of age were studied. By use of association and dissociation rates of binding, it was determined that the apparent Kd of nuclear binding sites was 1.11 X 10(-12) M. There were no observed differences between unoccupied and occupied binding sites in steroid specificity or in sedimentation rate in an 8-24% glycerol density gradient. Although no physiological importance can be attributed as yet to unoccupied nuclear androgen binding sites in the prostate, they do provide a convenient comparison with putative androgen binding sites in the nuclei of testicular and epididymal germ cells.