Biomedical subjects

R P Amann

Publications and source records attributed to R P Amann.

At least 19 recordsLinked to original sources

PubMed2001

Long-term effects on male reproduction of early exposure to common chemical contaminants in drinking water.

We evaluated sequelae to early exposure of male rabbits to drinking water containing chemicals typical of ground water near hazardous waste sites. The mixture (p.p.m. at 1x) was 7.75 arsenic, 1.75 chromium, 9.25 lead, 12.5 benzene, 3.75 chloroform, 8.5 phenol and 9.5 trichloroethylene. Dutch-Belted does received mixture at 0x (deionized water; control), 1x or 3x as drinking water from day 20 pregnancy through weaning. Exposure of individual males (7-9/treatment) continued until 15 weeks (adolescence); then, all males received deionized water. At 57-61 weeks of age, ejaculatory capability and seminal, testicular, epididymal and endocrine characteristics were evaluated. At 10 opportunities with a female teaser, all seven control males ejaculated every time, but 12 of the 17 treated males failed to express interest, achieve erection and/or ejaculate on one to five occasions; four of the 12 accomplished ejaculation with a second male teaser. Total spermatozoa/ejaculate and daily sperm production were unaffected. However, treatment caused (P < 0.03) acrosomal dysgenesis and nuclear malformations. Baseline serum concentrations of LH were lower, but with borderline significance (P = 0.05). Testosterone secretion after exogenous human chorionic gonadotrophin (P < 0.04) was low. Thus, even at 45 weeks after last exposure to drinking water pollutants, mating desire/ability, sperm quality, and Leydig cell function were subnormal.

Animals↗

PubMed2000

Fertilizing potential in vitro of semen from young beef bulls containing a high or low percentage of sperm with a proximal droplet.

Fertilizing potential of semen containing a high percentage of sperm with a proximal droplet was evaluated using IVF. Design criteria: (a) specified semen with >100 x 10(6) sperm/mL with >40% progressively motile spermatozoa, after collection via electro-stimulation; (b) designated a droplet group, bulls whose semen contained >30% spermatozoa with a proximal droplet and <25% with other morphological abnormalities, and a control group, with <25% abnormalities of any type; and (c) stipulated evaluations at 11 to 13 mo of age and again -4 wk later. At the initial evaluation, when a bull was assigned to the droplet group, the next bull meeting control criteria was designated his pair; 15 pairs in four herds were studied. Semen was extended in egg-yolk citrate, cooled to 5 degrees C over approximately 2.5 h, and held at 5 degrees C. After 20 to 44 h, spermatozoa were processed by swimup, incubated with heparin, and co-cultured with oocytes (35 to 56 oocytes/sample; 18 h). Ova were observed for cleavage approximately 42 h after co-culture, and further development was evaluated on day 8. At first evaluation, cleavage rates were 18 and 46% for droplet and control groups (P < 0.01); semen had 34 to 70% and 0 to 12% droplet spermatozoa. For 10 of 15 droplet bulls, <10% of ova were cleaved whereas cleavage rate was >15% for all control bulls. At second evaluation, only three droplet bulls still had >30% of spermatozoa with a proximal droplet. Cleavage rates increased accordingly; only four droplet bulls had <10% cleaved ova and 10 had >34% cleaved ova. Three control bulls had <10% cleaved ova and nine had > or = 34% cleaved ova. Considering all 60 ejaculates, correlation between percentage of spermatozoa with a proximal droplet and percentage of cleaved ova was -0.49 (P < 0.0 1). Correlations between percentages of motile or normal spermatozoa in field evaluations and outcome in IVF were 0.28 and 0.52. Laboratory evaluations of spermatozoa concomitant with preparation for IVF revealed that only incidence of proximal droplets appeared related to outcome in IVF. We concluded: (a) semen from most yearling beef bulls with a high incidence of proximal droplet spermatozoa had severely compromised IVF fertility; (b) as these bulls matured, the incidence of proximal droplets decreased, and IVF fertilizing potential increased; and (c) semen containing >30% spermatozoa with a proximal droplet is strong evidence that fertilizing potential of the bull will be low until the incidence decreases.

Acrosome↗

PubMed2000

Exposure of turkey sperm to a synthetic peptide before insemination increases fertility.

Effects on fertility and hatch of eggs laid by hens inseminated with sperm exposed to a synthetic peptide were studied. Pooled semen from 40 randomly selected toms was split and held in vitro for 0 or 24 h before use. Just before insemination, sperm (at 8.33x10(9) sperm/mL) were exposed for 5 min to 0.0, 0.05, 0.25, or 0.50 microM peptide. Hens (28 per group) were inseminated within less than 30 min with 250x10(6) in 30 microL. Two inseminations 24 h before onset of lay were followed by weekly inseminations through 22 or 20 wk. For sperm that was fresh or held 24 h, peptide treatment (P<0.02 or 0.01) and week of lay (P<0.01) affected fertility and hatch of total eggs set. There was no effect of peptide treatment on hatchability of fertile eggs. For fresh sperm, use of 0.25 microM peptide, but not 0.05 or 5.0 microM peptide, increased (P<0.05) fertility and hatch of total eggs set compared with the control (0 microM). Values for fertility were 94 vs. 90% and for hatch were 84 vs. 80%. Increases in hatch were especially evident for fresh sperm after approximately 13 wk of lay.

Animal Husbandry↗

PubMed1999

Issues affecting commercialization of sexed sperm.

A decision tree for genetics or sperm-sexing entities considering sales of sexed sperm is discussed in terms of: (a) how best to avoid harm; (b) how best to do good; (c) needed synergy with other assisted reproductive technologies; (d) constraints on biotechnology; and (e) costs with current and likely technologies versus potential benefits to producers. The sexed-sperm industry might wish to take a pro-active stance on societal issues potentially affecting use of sexed sperm. For most sales in animal agriculture, cost of added value must be < 50% of benefit. Cost is less important for emotionally-driven uses with horses and human beings. Current procedures for flow-sorting allow most sperm to retain their fertilizing potential. Added cost to produce and package 2 x 10(6) sperm is estimated at US $30 to US $46 with flow sorted sperm. Estimating cost of any alternative technology is premature. For IVF/embryo transfer (ET), cost and numbers of flow-sorted sexed sperm are appropriate for commercial use. For use in low-dose AI, however, added cost to supply one insemination dose must be near US $12. Flow-sorting instruments with higher throughput and lower purchase and operating costs are obligatory for economic application in most AI situations. Developers of antibody-based separations also will face issues of retention of fertilizing potential while minimizing cell loss, separation of living from dead sperm concurrent with sperm sexing, output, and cost. To benefit producers and consumers in a changing world, genetics and sperm-sexing companies will have to collaborate and interface to provide funding for needed research and development and to recover these costs, using mechanisms not yet obvious.

Animals↗

PubMed1999

Lessons for the poultry industry gleaned from experiences with other commodity species.

Do breeders really know how well or poorly they are managing reproduction? Poultry breeders could benefit from application of proven concepts of reproductive management used to exploit elite mammalian males, via selection for reproductive traits and extensive use of AI. Use of elite males could dramatically increase the impact of genes of economic importance transferred to the producer level. Testes weight has up to a 35-fold range among males within most lines of poultry, as does number of sperm that can be harvested from a male. These observations should not be ignored. Males with small testes will provide few sperm and they should be culled. Similarly, identification and elimination of males whose sperm are likely to have low fertilizing potential should be beneficial. Approaches to maximize harvest of those sperm produced by an elite male and minimize wastage of these valuable cells are emphasized. To this end, semen should be extended to allow insemination of a minimal volume containing just sufficient sperm consistent with the breeder's goal. Presumably, the goal should be obtaining the maximum number of offspring from a unique male or great-grandparent family, while minimizing cost of producing each chick. This goal might not require maximizing "fertility". A 10-fold increase in dissemination of DNA from elite males to the next generation is realistic. Over three generations, this increase equals a 1,000-fold increase in the number of birds with the desirable traits! Appropriate biotechnology is available. Will decision makers evaluate new (to them) approaches and progress into the next millennium using modern technology, when cost-effective, or will they continue to manage reproduction with methods more than 50 yr old? Those who choose the latter path may risk extinction.

Animal Husbandry↗

PubMed1999

Identifying potentially subfertile toms via a sperm-binding assay.

We evaluated the utility of the commercial version of a new sperm-egg binding assay for detection of differences in sperm quality in samples of turkey semen from individual toms. Each sample had a swirl of 2 or more on a scale of 0 to 4. For assays conducted with fresh semen at 4 x 10(6) sperm per well, values ranged from 0.11 to 12% sperm bound to an extract of perivitelline membrane. Within-male variation averaged 0.17 percentage units, based on three ejaculates per male evaluated. Two experiments compared fertility and hatch for hens after weekly insemination with pooled semen from subpopulations of toms classified as having sperm with LOW or HIGH binding. Average fertility and hatch were lower (P < 0.05) for eggs laid by hens inseminated with semen from LOW toms in one experiment. In another experiment, hen fertility was not different between treatments after insemination during Weeks 32 to 39; however, a sharp decline in hatch was observed only for hens inseminated with semen from LOW toms after 40 wk of age. With semen from HIGH toms, hatch remained at > or = 80%. For these experiments, approximately 7% more poults were obtained from hens inseminated with semen from HIGH toms. We demonstrated that the sperm-egg binding assay detects differences in sperm quality between individuals, and these differences influence fertility.

Animals↗

PubMed1998

Hypergravity does not affect testicular function.

BACKGROUND: A previous study revealed that exposure of rats to microgravity for 14 d on Cosmos 2044 reduced production of testosterone by > 80%, although spermatogenesis remained essentially normal. METHODS: To ascertain if testicular function was altered in hypergravity, 60-d-old rats were randomly assigned to 2 groups (10 per group) and subjected to 14 d of centrifugation to expose them to a total of 2G, or held at unit gravity in similar cages without centrifugation (control). RESULTS: After 14 d, body weight of 2G rats was essentially unchanged, whereas that of control rats had increased; 310 vs. 377 g (p < 0.05). Testes weight, production and secretion of testosterone, diameters of seminiferous tubules and their lumina, data from subjective evaluation of spermatogenesis, and counts of homogenization-resistant spermatids all were similar for 2G and control rats. CONCLUSION: It was concluded that exposure of male rats to 2G for 14 d had no major effect on testicular function whereas, based on earlier studies, exposure to microgravity (< 10(-3) x gravity) for 11-14 d suppressed production of testosterone by Leydig cells and reduced concentrations of anabolic steroids available to peripheral tissues.

Animals↗

PubMed1993

The epididymis and sperm maturation: a perspective.

In common mammals, sperm leaving the testis are incapable of fertilizing a female gamete. Sperm have limited biosynthetic capability and need to minimize demand for ATP. Hence, modification of sperm to achieve their maturation requires pre-programmed cleavage of integral molecules (planned self-modification) and remodelling by action of molecules found in the suspending fluids. Most of these biocatalysts are secreted by a series of specialized regions in the epididymal epithelium, but some are provided in seminal plasma. The role of the epididymis in sperm maturation is postulated to be 'setting a series of triggers' each capable of initiating cellular changes either at emission or near or in the oocyte, and 'setting a safety' for each trigger to prevent premature occurrence of the event. The attributes required in a spermatozoon for in vitro fertilization and natural mating are different, and their expression is dependent on the site of sperm sampling. Some attributes needed for fertility are probably like an on-off switch, whereas others probably allow a gradually reduced probability of success before going to the off position (analogous to a conventional light switch and a dimmer-type light switch). All essential attributes of a spermatozoon must be expressed in a 'combined effective amount' for that cell to be fertile. Because of mixing, in any segment of the epididymal duct the population of sperm is heterogeneous in age and biological status. Thus, when assessing sperm maturation it is necessary to establish the proportion of sperm that has completed and retained all steps of maturation necessary to achieve fertilization of oocytes under the conditions imposed. In a normal animal, most sperm leaving the epididymis have a 'combined effective amount' of attributes, and the population has a high fertilizing potential.

Animals↗

PubMed1992

Effects of microgravity or simulated launch on testicular function in rats.

Testes from flight rats on COSMOS 2044 and simulated-launch, vivarium, or caudal-elevation control rats (5/group) were analyzed by subjective and quantitative methods. On the basis of observations of fixed tissue, it was evident that some rats had testicular abnormalities unassociated with treatment and probably existing when they were assigned randomly to the four treatment groups. Considering rats without preexisting abnormalities, diameter of seminiferous tubules and numbers of germ cells per tubule cross section were lower (P less than 0.05) in flight than in simulated-launch or vivarium rats. However, ratios of germ cells to each other or to Sertoli cells and number of homogenization-resistant spermatids did not differ from values for simulated-launch or vivarium controls. Expression of testis-specific gene products was not greatly altered by flight. Furthermore, there was no evidence for production of stress-inducible transcripts of the hsp70 or hsp90 genes. Concentration of receptors for rat luteinizing hormone in testicular tissue and surface density of smooth endoplasmic reticulum in Leydig cells were similar in flight and simulated-launch rats. However, concentrations of testosterone in testicular tissue or peripheral blood plasma were reduced (P less than 0.05) in flight rats to less than 20% of values for simulated-launch or vivarium controls. Thus spermatogenesis was essentially normal in flight rats, but production of testosterone was severely depressed. Exposure to microgravity for greater than 2 wk might result in additional changes. Sequelae of reduced androgen production associated with microgravity on turnover of muscle and bone should be considered.

Animals↗

PubMed1992

Ultrasonographic and quantitative histologic assessment of sequelae to testicular biopsy in stallions.

A sample of testicular parenchymal tissue, approximately 2 x 7 x 7 mm, was aseptically removed from 1 testis in each of 9 stallions on day 0. Slight to moderate hemorrhage from the tunica albuginea was observed in 8 stallions, but bleeding from the parenchyma was detected in only 2 stallions. Stallions were castrated 27 days later. Normal development of granulation tissue was evident at the biopsy site, but hematomas were not observed. In situ measurement of the widths of the right and left testes, total scrotal width, and evaluation of testicular echogenicity during ultrasonography were variables used to monitor changes in the testicular parenchyma from 14 days before biopsy through 27 days after biopsy. The control testis was consistently larger than the biopsied testis, except for day 3. Ultrasonography revealed signs of a localized change in the parenchyma of the biopsied testis in 4 stallions, but each lesion decreased in size by day 27. Tissues removed during biopsy enabled an excellent appraisal of spermatogenesis at that time. Detailed examinations of seminiferous tubules in the testes were performed to assess for damage to testicular function. At castration, samples were taken from 6 sites in each testis. Quantitative histologic evaluations of testicular tissues revealed low numbers of spherical spermatids and pachytene spermatocytes in biopsied testes, compared with control testes. It was concluded that there was a transitory increase in degeneration of preleptotene spermatocytes and B spermatogonia at the time of biopsy. A mild inflammatory response at the biopsy site in some testes was evidenced by an increased number of leukocytes at the biopsy site and at a dorsal site.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Effect of pulsatile or continuous administration of GnRH on reproductive function of stallions.

Gonadotrophin-releasing hormone (GnRH) was administered subcutaneously to reproductively normal stallions, either in a pulsatile manner (10 micrograms GnRH/2 h; n = 6) or as a continuous infusion (10 micrograms GnRH/2 h; n = 6), and in a pulsatile manner to 9 reproductively abnormal stallions, from February to July, 1988. Hormonal secretion patterns, testicular parameters and semen characteristics were monitored before and during treatment. In general, pulsatile GnRH caused a significant increase (P less than 0.05) in luteinizing hormone (LH) concentrations in the peripheral blood of normal stallions. LH levels also appeared to increase in abnormal stallions but the rise was not significant (P greater than 0.05). Stallions given GnRH by continuous infusion and the untreated control stallions did not show an increase in LH concentrations during the treatment period. None of the treatments resulted in significant increases in peripheral blood concentrations of testosterone, although individual stallions that showed an increase in LH secretion appeared to show some increase in testosterone secretion rate. In general, and for individual stallions, none of the treatments resulted in increased total scrotal width, total number of spermatozoa per ejaculate or the percentage of progressively motile spermatozoa in the ejaculate. It was concluded that although pulsatile administration of GnRH may increase the secretion rate of LH and, consequently, testosterone, this adjustment does not increase testicular size or output and motility of spermatozoa.

Animals↗

PubMed1990

Morphological features of principal cells in the ovine epididymis: a quantitative and qualitative study.

Functions of the epididymis differ by region, and this may be reflected in epithelial structure. Therefore, tissues from the initial segment (IS), proximal and central caput (PCap, CCap), and proximal and central corpus (PCor, CCor) epididymidis were examined by light and transmission electron microscopy. The proportion of principal cells in the epithelium was highest (p less than 0.05) in the CCap (74%) and lowest in the CCor (68%), whereas proportions of basal cells (25%), apical cells (1.4%), and white blood cells (2%) were similar in all regions. Volume density (VD) of the nucleus was lower (p less than 0.05) in principal cells in the IS (7%) than in other regions (10%). There was no regional difference in VD of the Golgi complex (14%) or endoplasmic reticulum (19%) in principal cells. The VD of mitochondria averaged 4% in the IS through CCap, but only 2.5% in PCor or CCor (p less than 0.05). The VD of clear vesicles + multivesicular bodies (8%) and dense vesicles (6%) were higher (p less than 0.05) in the CCap than in other regions (1% each), while there were more lipid droplets (12%) in the PCor than in other regions (less than or equal to 2%). Most quantitative differences in VD of organelles within principal cells were small even though significant. However, there were profound differences in the morphological features of the Golgi complex, endoplasmic reticulum, and mitochondria among regions.

Animals↗

PubMed1990

Oxytocin in the ovine ductuli efferentes and caput epididymidis: immunolocalization and endocytosis from the luminal fluid.

The presence, possible biosynthesis, and uptake of oxytocin from luminal fluid in the ductuli efferentes and caput epididymidis of the ram were studied. Specific immunostaining for oxytocin, but not neurophysin, was observed in the ductuli efferentes as well as caput epididymidis. This indicates the presence, but not production, of oxytocin in epithelial cells of these ducts. Staining was predominantly present in the epithelium, especially in the middle lobules of the ductuli efferentes and initial segment of the epididymis. Endocytosis of oxytocin was studied by electron microscopy after intraluminal microinjections of oxytocin conjugated to colloidal gold (8-10 nm), a 20-fold excess of oxytocin followed by oxytocin-gold, or plain colloidal gold into the ductuli efferentes and four successive regions of the caput epididymidis. Specific uptake by a receptor-mediated process was evidenced by the presence of more gold particles within epithelial cells after oxytocin-gold injections than after control injections. The quantity of oxytocin-gold endocytosed was 3.7-fold greater in the ductuli efferentes than in the initial segment of the epididymis. Within the caput epididymidis, more oxytocin-gold was endocytosed in the initial segment and proximal caput epididymidis than in two distal regions. We conclude that localization of oxytocin in epithelia of the excurrent ducts is a consequence of endocytosis (predominantly receptor mediated) of luminal oxytocin entering in rete testis fluid; however, uptake of blood-borne oxytocin cannot be excluded. Although oxytocin may have a role in sperm transport via action on smooth muscle in the ductal wall, the regional pattern of endocytosis of oxytocin is suggestive of a role for oxytocin in epithelial function in the ductuli efferentes and proximal portions of the caput epididymidis.

Animals↗

PubMed1990

Testicular growth, hormone concentrations, seminal characteristics and sexual behaviour in stallions.

Puberty was studied using 15 colts of Quarter Horse phenotype. Total scrotal width was measured every 8 weeks from 48 to 96 weeks. Blood samples were taken from 8 colts at 8, 16 and 24 weeks and then every 4 weeks until 100 weeks to measure changes in LH, FSH and testosterone concentrations. Seminal collections were attempted monthly from 48 to 64 weeks and every 2 weeks thereafter until puberty resumed every 3rd day from 96 weeks for 15 ejaculates. For all collections, times to erection, mount and ejaculation and seminal characteristics were recorded. Age at puberty was defined as the first ejaculate containing 50 x 10(6) spermatozoa, with greater than or equal to 10% motile. Colts were castrated at 2 years to enable determination of daily sperm production (DSP), epididymal sperm reserves and normality of spermatogenesis. Total scrotal width increased linearly from 48 to 96 weeks. Age at puberty averaged 83 weeks (56-97 weeks). Changes in serum concentrations of LH and FSH were parallel, rising at 36-40 weeks, declining after 40 weeks and rising again at 68-80 weeks. Testosterone was low until 68 weeks after which concentrations rose slowly to 80 weeks and increased rapidly to a plateau at 92 weeks. Sexual behaviour and seminal characteristics differed (P less than 0.05) between puberty and 2 years, except for time to erection, time to mount, and percentage of motile spermatozoa. DSP at 2 years averaged 1.7 x 10(9) and daily sperm output (DSO) averaged 1.1 x 10(9). The correlation between DSP and DSO was 0.83 (P less than 0.01). There were 9.57 x 10(9) spermatozoa/epididymis of which 67% were in the cauda.

Animals↗

PubMed1990

Effect of maternal treatment with altrenogest on pituitary response to exogenous GnRH in pubertal stallions.

The pituitary response to exogenous GnRH was studied in 8 colts of Quarter Horse phenotype from 32 to 96 weeks of age. Colts were from dams treated daily from Day 20 to 325 of gestation with (1) 2 ml neobee oil per 50 kg body weight (controls); or (2) 2 ml altrenogest per 50 kg body weight. GnRH challenges (5 micrograms/kg body weight) were administered every 8 weeks from 32 to 96 weeks of age to estimate pituitary content of LH. Blood samples were collected every 20 min for 4 h before GnRH and 15, 30, 45, 60, 90, 120, 180, 240 and 360 min after GnRH. Serum concentrations of LH and FSH were determined for the 2 pre-GnRH and all post-GnRH samples. Baseline concentrations (mean of 2 pre-GnRH samples) of LH and FSH were not affected by treatment (P greater than 0.05). Serum concentrations of LH declined from 40 to 56 weeks and rose again between 72 and 80 weeks. Basal concentrations of FSH declined from 32 to 56 weeks, and varied widely after 56 weeks. The maximum LH response to GnRH (highest concentration after GnRH minus baseline) declined steadily in both groups for 48 to 64 weeks but remained relatively constant in both groups after 64 weeks. The maximum FSH response to GnRH declined from 32 to 64 weeks then remained relatively constant in both groups. The GnRH-induced gonadotrophin release remained low with a transient increase at 72 weeks for both hormones.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Optimal replication for histometric analyses of testicular function in rats or rabbits.

Quantitative evaluations of testicular histology can provide sensitive endpoints for determining toxicity of chemicals to the male reproductive system. But, the numbers of observations per testis or number of animals per treatment group often are selected by tradition or availability, rather than from a statistical basis. Therefore, we studied the number of observations per male (sampling intensity) and number of animals per treatment (replication) needed to detect treatment effects of given magnitude, with predictable error probabilities, using data from Sprague-Dawley rats and Dutch-belted rabbits that received 0.0, 0.94, 1.88, 3.75, 7.5, or 15.0 mg/kg body wt of 1,2-dibromo-3-chloropropane (DBCP). Data for one testis from 102 rats and 34 rabbits were available. For each testis, observations included measurement of the minor diameter of 50 seminiferous tubules, counts of the number of leptotene primary spermatocytes per 250 Sertoli cells, and counts of spherical spermatids within 20 seminiferous tubular cross sections. Tabular data are presented showing optimal numbers of observations per testis and animals per treatment group as a function of the difference to be detected and selected probabilities for Type I and II errors. In general, precise assessments required far fewer observations per testis than are used routinely. However, due to the inherent variability among animals, the number of animals required per treatment tended to be greater for experiments with the rabbit, and increased substantially for both species when detection of small differences had to be ensured. The data presented should enable investigators to design experiments of chosen sensitivity and precision while making cost-effective use of animals and labor.

Animals↗

PubMed1989

Immunolocalization and concentrations of inhibin alpha in the ovine testis and excurrent duct system.

Inhibin was localized in the ovine testis, excurrent ducts, and accessory sex glands by using a rabbit antiserum against a synthetic polypeptide representing the first 30 amino acids of porcine inhibin alpha-subunit. Concentrations of inhibin in fluids entering and leaving the epididymis also were determined in a radioimmunoassay using the same antibody. In the testis, immunostaining of inhibin was conspicuous in the seminiferous epithelium. Leydig cells occasionally were stained and the tunica media of blood vessels always was stained. Intense staining was observed in the epithelia lining the rete testis and ductuli efferentes. Staining also was intense in the epithelium of the initial segment and proximal caput epididymidis, and became less intense along the length of the epididymis. These observations were consistent with concentrations of inhibin in rete testis fluid (8.2 pmol/ml) entering the ductuli efferentes and in cauda epididymal plasma (0.67 pmol/ml) leaving the epididymis. Epithelia of ampullary and vesicular glands and of some prostatic acini were positively stained, but bulbourethral glands were never stained. Adrenal cortex, some proximal convoluted tubules in the kidney, and transitional epithelium of the urethra also were stained. Based on radioimmunoassay data and fluid flow rates for the ram, it was concluded that almost all of the 328 pmol inhibin that enters the ductuli efferentes daily is endocytosed in the proximal parts of the excurrent duct system. The physiological role(s) for inhibin, or inhibin-like peptides, in the excurrent duct system remains speculative.

Adrenal Glands↗

PubMed1989

Localization of androgen receptors in ram epididymal principal cells.

Androgen receptor was immunolocalized in the epididymal epithelium of rams and in isolated cells using an antibody against a synthetic polypeptide representing a portion of the androgen receptor. Immunostaining was predominant in the epithelium in tissue sections. Concentrations of androgen receptor were determined in cells from the central caput, distal caput, and central corpus epididymidis enzymically dissociated and elutriated to provide two fractions. On the average (n = 18), Fraction I contained 8% principal cells while Fraction II contained 71% principal cells; the stromal cells in each fraction were primarily smooth muscle and fibroblasts. For each sample, the number of DHT receptors (fmol) per 10(6) total cells was greater in Fraction II than in Fraction I. Few cells in Fraction I were immunostained for androgen receptor, whereas most cells in Fraction II were intensely stained. The numbers of DHT receptors per cell, or per principal cell, were similar for the central caput and distal caput, but lower in the central corpus epididymidis. The results support our hypothesis that most epididymal DHT receptors are localized in principal cells and confirm that the region between the central caput and proximal corpus of the ram epididymis is most dependent on androgen stimulation.

Animals↗