Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Groups of male Long-Evans rats 30, 50, or 70 d old were injected subcutaneously (sc) with a single dose of 0, 5.5, 11.5, or 24.6 mumol Cd/kg as cadmium chloride. All animals were killed 60 d after treatment. At 2 h prior to sacrifice, the rats were injected sc with 100 IU human chorionic gonadotrophin (hCG) to maximally stimulate serum testosterone concentrations. After sacrifice the testes, epididymides and seminal vesicles were removed and weighed. Cardiac blood was taken, and serum concentrations of testosterone (sT) and follicle-stimulating hormone (sFSH) were determined. Sperm concentration in luminal fluid collected from the vas deferens was determined. Significant (p less than 0.01) dose-dependent effects for all measured reproductive parameters were noted in the 70-d-old animals, while no effects were seen in the 30- or 50-d-old rats in either seminal vesicles weight or hCG-stimulated sT concentration. In the absence of significant (p greater than 0.05) changes in body weight gain, effects were seen in testes and epididymides weight, sperm concentration, and sFSH in the 70-d-old rats at Cd doses that were lower than those necessary to bring about similar changes in the 30- or 50-d-old animals. The sensitive indicators of Cd exposure in all age groups were testicular weight greater than epididymal weight greater than vas deferens sperm concentration greater than sFSH concentration. Seminal vesicle weight and sT concentration were found to be the least sensitive. Regression analyses indicated a significant interaction of age with dose; the 70-d-old rats required 30-61% less Cd/kg to cause a 50% change in a measured parameter than did the 30-d-old animals, while the 50-d-old rats required 15-47% less.
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PMID:Age-related dose response of selected reproductive parameters to acute cadmium chloride exposure in the male Long-Evans rat. 309 56

m-Dinitrobenzene (m-DNB)-induced testicular atrophy has been attributed to a direct effect upon the germinal epithelium. However, such degenerative changes in the germinal epithelium should induce shifts in the testicular hormonal milieu, which would in turn alter the hypothalamic-pituitary gonadal axis in general. This study evaluated the endocrine status of male rats (killed 3 hr, 24 hr, 1 week, and 2 weeks) following a single oral dose of m-DNB (32 mg m-DNB/kg). Serum and pituitary leuteinizing hormone, follicle-stimulating hormone (FSH), and protactin and hypothalamic gonadotropin-releasing hormone (GnRH) concentrations were determined. Testosterone and androgen-binding protein concentrations in serum, interstitial fluid, seminiferous tubule fluid, and caput epididymis were also determined. In vitro basal and hCG-stimulated testosterone release was determined in the decapsulated testis. Results of the present study indicate that pituitary hormone concentrations and hypothalamic GnRH were unaffected after a single oral dose of m-DNB. Serum FSH was elevated at 2 weeks. There was a transient decrease in serum testosterone at 24 hr, which returned to control values at 1 and 2 weeks. Interstitial fluid, seminiferous tubule fluid, and caput epididymal testosterone concentrations were increased at 1 and 2 weeks. Basal testosterone release in vitro was increased at 2 weeks, while hCG-stimulated testosterone release was increased at 1 and 2 weeks. Androgen-binding protein concentrations in serum and interstitial fluid were increased at 1 and 2 weeks. Androgen-binding protein was increased at 24 hr and 1 week in seminiferous tubule fluid, but returned to control concentrations by 2 weeks. However, the total tubular content of androgen-binding protein was dramatically decreased at 2 weeks. Androgen-binding protein in the caput epididymis was unaltered following m-DNB treatment. These data demonstrate that m-DNB exerts a direct effect on the testes and not through alterations in hypothalamic and pituitary control of gonadal function.
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PMID:Changes in testicular and serum hormone concentrations in the male rat following treatment with m-dinitrobenzene. 313 88

Testis growth is stimulated when short photoperiod-regressed Siberian hamsters are exposed to a lengthening photoperiod, an effect presumably mediated by the pineal gland through a decrease in the peak nocturnal duration of secretion of its hormone melatonin (MEL)(D. S. Carter and B. D. Goldman, Endocrinology 113: 1268-1273, 1983). We examined this stimulatory or "progonadal" effect of MEL in short photoperiod-regressed, adult male Siberian hamsters that were pinealectomized (PINX) and given timed daily subcutaneous 1) injections of MEL (1 or 10 micrograms/day) or saline or 2) infusions of MEL that were "long day-like" (4 h, 10 or 100 ng/day), "short day-like" (10 h, 10 ng/day), or control saline infusions (4 h/day). Photoregressed sham PINX hamsters were transferred to long days at this time. After 5 wk of treatment, 1-microgram MEL-injected hamsters and both groups of 4-h MEL-infused hamsters had stimulatory responses that mimicked those of the long-day-exposed, sham PINX group [i.e., increased testes, body, and epididymal white adipose tissue (EPIWAT) weights, total body fat, EPIWAT lipoprotein lipase activity, and serum prolactin and follicle-stimulating hormone levels]. These effects were not observed in 10-micrograms MEL- or saline-injected and 10-h MEL- or saline-infused hamsters. Thus the peak nocturnal duration of serum MEL is the critical parameter of the MEL secretion profile for stimulating a variety of photoperiodic responses when photoregressed hamsters are exposed to lengthening daylengths.
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PMID:Effects of melatonin on long-day responses in short-day housed adult Siberian hamsters. 314 82

The effects of continuous gamma-irradiation of adult rats at two low-dose rates (7 cGy and 12 cGy/day; up to a total dose of 9.1 Gy and 10.69 Gy 60Co gamma-ray, respectively) were investigated. Over a period of 3-131 days of irradiation, groups of experimental and control animals were killed. Body weight, testis, epididymis, prostate and seminal vesicle weights, the number of germ cells and Sertoli cells, tubular ultrastructure, epididymal and testicular levels of biologically active androgen-binding protein (ABP), and the plasma concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone were monitored. Irradiation had no effect on body weight, whereas testicular and epididymal weight began to decrease following 35 and 50 days of irradiation at 7 and 12 cGy, respectively. At 7 cGy the target cells of the gamma-rays were essentially A spermatogonia, whereas at 12 cGy A spermatogonia and preleptotene spermatocytes were primarily affected. This resulted in a progressive and sequential dose-related reduction in the number of pachytene spermatocytes, round spermatids and late spermatids (LS). Under both irradiation procedures the Sertoli cell number remained unchanged whereas partial (7 cGy) or no change (12 cGy) was seen at the Leydig cell level. Whatever the irradiation protocol, from the time LS numbers decreased, vacuolisation of the Sertoli cell cytoplasm progressively occurred, followed by thickening and folding of the peritubular tissue. Moreover, in parallel to the drop in the number of these germ cell types, ABP production fell whereas FSH levels rose. A highly significant positive correlation was found between LS numbers and these Sertoli cell parameters. This study supports our previous concept of a control of certain important aspects of Sertoli cell function by late spermatids in the adult rat.
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PMID:Influence of germ cells upon Sertoli cells during continuous low-dose rate gamma-irradiation of adult rats. 314 27

Long photoperiod-housed, adult Siberian hamsters were pinealectomized and given daily subcutaneous infusions of melatonin (MEL) to determine which characteristic of the MEL secretion profile is critical for short photoperiod-induced physiological responses. Long-duration MEL infusions (10 or 12 h) given for 5 wk elicited short-day-type responses [i.e., decreased body, testes, and epididymal white adipose tissue (EPIWAT) weights, EPIWAT lipoprotein lipase activity, carcass lipid content, and serum follicle-stimulating hormone and prolactin levels]. In contrast, short- or intermediate-duration (5 or 8 h) MEL infusions or saline infusions were without effect. Long-duration MEL infusions elicited short-day-type responses independently of both the time of day when MEL was administered and of the MEL dose if the latter was greater than or equal to 6.25 ng MEL/daily infusion. The continuity of the 10-h MEL infusions was important for triggering short-day-type responses; 10-h MEL infusions interrupted at their midpoint by 2 h of no infusion were ineffective even though dose and total duration were held constant. The body and lipid mass decreases were independent of the gonads, since castrated and gonad-intact hamsters responded similarly to the daily 10-h MEL infusions. Decreased body weight resulting from long-duration MEL infusions were never accompanied by decreased food intake. We conclude that the peak nocturnal duration of MEL is the critical parameter of the MEL secretion profile for triggering short-day-induced responses in adult Siberian hamsters.
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PMID:Peak duration of serum melatonin and short-day responses in adult Siberian hamsters. 318 92

Male Sprague-Dawley rats were exposed for 8 h to continuous-wave microwave radiation (MWR, 1.3 Ghz) at a mean specific absorbed dose rate of 9 mW/g. MWR exposure and sham-irradiation took place in unidirectionally energized cylindrical waveguide sections, within which the animals were essentially unrestrained. The MWR treatment in this setting was determined to yield an elevation of deep rectal temperature to 4.5 degrees C. The animals were taken for analysis at 6.5, 13, 26, and 52 days following treatment, which corresponded to .5, 1, 2, and 4 cycles of the seminiferous epithelium. Net mass of testes, epididymides, and seminal vesicles; daily sperm production (DSP) per testis and per gram of testis; and the number of epididymal sperm were determined. The levels of circulating follicle-stimulating hormone (FSH) and leutinizing hormone (LH) were derived via radioimmunoassay of plasma samples taken at the time of sacrifice. Despite the evident acute thermogenesis of the MWR at 9 mW/g, no substantial decrement in testicular function was found. We conclude that, in the unrestrained rat, whole body irradiation at 9 mW/g, while sufficient to induce evident hyperthermia, is not a sufficient condition for disruption of any of these key measures of testicular function.
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PMID:Acute, whole-body microwave exposure and testicular function of rats. 357 98

Multidisciplinary and multinational task forces representing principal fields of research in fertility control have been set up by the World Health Organization. One task force is studying agents and methods that interfere with the transport and survival of the ovum, including chemical and surgical methods of occluding the oviducts, postcoital contraceptives, and the effect of drugs on the transport and survival of the ovum. The research of the task force on methods for the regulation of implantation includes investigation of medicated IUDs, immunological methods, and orally active agents disrupting implantation. The lines of research pursued by the task force on methods for the regulation of male fertility are on the mechanism of action of drugs shown to be effective in mammals, studies of epididymal function in relation to sperm maturation, storage, survival and transport, clinical trials of selected gestagen-androgen combinations, and studies designed to identify materials capable of inhibiting the secretion of follicle-stimulating hormone. Another task force is investigating methods for regulating sperm migration and survival in the human female, and aims at developing new agents and systems for their local delivery to the vagina and cervix. The objective of the task force on prostaglandins in fertility is to establish the efficacy, safety, and acceptability of prostaglandins and their analogs for the interruption of pregnancy and as contraceptives. Another task force is investigating the attributes of fertility-regulating methods and the sociocultural and psychological factors that determine acceptability. The assessment of the sequelae of induced abortion is the subject of another task force;y Consideration is being given to research projects on agents stimulating gonadal function and on mechanism of action of hormones and antihormones in relation to the regulation of fertility, developing better pharmacological models for screening new products, and the detection of ovulation.
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PMID:WHO task forces undertake collaborative research and development in fertility regulation. 474 97

In the rat, the effects of progestin and androgen administration on serum, testicular and epididymal androgen binding protein (rABP) concentrations were determined and related to the organ weight and morphology. Adult rats were treated with medroxyprogesterone acetate (MPA; 17 alpha-acetoxy-6 alpha-methylprogesterone), testosterone propionate (TP) and mibolerone (MB; 7 alpha, 17 alpha-dimethyl-19-nortestosterone). MPA reduced testicular and epididymal weights and the concentrations of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone. During MPA treatment testicular and epididymal ABP content declined in parallel with organ weights and hormone concentrations, whereas serum ABP concentrations increased. Combinations of MPA and TP reduced testicular and epididymal ABP, but the reductions were less than with MPA alone; this combined treatment also elevated serum AMP. Both MB and TP reduced ABP in the male reproductive tract, but unlike MPA did not increase the concentration of this protein in serum. The results suggest that MPA acts directly on Sertoli cells resulting in increased ABP release into the blood. The comparison was made of steady state polyacrylamide gel electrophoresis (SS-PAGE) and radioimmunoassay (RIA) methods of estimating rABP. The potency ratio of testicular ABP estimated by the two methods (RIA:SS-PAGE) was three times higher than this ratio in the epididymis in normal and hormonally treated animals. Due to differences in end points, these observations imply that these assays do not quantify the molecules in the same way in one or both of these tissues. The results indicate, however, that both assays are suitable for following rABP concentration in animals with altered hormonal states.
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PMID:Medroxyprogesterone acetate has opposite effects on the androgen binding protein concentrations in serum and epididymis. 622 25

This article reviews the seach for an effective, safe, and reversible method for the regulation of male fertility. Aside from vasectomy and gossypol (in China), no approach has reached the stage of large clinical trials. The World Health Organization (WHO) and the National Institutes of Child Health and Human Development (NICHD) are involved in a joint effort to prepare highly purified gossypol acetic acid to serve as an internationally available reference standard and have established a program for the synthesis and screening of analogues of gossypol and related compounds with a more favorable therapeutic profile. WHO and NICHD are also collaborating in a development program for synthesizing and screening longacting androgens with a longer duration of action than preparations currently available. It is unlikely that any new combinations of gestagens and androgens will be available before the end of the next decade, given the need for toxicological, mutagenic, and teratogenic evaluation. Successful use of luteinizing release hormone (LRH) agonists for male fertility control depends on the availability of a longacting delivery system to obviate the necessity of daily administration. In this case, a longacting androgen would have to be administered concomitantly to counter the decreased libido caused by the reduction of levels of endogenous androgens. Continued research is needed to elucidate the role of follicle-stimulating hormone (FSH) in the regulation of spermatogenesis, as is assessment of the longterm safety of active immunization with FSH preparations. Major progress has been made int he extraction, purification, and characterization of inhibin, as well as the development of in vivo and in vitro models for the evaluation of its effects and of radioimmunoassay procedures for its measurement. When the amino acid sequence of inhibin is known, it may be possible to prepare longer acting and more potent synthetic analogues. The possibility of developing FSH antagonists by chemical deglycosylation to selectively suppress spermatogenesis has also attracted interest. There has been no progress with regard to selective interference with sperm maturation in the epididymis. The success of an immunological approach to male fertility control depends on the identification, isolation, and purification of an epididymal constituent associated with sperm maturation in the epididymis.
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PMID:New contraceptives for men. What are the prospects? 641 30

Benomyl, a systemic fungicide, was administered to male Sprague-Dawley rats during the prepuberal, pubertal, or postpubertal stage of reproductive development. Animals received 5 or 10 daily treatments of 0, 125, 200, 250, 500, or 1000 mg benomyl/kg . d by gavage. Observations were made at selected intervals after exposure and included hematological parameters, body weight, tissue weights, total epididymal sperm counts, vas deferens sperm concentration, serum follicle-stimulating hormone ( sFSH ) levels, and testicular histology. Data presented here suggest that there is an age-related difference in sensitivity to benomyl. Animals that received benomyl treatments during prepuberty showed no significant treatment effects in tissue weights, total epididymal sperm counts, vas deferens sperm concentration, or sFSH . Animals that received at least 250 mg/kg . d during puberty or postpuberty showed one or more of the following effects: decreased testicular or epididymal weights, decreased epididymal sperm count, decreased vas deferens sperm concentrations, and/or testicular lesions. Histological examination of testicular tissue indicated a higher incidence of diffuse hypospermatocytogenesis in pubertal (20% of the treated animals) and postpubertal (40% of the treated animals) animals that were exposed to benomyl. These values were compared with those of the treated prepubertal animals, which had a 10% incidence of diffuse hypospermatocytogenesis , and with all of the control animals, which had no occurrences of this testicular lesion.
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PMID:Effect of benomyl on the reproductive development of male rats. 642 9


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