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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A model for the study of testicular function in experimental uremia induced by subtotal nephrectomy in mature male rats is described. Glomerular filtration rate was reduced by 87%, resulting in stable uremia for up to 13 weeks with characteristic biochemical changes and reduction in weight of testes, prostate, seminal vesicles, and epididymis but not of heart, liver, spleen, or epididymal fat-pads in comparison with pair-fed and sham-operated, ad libitum-fed littermate controls. Basal serum LH, FSH, and testosterone were reduced and PRL levels increased in chronic uremic rats compared with pair-fed and sham-operated controls. Intratesticular and peripheral venous testosterone levels were reduced by 73-85%, whereas spermatic vein testosterone levels were reduced by 47% suggesting a reduction in blood flow to the uremic rat testis. Sensitivity of uremic Leydig cells to human CG stimulation was normal to increased both in vivo and in vitro without changes in LH receptor affinity or numbers. Fertility was markedly impaired in uremic rats but was restored to normal by either human CG or testosterone treatment. Spermatogenesis was minimally depressed after up to 3 months of uremia. These studies suggest that this experimental paradigm is a suitable model for studying the pathogenesis of early changes in uremic hypogonadism. The predominant early changes of uremic hypogonadism are due to central defects in regulation of pituitary LH secretion with consequent testicular and peripheral hypoandrogenism but initial preservation of spermatogenesis.
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PMID:Testicular function in experimental uremia. 393 Feb 20

It is well documented that long-term diabetes mellitus results in numerous deleterious consequences. However, considerable controversy exists concerning male reproductive function in diabetes. The purpose of this investigation was to study several endocrine parameters in diabetic male rats with emphasis on Sertoli cell function. Male Wistar rats were injected with streptozotocin and then either left untreated for 30 days or injected with insulin so as to prevent spillover of glucose into the urine. These two groups were compared with control animals that had only been injected with the vehicle for streptozotocin. Semi-starved control animals were included to determine if any of the potential endocrine alterations were related to body weight changes which occur in streptozotocin-injected rats. It was found that FSH, LH, PRL, and GH serum levels were reduced in diabetic animals. Only FSH was restored to normal by insulin injections. The testis, seminal vesicle, and epididymis weights were all reduced in diabetic animals. Insulin injections raised all organ weights; however, only testis weights were fully restored. Levels of epididymal ABP activity were found to be higher in diabetic animals when expressed per mg protein. Similar patterns of organ weight loss and hormonal alterations were observed in semi-starved rats. However, epididymal levels of ABP activity were unaffected by the semi-starved condition. While weight loss should be taken into consideration when interpreting cause and effect relationships in streptozotocin-treated animals, epididymal ABP levels appear to be well correlated with the altered metabolic state characteristic of diabetes.
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PMID:Sertoli cell function in diabetic, insulin-treated diabetic, and semi-starved rats. 621 25

Cytoproterone acetate (CPA) type antiandrogens have been found to inhibit all androgen-dependent function (also reproductive ability) in man and male experimental animals. In animals a CPA dose can be established which reduces spermatogenesis but leaves hormone regulation unchanged. It is not possible to selectively affect epididymal sperm maturation. Initial clinical experience with high-dosage CPA therapy for fertility inhibition was gained from patients with sex deviations. Oral administration of 100-300 mg CPA daily caused high degree of oligospermia within a few weeks; whether longterm therapy (1 1/2-2 years) leads to desensitization and subsequent increase of gonadotropins and androgens with recovered fertility has not yet been established. Sex drive is strongly affected by high-dosage therapy, hence not desirable for male fertility control. A World Health Organization study used a low-dosage daily oral CPA intake of 5-20 mg over a period of 12-26 weeks. Men under 30 years of age tolerated this daily use without side effects; men over 35 years complained of diminished libido and potency. These CPA dosages reduced sperm quality to subfertile values; sperm count, shape, and motility were affected but no azoospermia was achieved. In vitro and in vivo sperm migration is strongly affected. All somatic and psychosexual changes are reversible. In contrast to animal studies oral use of 10 mg CPA daily modifies endocrinologic processes in man. There is a decrease in FSH and LH synthesis and release; this demonstrates a stronger gestagen effect than the antiandrogen effect of CPA. There is an even greater reduction in plasma testosterone and dihydrotestosterone levels. CPA also modifies testicular androgen production; changes in spermatogenesis can be attributed to a reduced androgen output and to a ect CPA effect on the tubules. A distinct modification of spermatogenesis and posttesticular sperm maturation processes cannot be demonstrated in the dosage range studied. Current studies do not allow a conclusive evaluation of the applicability of CPA for fertility control in men. Longterm studies with smaller CPA dosages are needed.
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PMID:[Modification of fertility of the male by antiandrogens]. 621 27

Cyproterone acetate was administered every 2 days from 1 to 39 days of age to male mice which were killed 24 h or 20 days after the last injection. Cyproterone acetate caused a significant reduction in the relative weights of the epididymis, vas deferens, seminal vesicle and preputial gland, which was still evident at 60 days after birth. Testicular and epididymal androgens (testosterone and dihydrotestosterone) and circulating LH and FSH concentrations were equal to or higher than those of controls at 60 days. Cyproterone acetate did not inhibit spermatogenesis but all males were infertile. The results suggest that the peripheral effects of testosterone are necessary, during early stages of sexual maturation, in order to obtain subsequent full development of the accessory sex organs.
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PMID:Sexual maturation in male mice treated with cyproterone acetate from birth to puberty. 623 74

Subcutaneous injections of testosterone propionate to adult male rats at a dose of 2.5 or 10 mg/kg body weight, 3 times per week for 7 weeks, resulted in a 75% reduction in serum LH and more than 50% reduction in intratesticular testosterone concentration, but serum FSH levels remained unchanged. The free -SH content, measured as iodo[14C]acetamide binding, increased by 70-100% in testicular sperm heads after suppression of testicular testosterone, and by 25-30% in caput epididymal sperm heads but was decreased by 70-80% in cauda epididymal sperm heads. These results demonstrate an alteration in the oxidative state of sperm nuclear basic proteins, suggesting incomplete nuclear maturation. These changes may be specific for the suppression of intratesticular testosterone, thus illustrating the androgen dependency of sperm head maturation. The contrast effects noted between the iodo[14C]iodoacetamide binding by the caput and the cauda epididymal sperm heads indicate that testosterone propionate treatment may affect the mechanisms regulating the oxidation of the sulphydryl residues in sperm heads during epididymal transit. This alteration may not directly relate to the tissue androgen concentrations.
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PMID:Alteration of free sulphydryl content of rat sperm heads by suppression of intratesticular testosterone. 636 92

The influence of thyroxine treatment on key enzymes involved in the glycolytic and HMP shunt pathways was studied in the caput, corpus and cauda epididymides of pubertal rats, and related to the serum hormone profile. The activity of 6-phosphofructokinase and pyruvate kinase was significantly increased in all 3 segments of the epididymis, but the HMP shunt pathway was suppressed. Thyroxine treatment was found to depress the serum levels of testosterone, LH and FSH, although an increase in prolactin levels was observed. Withdrawal of hormone treatment resulted in the restoration of normal activity of 6-phosphofructokinase and pyruvate kinase and restoration of normal serum hormone levels. However, the activity of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase increased following withdrawal of treatment. It is concluded that hyperthyroidism exerts an influence on epididymal enzymes involved in carbohydrate metabolism.
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PMID:Effect of thyroxine treatment on epididymal carbohydrate metabolism in the pubertal rat. 641 29

The influence of thyroidectomy on key epididymal enzymes of the Embden-Meyerhof and pentose phosphate pathway have been studied in pubertal and adult animals in relation to the serum hormone profile. Age related differences in the response of epididymal segments were observed with respect to hexokinase activity, although the other 2 key enzymes of the Embden-Meyerhof pathway (6-PFK and PK) were suppressed in all regions of the epididymis in both pubertal and adult rats. The enzymes involved in the pentose phosphate pathway (G-6-PDH and 6-PGDH) remained unaltered. The serum hormone profile revealed that while FSH and testosterone titres were reduced, LH and Prl were unaltered. Replacement of T4 in thyroidectomized animals maintained serum hormone levels and the activities of the enzymes studied at control levels. It is inferred that thyroid hormones may be one part of a complex mechanism that controls carbohydrate metabolism in the epididymis.
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PMID:Influence of hypothyroidism on epididymal enzymes involved in carbohydrate metabolism. Studies in pubertal and adult rats. 641 30

The present study was undertaken to evaluate the endocrinologic and spermatogenic effects of carbon disulfide (CS2) exposure in the rat. Adult, male rats were exposed to either 600 ppm CS2 or filtered air for 6 hr/day for 5 days/week for 10 weeks. One week prior to exposure and then at Weeks 1, 4, 7, and 10, males were placed with ovariectomized, hormonally primed females, and copulatory behaviors were scored. Fifteen minutes postcopulation, the female was killed and the ejaculate was recovered from the excised uterine tract along with the semen plug. Sperm counts, sperm motility, and morphology were determined. A blood sample was obtained for analyses of testosterone, follicle-stimulating (FSH), and luteinizing hormone (LH). At the end of the 10th week, five animals in each group were challenged with either human chorionic gonadotropin (HCG, 50 IU/animal, iv) or gonadotropin-releasing hormone (GnRH, 100 ng/animal, iv), and the testosterone or gonadotropin responses were monitored over time. Animals were subsequently killed with one epididymis and testis processed for histology and a sperm count determined from the other epididymis. Analysis revealed that CS2 exposure produced significant alterations in copulatory behavior and a decrease in ejaculated sperm counts by the fourth and seventh weeks of exposure, respectively. No endocrinologic alterations were observed. Moreover, caudal epididymal sperm counts were not depressed and the testes appeared histologically normal. These data suggest that CS2 does not exert a direct effect on the testes, but rather may interfere with the processes regulating sperm transport and ejaculation.
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PMID:An evaluation of the copulatory, endocrinologic, and spermatotoxic effects of carbon disulfide in the rat. 642 68

This study was designed to determine the effects of a short episode of testicular heating (43 degrees C for 15 min) on spermatogenesis and Sertoli and Leydig cell function. Rats killed at intervals up to 156 days after heating were assessed by histological examination, and by measurement of serum FSH and LH, and by tests of Sertoli cell function consisting of fluid production, androgen binding protein (ABP) content of the ligated and unligated tests, together with the binding of [125I]FSH. Leydig cell function was assessed by in vitro testosterone production, serum testosterone levels and [125I]hCG binding to testes homogenates. Testis weight declined 7 days after heating to 70% of control and remained lower until 82 days, whereas epididymal weight did not decrease significantly until 26 days and also recovered by 82 days. Fluid production was significantly lower in heated testes at 26 days and returned to normal at 56 days. ABP production measured as the difference between the ABP content of ligated and unligated testes was significantly reduced at 14 and 26 days, but subsequently recovered. Serum FSH levels were significantly elevated from 14-26 days in the heat treated group and the binding of [125I]FSH was reduced at 26 days post-heating. Basal and stimulated in vitro T production was significantly increased in the heat-treated testes at 14 days and subsequently returned to normal whilst [125I]hCG binding was significantly lower in the heat-treated testes from 7-26 days. Serum T and LH did not alter significantly during the study. Primary spermatocytes and young spermatids were the most heat sensitive germ cell type and a reduction in spermatogenesis was noted from 7 to 26 days, although recovery appeared complete by 56 days and thereafter. These results demonstrate that the transient spermatogenic disruption induced by heating is accompanied by significant alterations in Sertoli and Leydig cell function which are identical to those produced in other models of spermatogenic dysfunction. The results suggest that the duration of these changes appears to correlate closely with alterations occurring in the germ cell compartment.
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PMID:Changes in testicular function induced by short-term exposure of the rat testis to heat: further evidence for interaction of germ cells, Sertoli cells and Leydig cells. 643 36

A dose-dependent increase in body length and weight can be induced in Snell dwarf mice by human, porcine and bovine growth hormones, ovine prolactin, bovine TSH, T4 and T3, and to a lesser extent by insulin. In contrast, porcine FSH, equine LH, testosterone, oestradiol and glucagon influenced neither body length nor weight. Beside body length and weight, the weight of many organs is stimulated by hormonal treatment. GH, T4 and T3 have a rather similar spectrum of effects, with exceptions for the skinfold and epididymal fat-pads. LH had no effect, but in contrast FSH had a strong effect on the seminal vesicles and a less pronounced one on the testis. Oestradiol induced a marked enlargement of the uterus, whereas testosterone increased the weights of the kidneys and seminal vesicles. The main action of insulin is probably localized on body fat. Glucagon, however, did not stimulate organ growth. These data illustrate again the complexity of hormonal regulation of growth.
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PMID:The effects of pituitary, thyroid, pancreatic and sexual hormones on body length and weight and organ weights of Snell dwarf mice. 672 29


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