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A. K. CHOWDHURY and E. STEINBERGER

Summary.

The influence of a cryptorchid milieu on the initiation of spermatogenesis was studied, utilizing the technique of transplantation of newborn rat testes into cryptorchid testes of adult hosts. The histological changes in the host and the transplanted testes were evaluated at various periods after transplantation. The transplant showed progressive growth and differentiation of the germ cells up to mid-pachytene stage within 30 days of transplantation into the cryptorchid testes. Thereafter, further progression of spermatogenesis did not occur and the germ cells gradually degenerated. Within 60 days, the seminiferous tubules in the transplant were lined by a layer of Sertoli cells and were comparable in appearance to the host tissue. In another group of animals where the cryptorchid testis was returned to the scrotum at the time of transplantation, both initiation and completion of spermatogenesis were observed. The results indicate that a cryptorchid milieu does not interfere with the initiation of spermatogenesis, but prevents its progression and maintenance.

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R. M. LIPTRAP and J. I. RAESIDE

Summary.

Urinary excretion of dehydroepiandrosterone (DHA) and oestrogens was determined in five bilaterally cryptorchid boars and four unilaterally cryptorchid boars. Similar determinations were carried out in two boars made cryptorchid through surgery. The DHA and oestrogen values for the cryptorchid animals were comparable to normal boars of a similar age. These results suggest that the cryptorchid testes of the boar are capable of producing normal amounts of testicular steroid hormones.

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Jane N. Scott, H. Ira Fritz and F. Nagy

Summary. Adult male opossums, Didelphis virginiana, were rendered hemicryptorchid for 35 days. The cryptorchid testis exhibited a significant reduction in weight, while the contralateral testis had a compensatory weight gain compared with testes of untreated animals. Histological changes in the cryptorchid testis included fibrosis of the tunica propria, involution of the seminiferous tubules and an apparent increase in the interstitial tissue. Many seminiferous tubules were empty and germinal cells were absent. Some Sertoli cells persisted, but the cytoplasm was vacuolated. Cryptorchid testes were characterized by mononuclear leucocytic invasion around the tubules, and some eosinophils were observed. Cryptorchidism in the opossum may induce a reaction similar to experimental orchitis.

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A. K. Susheela and A. Kumar

Summary. Fluoride was orally administered to rabbits at 10 mg NaF/kg body weight for 18 or 29 months. The animals were then killed and the structure of the testis, epididymis and vas deferens studied under light and scanning electron microscopes. In animals treated for 29 months, the spermatogenic cells in the seminiferous tubules were disrupted, degenerated and devoid of spermatozoa. In animals treated for 18 or 29 months, loss of cilia on the epithelial cells lining the lumen of the ductuli efferentes of the caput epididymidis and of stereocilia on the epithelial cells lining the lumen of the vas deferens was observed. In some regions of the epithelial lining of the lumen of the ductuli efferentes and vas deferens, the boundaries of the cells were not clear and appeared to be peeled off. Mucus droplets were abundant in the vas deferens of control animals, but absent in both the treated groups. Spermatogenesis ceased only in animals treated for 29 months. The difference in the structural changes observed in the testes of the 2 treated groups may have been due to the blood–testis barrier. It is concluded that ingestion of high concentrations of fluoride has harmful effects on the male reproductive system.

Keywords: fluoride toxicity; spermatogenesis; ductuli efferentes; rabbit

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T. Jahnsen, B. Karpe, H. Attramadal, M. Ritzén and V. Hansson

Summary. Cryptorchidism was associated with increased responsiveness of the isoproterenol-sensitive adenylate cyclase in membrane particles from rat testis. Abdominal testes from uni- and bilaterally cryptorchid rats showed the same activities. The change in isoproterenol-responsive adenylate cyclase was independent of the age at which the animals were made cryptorchid. The isoproterenol response was maximal 3–4 weeks after the rats were made cryptorchid. By 2–3 months after orchidopexy the isoproterenol response in the rat testis had decreased to normal control values.

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N. Leader-Williams

Summary. In a sample of reindeer from South Georgia, 4 males were abnormal in that 1 had bilateral cryptorchid testes, 2 each had 1 cryptorchid testis and 1 had a vestigial testis. The antlers of the cryptorchid males were small, but the antler cycle itself was hardly affected.

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Lais Cavalca Cardoso, Aline Rosa Nascimento, Carine Royer, Catarina Segreti Porto and Maria Fatima Magalhaes Lazari

We have previously shown that the rat testis and vas deferens contain high levels of the relaxin receptor, RXFP1. The present study was undertaken to determine the expression of relaxin in these tissues, and the effect of exogenous relaxin on Sertoli cell proliferation and on the mRNA levels of some proteins that may contribute to epithelial secretion and tissue reorganization in the vas deferens. Relaxin mRNA levels in testis and vas deferens were much lower than in the prostate. Sertoli cells seem to be an important source of relaxin mRNA in testis. Relaxin immunoreactivity was detected in the seminiferous epithelium but not in the interstitial compartment. The relaxin precursor was expressed in the vas deferens, and relaxin immunoreactivity was detected in apical cells of the vas deferens. Castration, but not treatment with the anti-estrogen ICI 182,780, dramatically reduced relaxin mRNA levels in the prostate and vas deferens, and this effect was prevented by testosterone. Rxfp1 mRNA levels in the vas deferens and prostate were not affected by castration or treatment with ICI 182,780. Exogenous relaxin increased the incorporation of 3H-thymidine in cultured Sertoli cells, and treatment of the vas deferens with 100 ng/ml relaxin increased the mRNA levels for the cystic fibrosis chloride channel (cystic fibrosis transmembrane regulator) about three times, and doubled mRNA levels for the inducible form of nitric oxide synthase and metalloproteinase 7. These results suggest that locally produced relaxin acts as an autocrine or paracrine agent in the testis and vas deferens to affect spermatogenesis and seminal fluid composition.

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G. P. Risbridger, A. E. Drummond, J. B. Kerr and D. M. de Kretser

Summary. There was a significant (P < 0·05) and consistent increase in the potency of steroidogenic stimulatory activity (testosterone production by purified Leydig cells in vitro) in testicular interstitial fluid of the cryptorchid compared to the scrotal testis from 1 to 4 weeks after the induction of unilateral cryptorchidism. In contrast, the level of mitogenic activity ([3H]thymidine incorporation into 3T3 cells) was not significantly different between interstitial fluid from cryptorchid and scrotal testes for up to 4 weeks after surgery. These results indicate that the steroidogenic activity and the mitogenic activity are due to different, as yet unidentified, factors in testicular interstitial fluid.

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Carol G. Swan and N. L. Poyser

Summary. The endogenous concentrations of three PGs in the vas deferens of rabbits and rats were low (5–50 ng/100 mg tissue), although PGE-2 and PGF-2α were present in greater quantities than 6-keto-PGF-1α. Homogenates of rat and rabbit vas deferens synthesized these three PGs in large quantities during a 90 min incubation period. PGE-2 was the major PG synthesized by the rat vas deferens, followed by PGF-2α and 6-keto-PGF-1α. PG production by the rabbit vas deferens was lower than in the rat and PGF-2α was the major PG formed.

None of the prostanoids tested (PGE-1, PGE-2, PGD-2, ICI 79939, ICI 81008 (fluoprostenol), 9,11-epoxymethano PGH-2, and 11,9-epoxymethano PGH-2) in concentrations up to 1–20 μg/ml altered the tone of the rabbit or rat vas deferens. PGI-2 was more potent than PGE-2 or PGF-2α in potentiating responses of the rabbit vas deferens to noradrenaline but was less potent than PGF-2 or PGE-1 in inhibiting responses to field stimulation. No consistent effects of these three PGs on responses of the rat vas deferens to noradrenaline administration were observed. PGE-2 and PGE-1, but not PGI-2, had only a small inhibitory effect on the responses of the rat vas deferens to field stimulation. None of the other prostanoids tested affected the responses of the vas deferens to noradrenaline or to field stimulation in either species. It is concluded that, while PGs may not directly affect the tone of the vas deferens, they may affect the contractility of the vas deferens by pre-junctional actions in the rabbit and rat, and by post-junctional actions in the rabbit. These actions of PGs (confined to PGE-2, PGF-2α and PGI-2) may influence sperm transport along the vas deferens.

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B. Jégou, A. O. Laws and D. M. de Kretser

Summary. Cryptorchidism for 28 or 10 days resulted in a severe disruption of spermatogenesis (assessed histologically or by fertility tests), Sertoli cell function (assessed by seminiferous tubule fluid production after efferent duct ligation, ABP levels, binding of 125I-labelled FSH to testis homogenates and serum FSH levels) and Leydig cell function (assessed by serum LH and testosterone levels, in-vitro testosterone production, binding of 125I-labelled hCG). Orchidopexy after 28 days of cryptorchidism resulted in a poor recovery of spermatogenesis since the majority of tubules were lined by Sertoli cells and a few spermatogonia. No recovery occurred in the indicators of Sertoli and Leydig cell function.

Orchidopexy after 10 days of cryptorchidism also resulted in a poor recovery of spermatogenesis, with a few animals showing partial recovery after 6 months. No recovery occurred in seminiferous tubule fluid production but partial recovery occurred in ABP content and production rate. Serum FSH, LH levels and in-vitro testosterone production by the testis remained elevated and did not change from the values found during cryptorchidism.

Fertility testing at 6 months revealed a small number of rats in which fertility was restored although the number of embryos was lower than in controls. In this group of animals there was a significant improvement in a number of indicators of Sertoli cell and Leydig cell function. These data provide further evidence to link the changes in Sertoli cell and Leydig cell function to the germ cell complement present in the testis.