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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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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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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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Y. Tajima, K. Sakamaki, D. Watanabe, U. Koshimizu, T. Matsuzawa and Y. Nishimune

Summary. The effects of Steel–Dickie (Sld) mutations on testicular germ cell differentiation were investigated using experimental cryptorchidism and its surgical reversal in mutant, C57BL/6-Sld/+ and wild-type C57BL/6- +/+ mice. In Sld/+ cryptorchid testes the maintenance of undifferentiated type-A spermatogonia was impaired and their numbers decreased. In contrast, the proliferative activity of type-A spermatogonia in the cryptorchid testis of mutant mice appeared normal as judged by their progression through the cell cycle. Surgical reversal of cryptorchidism resulted in regenerative differentiation of mature germ cells in +/+ testes. However, the regenerative differentiation of type-A spermatogonia which remained in Sld/+ cryptorchid testes was strongly impaired, particularly at two steps of cellular differentiation, from type-A spermatogonia to intermediate or type-B spermatogonia and at meiotic division. Furthermore, in mutant mice, no significant recovery of testicular weight was observed after surgical reversal compared with +/+ mice.

Keywords: Sld mutation; testis; germ cell; Sertoli cell; cryptorchidism; mouse

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A. D. JOHNSON, W. R. GOMES and N. L. VanDEMARK

Summary.

Scrotal testes from control and unilaterally cryptorchid rats and rabbits and abdominal testes from animals unilaterally or bilaterally cryptorchid for 6 days were used in this study. Total cholesterol rose (P<0·05) in all abdominal testes as a result of increased (P<0·05) levels of esterified cholesterol. Fatty acids of the scrotal testes from unilaterally cryptorchid animals were only slightly changed by treatment. Changes in fatty acid esters in abdominal testes of unilaterally cryptorchid animals of both species were similar. These changes consisted of increases in most fatty acids with a chain length of 14, 16 and 18, both saturated and unsaturated. Abdominal testes of bilaterally cryptorchid rabbits differed from those of unilateral cryptorchids in that proportions of long chain fatty acids were more consistently increased in the former. Abdominal testes of the bilaterally cryptorchid rats also differed from the unilateral cryptorchids but less than in the rabbit. Differences in hormonal levels in the unilateral and bilateral cryptorchids are suggested as the most probable cause of difference in the abdominal testes of these groups.

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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. Sharpe

Summary. The specific testicular uptake in vivo of 125I-labelled hCG was compared in control adult rats and adult rats made bilaterally cryptorchid 5 weeks previously. Although a similar temporal pattern of uptake was observed in both groups, uptake of hCG by cryptorchid testes was reduced at all times after injection by up to 70%. The possible causes of this impairment were investigated. It could not be accounted for by differences in the rate of absorption or clearance of 125I-labelled hCG in the two groups. Therefore, because hCG-induced increase in the permeability of testicular capillaries is a crucial factor in determining hCG uptake by the testis, this change was compared in control and cryptorchid testes. Although hCG induced a characteristic increase in testicular capillary wall permeability in both groups, this change was temporally delayed in cryptorchid testes, and occurred after hCG values in the blood had fallen. Even when hCG had crossed the capillary wall into testicular interstitial fluid, its uptake into the testicular tissue was significantly lower in cryptorchid than in control testes. These changes probably account for the impairment of gonadotrophin uptake by the cryptorchid testis and have important implications with respect to the aetiology of Leydig cell changes in cryptorchidism.