ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02801.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02802.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02803.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02804.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02805.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02806.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Summary.Prolonged darkness caused a fall in testicular 17 β‐hydroxysteroid dehydrogenase (17β‐HSD) activity and diminished spermatogenesis, serum levels of gonadotropins, testosterone and α2u‐globulin.Administration of α2u‐globulin at a dose of 1.5 mg rat−1per day for 7 days after 68 days of light deprivation, reversed the 17β‐HSD activity and serum levels of gonadotropins, testosterone and α2u‐globulin, while spermatogenesis was restored to normal.The animals kept in prolonged darkness for 68 days and then received saline (7 days in light‐dark cycle, 14 L: 10 D), showed no significant changes of testicular activity, serum levels of gonadotropins, testosterone and α2u‐globulin, when compared with dark‐exposed animals (68 days) receiving rabbit serum (7 days in light‐dark cycle, 14 L: 10 D). These results suggest that α2u‐globulin plays an important role in testicular function in dark‐exposed rats by inducing gonadot

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02807.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Summary.The effect of temperature fluctuations which cryopreserved spermatozoa may undergo during routine shipping and handling was evaluated in sperm frozen with two cryoprotectants. Sperm frozen in TEST‐yolk buffer maintained motility better than those frozen in glycerol solution in all studies. Sperm motility was significantly compromised in samples stored more than one day in dry ice, regardless of the cryoprotectant, and more than two days in a liquid nitrogen shipping dewar if frozen in glycerol solution. Sperm motility was not compromised following exposure to room temperature for up to 3 min if TEST‐yolk buffer was used as the cryoprotectant, but was compromised following 1 min exposure using glycerol cryoprotectant. This study describes the limits of non‐ideal conditions that spermatozoa may undergo during shipping and handling, and demonstrates the effects of the cryoprotectant on those l

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02808.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Summary.The aim of the present study was to determine the interaction between substance P (SP) and arginine‐vasopressin (AVP) on basal and LH‐stimulated testosterone production by Leydig cells isolated from hamsters kept under long or short days (LD‐hamsters, SD‐hamsters, respectively). SP inhibited the testosterone production of Leydig cells, its effect being more pronounced in the case of LH‐stimulated steroidogenesis in LD‐hamsters. Similarly, the addition of AVP to the culture medium resulted in a diminution of basal, as well as LH‐stimulated testosterone secretions. When Leydig cells were co‐incubated with SP (10−7M) and AVP (10−7M), a strong inhibition of the testosterone production by 50–60% was established in LD‐animals. However, even within the experimental circumstances in SD‐hamsters, the modulation of testosterone production by SP and AVP was evident. The reported results suggest that there is an interference of two regulatory pathways, namely photoperiodic dependence and paracrine control of testicular st

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02809.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Summary.Glycosidases secreted by the epididymis become bound to the surface of spermatozoa during their transit through the epididymal duct. They are believed to play a role in mammalian fertilization. In the present report, we demonstrate that β‐glucuronidase binds to the surface of ejaculated human spermatozoa with high affinity and in a saturable manner. The binding is Ca2+‐independent, inhibited by either mannose‐6‐phosphate, phosphomannan fragments from the yeastHansenula holstiiand α‐mannosidase from theDictyostelium discoideum, suggesting that phospho‐mannosyl receptors are involved in the recognition of the enzyme. The catalytic site of the enzyme is not involved in the binding. The localization of the β‐glucuronidase binding‐sites is restricted to the surface of the sperm head. These results suggest that the spermatozoa could be the target for glycosidases present in

ISSN:0303-4569    

DOI:10.1111/j.1439-0272.1996.tb02810.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY