Archive for the 'Sperm' Category

11 Feb

Selenoprotein P Is Required for Mouse Sperm Development: DISCUSSION

This study demonstrates that spermatozoa from males with targeted deletion of the Sepp1 gene that are fed normal dietary levels of selenium progressively develop a set of structural defects during spermiogenesis and after testicular maturation that result in male infertility. Feeding supplemental dietary selenium to Sepp1~/~ males does not reverse infertility or prevent the development […]

09 Feb

Selenoprotein P Is Required for Mouse Sperm Development: RESULTS

Chronological Development of Flagellar Defects in Spermatozoa of Sepp1 _/~ Mice Light and electron microscopic comparisons of testicular and epididymal spermatozoa of wild-type and Sepp1~/~ mice revealed a progressive development of severe flagellar defects in the null animals. Null animals between 2 and 12 mo of age exhibited identical sperm defects. Phase-contrast images of testicular […]

07 Feb

Selenoprotein P Is Required for Mouse Sperm Development: MATERIALS AND METHODS

Animals Care and use of animals conformed to National Institutes of Health guidelines for humane animal care and use in research, and all animal protocols were approved by the Vanderbilt Institutional Animal Care and Use Committee. Mice were housed in an Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC) approved facility on […]

05 Feb

Selenoprotein P Is Required for Mouse Sperm Development: INTRODUCTION

Selenium is a dietary micronutrient required by mammalian tissues and is essential for the maintenance of normal spermatogenesis and male fertility. Early studies demonstrated that selenium is incorporated into mouse and rat spermatogenic cells and that, in selenium-replete adult rats, the testes and spermatozoa contained higher selenium concentrations than other major organs. It was also […]

18 Jan

Requirements for Glucose Beyond Sperm Capacitation: DISCUSSION

The role of metabolic substrates in mammalian sperm capacitation and fertilization has been studied for several decades. The early observation that rabbit sperm display increased energy demands during capacitation indicated that such pursuits might be of practical as well as scientific interest. However, the literature remains unclear as to whether glucose is required for fertilization […]

16 Jan

Requirements for Glucose Beyond Sperm Capacitation: RESULTS

To determine whether glucose affected any aspect of IVF in the murine model system, spermatozoa were capacitated with different concentrations of glucose, and then IVF was performed in drops containing that same concentration of glucose. A clear concentration response was seen regarding the effect of glucose on the percentage of eggs fertilized, with increasing concentrations […]

14 Jan

Requirements for Glucose Beyond Sperm Capacitation: MATERIALS AND METHODS

Definitions and Guidelines Because different endpoints have been utilized in previous studies to assess capacitation and fertilization, it is important to introduce strict definitions when trying to elucidate potential roles for substrates such as glucose in these different processes. For the present investigation, capac-itation will be strictly defined as the process of functional maturation that […]

12 Jan

Requirements for Glucose Beyond Sperm Capacitation: INTRODUCTION

Unlike the sperm of animals that utilize external fertilization, mammalian sperm has evolved to depend on metabolic substrates found in the extracellular environment. However, great differences exist between species in how they respond to individual substrates. For example, glucose is believed to inhibit the capacitation of bovine sperm but to promote the capacitation of murine […]

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