Cytoskeletal activities mediated by actin filaments facilitate the production of spermatozoa. Actin filaments have been identified in the Sertoli cell and germ cells but since localization data is incomplete, a major objective of this proposal is to undertake a comprehensive localization of actin within Sertoli cells and germ cells. To obtain data related to the functional activity of actin filaments, the actin filament disrupting agent--cytochalasin D--will be injected intratesticularly. A dramatic effect of cytochalasin D is to disrupt actin filaments in peritubular myoid cells. It is noted that within hours of cytochalasin D injection sperm are released normally in the appropriate stage but do not move down the seminiferous tubule. We propose studies using cytochalasin D to determine the role of myoid cells in sperm transport. Cytochalasin D prevents formation of the actin filament bundles (ectoplasmic specialization) of the Sertoli cell which face the newly elongating spermatid. The consequence of disruption of the ectoplasmic specialization on germ cell orientation and indention into the Sertoli cell will be studied. Cytochalasin D also prevents formation of the actin filaments surrounding the tubulobulbar complex--a structure which is implicated in sperm release and elimination of excess spermatid cytoplasm. The consequence of disruption of tubulobulbar complexes will be studied. Another effect of cytochalasin D is to inhibit migration of spermatocytes through the Sertoli cell barrier and to disrupt ectoplasmic specialization which lines the Sertoli cell barrier. The consequence of disruption of the ectoplasmic specialization in prepubertal animals just forming a Sertoli cell barrier as well as in the maintenance of the barrier in the adult will be studied with transmission electron microscopy and also freeze-fracture to determine if actin is involved with the formation or regulation of occluding junctions. Cytochalasin D also has a rapid effect on intercellular bridges between spermatids, causing them to open. The intercellular bridges are remnants of the actin-containing contractile ring and show 5-7 nm filaments. It has been proposed that synchronization of germ cell development occurs through bridges. Collectively, the processes to be examined are fundamental to the successful maturation and transport of germ cells in all mammals including man and their selective disruption will provide valuable information on the normal mechanisms of sperm production as well as potential insights into pathologies which affect spermatogenesis by similar mechanisms.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
1R01HD020300-01A1
Application #
3318286
Study Section
Reproductive Biology Study Section (REB)
Project Start
1986-04-01
Project End
1989-03-31
Budget Start
1986-04-01
Budget End
1987-03-31
Support Year
1
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Southern Illinois University Carbondale
Department
Type
Schools of Arts and Sciences
DUNS #
939007555
City
Carbondale
State
IL
Country
United States
Zip Code
62901
Ren, H P; Russell, L D (1991) Clonal development of interconnected germ cells in the rat and its relationship to the segmental and subsegmental organization of spermatogenesis. Am J Anat 192:121-8
Meistrich, M L; Trostle-Weige, P K; Russell, L D (1990) Abnormal manchette development in spermatids of azh/azh mutant mice. Am J Anat 188:74-86
Russell, L D; Ren, H P; Sinha Hikim, I et al. (1990) A comparative study in twelve mammalian species of volume densities, volumes, and numerical densities of selected testis components, emphasizing those related to the Sertoli cell. Am J Anat 188:21-30
Kurohmaru, M; Sinha Hikim, A P; Mayerhofer, A et al. (1990) Golden hamster myoid cells during active and inactive states of spermatogenesis: correlation of testosterone levels with structure. Am J Anat 188:319-27
MacGregor, G R; Russell, L D; Van Beek, M E et al. (1990) Symplastic spermatids (sys): a recessive insertional mutation in mice causing a defect in spermatogenesis. Proc Natl Acad Sci U S A 87:5016-20
Russell, L D; Bartke, A; Goh, J C (1989) Postnatal development of the Sertoli cell barrier, tubular lumen, and cytoskeleton of Sertoli and myoid cells in the rat, and their relationship to tubular fluid secretion and flow. Am J Anat 184:179-89
Hikim, A P; Amador, A G; Bartke, A et al. (1989) Structure/function relationships in active and inactive hamster Leydig cells: a correlative morphometric and endocrine study. Endocrinology 125:1844-56
Hikim, A P; Amador, A G; Klemcke, H G et al. (1989) Correlative morphology and endocrinology of Sertoli cells in hamster testes in active and inactive states of spermatogenesis. Endocrinology 125:1829-43
Russell, L D; Saxena, N K; Turner, T T (1989) Cytoskeletal involvement in spermiation and sperm transport. Tissue Cell 21:361-79
Mayerhofer, A; Sinha Hikim, A P; Bartke, A et al. (1989) Changes in the testicular microvasculature during photoperiod-related seasonal transition from reproductive quiescence to reproductive activity in the adult golden hamster. Anat Rec 224:495-507

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