The secretory and absorptive functions of the epididymis appear to play an important role towards sperm maturation. This proposal is aimed at defining which epididymal regions secrete and absorb amino acids into and out of its lumen respectively. Initially, the concentrations of different amino acids will be estimated in the luminal fluid of the testis (seminferous tubule, rete testis), in different epididymal regions (proximal caput, distal caput, corpus, cauda and ductus deferens), in spermatozoa and in blood plasma. Then, utilizing the technique of stopped-flow split- drop microperfusion, the secretion of amino acids will be determined for each epididymal region (proximal and distal caput, corpus and cauda). Further experiments will be directed towards understanding whether the luminal fluid environment plays and important role in the secretion of amino acids into the lumen of different epididymal regions. In this instance, we will determine whether sodium ions, pH, energy-dependence or testicular factors play a role. The absorption of L-glutamate and L-alanine (those amino acids found to decrease in luminal fluid concentration from caput to cauda) from the lumen of different epididymal regions (caput, corpus and cauda epididymidis) will then be studied using the stopped-flow split droplet microperfusion technique. The specificity and sodium-dependence for each amino acid transport system will be studied in detail. The secretion and absorption of different micromolecules, organic solutes and ions produce a specialized microenvironment which appears to be important for sperm maturation, development and survival. A further understanding of the complex interaction between the epididymal epithelium, microenvironment and spermatozoa will provide information fundamental to the development of a male contraceptive and treatment of certain forms of male infertility.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD018257-04A1
Application #
3315254
Study Section
Reproductive Biology Study Section (REB)
Project Start
1983-12-01
Project End
1990-06-30
Budget Start
1987-07-01
Budget End
1988-06-30
Support Year
4
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Virginia
Department
Type
Schools of Medicine
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Gallagher, B C; Rudolph, D B; Hinton, B T et al. (1998) Differential induction of gamma-glutamyl transpeptidase in primary cultures of rat and mouse hepatocytes parallels induction during hepatocarcinogenesis. Carcinogenesis 19:1251-5
Rudolph, D B; Hinton, B T (1997) Stability and transcriptional regulation of gamma-glutamyl transpeptidase mRNA expression in the initial segment of the rat epididymis. J Androl 18:501-12
Lan, Z J; Palladino, M A; Rudolph, D B et al. (1997) Identification, expression, and regulation of the transcriptional factor polyomavirus enhancer activator 3, and its putative role in regulating the expression of gamma-glutamyl transpeptidase mRNA-IV in the rat epididymis. Biol Reprod 57:186-93
Hinton, B T; Palladino, M A; Rudolph, D et al. (1996) The role of the epididymis in the protection of spermatozoa. Curr Top Dev Biol 33:61-102
Ricker, D D; Chamness, S L; Hinton, B T et al. (1996) Changes in luminal fluid protein composition in the rat cauda epididymidis following partial sympathetic denervation. J Androl 17:117-26
Hinton, B T; Palladino, M A; Rudolph, D et al. (1995) The epididymis as protector of maturing spermatozoa. Reprod Fertil Dev 7:731-45
Hinton, B T; Palladino, M A (1995) Epididymal epithelium: its contribution to the formation of a luminal fluid microenvironment. Microsc Res Tech 30:67-81
Palladino, M A; Hinton, B T (1994) Developmental regulation of expression of multiple gamma-glutamyl transpeptidase mRNAs in the postnatal rat epididymis. Biochem Biophys Res Commun 198:554-9
Palladino, M A; Hinton, B T (1994) Expression of multiple gamma-glutamyl transpeptidase messenger ribonucleic acid transcripts in the adult rat epididymis is differentially regulated by androgens and testicular factors in a region-specific manner. Endocrinology 135:1146-56
Palladino, M A; Laperche, Y; Hinton, B T (1994) Multiple forms of gamma-glutamyl transpeptidase messenger ribonucleic acid are expressed in the adult rat testis and epididymis. Biol Reprod 50:320-8

Showing the most recent 10 out of 15 publications