Thesis Abstract and Dissertation Abstracts

The 1980s heralded the discovery and identification of extra-pituitary sources of the neurohypophysial hormone oxytocin in several animal species. The presence, location and biosynthesis of significant amounts of oxytocin from the ovarian corpus luteum was followed by the immunocytochemical demonstration of an oxytocin-like peptide in the interstitial (Leydig) cells. Testosterone is biosynthesized in situ by Leydig cells which comprise up to 80% of the testicular intertubular cell population. Thus, the question arises whether a Leydig cell oxytocin-like peptide is also synthesized de novo or is taken up and stored by the cell from some other intra- or extra-gonadal source. To determine if Leydig cells manufacture an oxytocin-like peptide, a known stimulator of oxytocin production in ovarian granulosa cells was utilized in the present study. Interstitial cells were isolated using a multistep procedure that employed vascular perfusion, enzymatic dissociation, centrifugal elutriation and Percoll gradient centrifugation. Purified Leydig cells were incubated with 100 ng LH for 24 hours in the presence of increasing concentrations of ascorbate. Sample supernatants were extracted, concentrated under vacuum and reconstituted with acidified absolute ethanol. Samples were analyzed using high performance liquid chromatography (HPLC) with electrochemical detection and known concentrations of an oxytocin standard. Leydig cells (150,000) stimulated with 0, 25, 50, 100 and 200 uM ascorbate produced and secreted 52, 97, 93, 46 and 46 pmol of an oxytocin-like peptide, respectively. These results support the thesis that Leydig cells are responsible for the production of an oxytocin-like peptide in vitro. Comparison of the individual amino acid content and sequence of this oxytocin-like peptide with authentic oxytocin would confirm unequivocally that Leydig cells are the biosynthetic machinery involved in testicular oxytocin production. (Supported in part by NIH HL 42009)

This Report Abstract may be cited as follows:
Kukucka, Mark A. and Hara P. Misra. 1991. HPLC identification of an oxytocin-like peptide from isolated guinea pig Leydig cells. In: Third Research Day Proceedings, Virginia-Maryland Regional College of Veterinary Medicine, p. 18. Blacksburg, VA.

Submission Details: Report Abstract submitted by Mark A. Kukucka from United States on 04-Sep-2011 17:34.
Abstract has been viewed 2728 times (since 7 Mar 2010).

Mark A. Kukucka Contact Details: Email: dvmphd@gmail.com