phosphorus-radioisotopes and glycerophosphoethanolamine

Docosahexaenoic acid (DHA), the longest and most unsaturated fatty acid commonly found in biological membranes, is known to affect various membrane properties. In a variety of cell membranes, DHA is primarily incorporated in phosphatidylethanolamines, where its function remains poorly understood. In order to understand the role of DHA in influencing membrane structure, we utilize (31)P NMR spectroscopy to study the phase behavior of 1-stearoyl-2-docosahexaenoyl-sn-glycerophosphoethanolamine (SDPE) in comparison to 1-palmitoyl-2-oleoyl-sn-glycerophosphoethanolamine (POPE) from 20 to 50 degrees C. Spectra of SDPE phospholipids show the formation of inverted hexagonal phase (H(II)) from 20 to 50 degrees C; in contrast, POPE mutilamellar dispersions exist in a lamellar liquid-crystalline phase (L(alpha)) at the same temperatures. The ability of SDPE to adopt nonbilayer phases at a physiological temperature may indicate its role in imparting negative curvature stress upon the membrane and may affect local molecular organization including the formation of lipid microdomains within biological membranes.

Topics: Docosahexaenoic Acids; Magnetic Resonance Spectroscopy; Membrane Microdomains; Phosphatidylethanolamines; Phosphorus Radioisotopes; Temperature

To assess testicular function in experimental varicocele rats, we used 31P magnetic resonance (MR) spectroscopy and compared MR spectroscopic parameters with flow cytometric DNA analysis. In vivo 31P MR spectroscopy and flow cytometric DNA analysis of testes were performed in 10 sham-operated and 9 induced varicocele rats. Although the testicular phosphomonoester (PM)/ATP ratio did not differ between sham-operated and induced varicocele rats, the phosphodiester (PD)/ATP ratio was significantly reduced and the inorganic phosphate (Pi)/ATP ratio was significantly increased in induced varicocele rats. There was no difference between the right and left sides. DNA flow cytometry showed a decrease in the percentage of haploid cells in induced varicocele rats, regardless of the side. This study indicates that in vivo 31P MR spectroscopy provides valuable information for assessment of testicular function.

Topics: Animals; Cell Nucleus; Diploidy; DNA; Flow Cytometry; Glycerylphosphorylcholine; Haploidy; Magnetic Resonance Spectroscopy; Male; Phosphatidylethanolamines; Phosphorus Radioisotopes; Polyploidy; Radionuclide Imaging; Rats; Rats, Sprague-Dawley; Spermatogenesis; Testis; Varicocele