title: Energy metabolism and intracellular pH in boar spermatozoa.
abstract: The effect of energy metabolism on intracellular pH was studied in boar spermatozoa using nuclear magnetic resonance (NMR) spectroscopy and confocal microscopy with the pH-sensitive dye seminaphthorhodafluor (SNARF-1). Freshly ejaculated spermatozoa had a high adenylate energy charge (AEC=0.8), which decreased to 0.6 under aerobic conditions and to 0.2 under anaerobic conditions. Correspondingly, no ATP resonances but high AMP resonance were visible in (31)P-NMR-spectra of the spermatozoa. When an artificial oxygen buffer (Fluosol) and a purpose-built air supply system were used during (31)P-NMR data acquisition, ATP resonances reappeared whereas the AMP resonance disappeared. Boar spermatozoa kept under aerobic conditions have intracellular compartments that differ markedly in pH, as demonstrated by both (31)P-NMR spectroscopy and confocal microscopy. Using confocal microscopy, the midpiece of the flagellum in which all mitochondria are located was identified as an acidic compartment (pH(i-mp) 6.7). The intracellular pH of both the head (pH(i-h)) and the long principal piece of the flagellum (pH(i-pp)) were 7.2 and, thus, only slightly below the extracellular pH (pH(e) 7.3). Storage of spermatozoa in a glucose-free medium at 15 degrees C when they are immotile slowly shifted the pH(i-mp) from 6.7 to 6.9 within 20 h, whereas pH(i-h) and pH(i-pp) remained unchanged (pH 7.1-7.2). When glucose was present in the medium, all visible compartments of the spermatozoa as well as the medium were acidified to pH 6.2 within 20 h. Under these conditions a resonance at 4.8 mg kg(-1) appeared representing glycerol 3-phosphate.
authors.affiliation: Institut für Zoologie, Johannes Gutenberg-Universität, Becherweg 9-11, D-55099 Mainz, Germany. kamp@maol.uni-mainz.de
authors.forename: G
authors.initials: G
authors.lastname: Kamp
authors.forename: G
authors.initials: G
authors.lastname: Büsselmann
authors.forename: N
authors.initials: N
authors.lastname: Jones
authors.forename: B
authors.initials: B
authors.lastname: Wiesner
authors.forename: J
authors.initials: J
authors.lastname: Lauterwein
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003470:Culture Media; D004734:Energy Metabolism; D005947:Glucose; D006863:Hydrogen-Ion Concentration; D007294:Inositol; D007424:Intracellular Fluid / Q000502:physiology*; D019344:Lactic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018613:Microscopy, Confocal; D010100:Oxygen / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism* / Q000648:ultrastructure; D013552:Swine / Q000378:metabolism*
chemical_list: D003470:Culture Media; D019344:Lactic Acid; D000249:Adenosine Monophosphate; D007294:Inositol; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005947:Glucose; D010100:Oxygen