Mode of entry of glycosaminoglycan sulfate during epididymal maturation of bull spermatozoa. I. Charge neutralization mechanism.
Heparin uptake by bull spermatozoa from each one of main epididymis regions was investigated to determine whether the heparin binding was modified during epididymal maturation, the heparin internalization differed during the maturation process, and the charge neutralization by histone or polylysine enhances heparin internalization. From our results we conclude that membrane binding of heparin is greater in the spermatozoa from the caput epididymis than in those of the cauda epididymis region (9.41 +/- 2.27 vs. 2.89 +/- 0.72 pmole of [3H]heparin) and that membrane binding of heparin occurs also at 4 degrees C (4.97 +/- 1.36 vs. 1.05 +/- 0.54 pmole of [3H]heparin). It was also clearly shown that heparin uptake requires active metabolism of the cell and that internalization decreases according to the progress of the epididymal maturation process [6.34 +/- 1.25 (caput) vs. 1.74 +/- 0.72 (cauda)]. Finally, charge neutralization of heparin by histone or polylysine did not enhance heparin internalization.
D000818:Animals; D001665:Binding Sites; D001692:Biological Transport; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects; D004594:Electrophysiology; D004822:Epididymis / Q000254:growth & development* / Q000378:metabolism; D006493:Heparin / Q000378:metabolism*; D006657:Histones / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D011107:Polylysine / Q000494:pharmacology; D013094:Spermatozoa / Q000378:metabolism*
D006657:Histones; D011107:Polylysine; D006493:Heparin