title: Histone-mediated agglutination of epididymal spermatozoa and the occurrence of histone receptors on the rat sperm surface.
abstract: Exogenous calf thymus whole histones showed a high degree of specificity to cause agglutination of rat epididymal spermatozoa. Histones had markedly greater (approximately 5-fold) agglutination activity than did salmon protamine whereas a variety of proteins, including strongly basic ones such as herring protamine sulphate, ribonuclease, cytochrome C and lysozyme, had no detectable agglutination activity. Histones F-3 and F-2a had the greatest activity for cell agglutination. Polyamines (5 mM), sialic acid (5 mM) and basic or acidic amino acids (10 mM) had no effect on histone (approximately 8 microM)-mediated sperm agglutination. 32P-Labelled histones showed a high specificity for binding to intact spermatozoa. The binding was saturable at a histone concentration of approximately 0.3 mg/ml and nearly completely displaced at saturating concentrations of native histones. Only unlabelled protamines competed to a small extent for binding of 32P-labelled histones to spermatozoa. The data are consistent with the view that histones bind specifically to sperm surface receptor sites before agglutination of cells.
mesh_terms: D000818:Animals; D004822:Epididymis / Q000502:physiology; D006657:Histones / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D011485:Protein Binding; D051381:Rats; D013073:Sperm Agglutination / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*
chemical_list: D006657:Histones