Impact of blood serum insulin-like growth factor I on platelet-activating factor in bull spermatozoa.
The objective of this study was to examine differences in platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine; PAF] in spermatozoa between two lines of Angus beef cattle divergently selected for blood serum insulin-like growth factor I (IGF-I) concentration. Endogenous lipids were extracted from the spermatozoa and endogenous PAF content was determined by radioimmunoassay. The amount of PAF detected in spermatozoa obtained from high IGF-I bulls (n = 8) ranged from 0.145 to 3.571 pM/10(6) cells. The level of PAF extracted from spermatozoa obtained from low IGF-I- bulls (n = 5) ranged from 0.001 to 1.024 pM/10(6) cells. Polynomial regression analysis revealed a significant cubic relationship (R(2) = 0.374; F = 6.292; P < 0.05) between spermatozoa PAF content and blood serum IGF-I concentration. Spermatozoa-derived PAF levels (mean +/- SEM) were significantly higher (P < 0.05) in the high IGF-I group (1.90 +/- 0.39 pM/10(6) cells) than in the low IGF-I group (0.59 +/- 0.20 pM/10(6) cells). High IGF-I bulls have a greater than three-fold higher PAF content in their spermatozoa than low IGF-I bulls. The data demonstrate that not only is PAF present in bull spermatozoa but that levels are significantly higher in individuals with high serum IGF-I concentrations.
Roudebush
W E
WE
Reproductive Biology Associates, Atlanta, GA, USA. roudebush@rba-online.com
Purnell
E T
ET
Davis
M E
ME
D000818:Animals; D002417:Cattle / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D010972:Platelet Activating Factor / Q000032:analysis / Q000378:metabolism*; D011863:Radioimmunoassay / Q000662:veterinary; D012044:Regression Analysis; D012641:Selection, Genetic; D013094:Spermatozoa / Q000378:metabolism*
D010972:Platelet Activating Factor; D007334:Insulin-Like Growth Factor I