Relationship between numbers of alpha 2- and beta 2-adrenoceptors on blood cells of bulls and milkability of their daughters.
Milk yield and milking time were measured on one occasion for several daughters (n = 6-44) from 16 bulls at morning milkings. Blood from the bulls was collected, and platelets and mononuclear leucocytes were isolated. The alpha 2-adrenoceptors on platelet membranes were identified by binding of [3H]rauwolscine, whereas for the determination of beta 2-adrenoceptors on intact mononuclear leucocytes, [3H]CGP-12177 was used. It was found that mean milk flow rate was highly correlated (P < 0.001) with the alpha 2-adrenoceptor densities on blood platelets. No correlation was found with the beta 2-adrenoceptors on mononuclear leucocytes. It is concluded that estimation of the alpha 2-adrenoceptors on blood platelets from bulls could eventually be used to investigate milking characteristics of cows, and might be useful in the future as a marker in genetic studies.
Roets
E
E
Department of Veterinary Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium.
Burvenich
C
C
Hamann
J
J
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D002417:Cattle / Q000097:blood* / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D005260:Female; D007774:Lactation / Q000502:physiology*; D007963:Leukocytes, Mononuclear; D008297:Male; D011412:Propanolamines / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012984:Software; D014316:Tritium; D015016:Yohimbine / Q000378:metabolism
D011412:Propanolamines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D014316:Tritium; D015016:Yohimbine; C033394:CGP 12177