HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by McCann, J. P. Articles by Reimers, T. J. Search for Related Content PubMed PubMed Citation Articles by McCann, J. P. Articles by Reimers, T. J.

Studies of Calcium-Binding Protein in Cattle¹

Cornell University^,3, Ithaca, NY 14853

² Address all correspondence to this author.

Abstract

We have developed and validated a double-antibody radioimmunoassay for quantifying bovine calcium-binding protein (CaBP). Cross-reactivity between the antiserum and microgram quantities of thyrocalcitonin, calmodulin, gastrin, cholecystokinin, vasoactive intestinal polypeptide, serum albumin and concentrated extract of bovine pituitary gland was insignificant. Slight cross-reactivity (6%) of the antiserum with parathyroid hormone was demonstrated. Assay sensitivity was .25 ng/ml and intraassay and interassay coefficients of variation ranged from 4 to 11% and 10 to 24%, respectively. The CaBP immunoreactivity was not affected by endogenous Ca concentrations. Plasma and serum concentrations of immunoreactive CaBP were similar. The CaBP concentrations were unaffected when coagulated and anticoagulated blood samples were stored at 4 or 22 C for up to 72 h and when serum was stored at –20, 4 or 22 C for 8 d. Serum CaBP concentrations in cattle were not affected by gonadal steroids, but may have been influenced by age. Treatment with 500 mg of vitamin D3, but not 50 mg of dihydrotachysterol, significantly increased serum Ca and CaBP concentrations in Holstein heifers after a lag period of 7 to 10 d. Serum Ca and CaBP concentrations began to increase in serum at approximately the same time and both exhibited parallel responses to treatment with vitamin D₃. Serum Ca concentrations were positively correlated (r = .81) with CaBP concentrations and this relationship was described by the equation, Y=6.85 + 1.01 – .03X². Serum Ca and CaBP concentrations were still elevated in heifers 75 d after initial treatment with vitamin D₃. The radioimmunoassay we describe provides an opportunity to investigate the role of CaBP in Ca homeostasis during growth, pregnancy, lactation, parturient paresis and other physiological and pathological states in cattle.

¹ The authors thank Drs. R. H. Wasserman and C. S. Fullmer for providing boving CaBP and Eastern Artificial Insemination Cooperative, Ithaca, NY, for use of bulls in the biological studies of CaBP.

³ Diagnostic Endocrinology Laboratory, New York State College of Vet. Med.