help button home button Endocrine Society Endocrinology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Goff, J. P.
Right arrow Articles by Hollis, B. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Goff, J. P.
Right arrow Articles by Hollis, B. W.

Endocrinology, Vol 129, 2815-2819, Copyright © 1991 by Endocrine Society

ARTICLES

Parathyroid hormone-related peptide content of bovine milk and calf blood assessed by radioimmunoassay and bioassay

JP Goff, TA Reinhardt, S Lee and BW Hollis
U.S. Department of Agriculture, National Animal Disease Center, Ames, Iowa 50010.

PTH-related peptide (PTH-rP) has recently been discovered to exist in high concentrations in milk. The development of a commercial RIA for PTH-rP has allowed us to extend these studies. We measured the PTH-rP content of milk from 42 Jersey cows from a single farm in various stages of lactation. Colostrum (first milk) contained 56 +/- 12 ng/ml immunoreactive PTH-rP (iPTH-rP). The iPTH-rP contents of milk 1, 2, 3, 5, 7, and 9 months into lactation were 77 +/- 19, 59 +/- 14, 57 +/- 10, 106 +/- 11, 119 +/- 16, and 168 +/- 17 ng/ml, respectively. Plasma was obtained from 7 Jersey calves at birth and at intervals after the ingestion of colostrum. No iPTH-rP was detected in the plasma at birth. Two hours after the ingestion of colostrum, the iPTH-rP content of plasma was 81 +/- 25 pg/ml. The plasma iPTH-rP concentration continued to increase to 384 +/- 84 pg/ml at 7 h and peaked at 444 +/- 84 pg/ml 12 h after birth. Two calves were sampled through the 60th hour after birth, at which time plasma iPTH-rP was 483 +/- 36 pg/ml. The biological activity of the PTH-rP in milk and plasma was assessed by its ability to stimulate cAMP accumulation in ROS 17/2.8 cells. The specificity of this response was determined by the ability of antiserum to PTH-rP to block the activity. The biological activity of the milk samples was between 31-95% of the activity suggested by immunoassay. Biologically active PTH-rP could not be detected in any of the calf plasma samples. These results confirm the presence of biologically active PTH-rP in milk and suggest that the iPTH-rP is capable of being absorbed. However, our results indicate that the biological activity of the PTH-rP is nearly completely absent once in the systemic circulation.




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals
Copyright © 1991 by The Endocrine Society