| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Dairy and Poultry Sciences, University of Florida, Gainesville 32611
The purpose of this study was to evaluate whether the plasminogen and plasmin system within bovine mammary secretions was influenced by an estrogen treatment that was used to accelerate mammary tissue involution. Holstein cows were injected with 4 ml of ethanol excipient (n = 21) or 15 mg of estradiol-17ß (n = 23) on each of the 4 d that preceded final milk removal. Dates of final milk removal (d 0) were designated as 60 d prior to expected dates of calving. Each mammary quarter was sampled once to collect secretions that corresponded to d 0, 3, 11, and 25 or d 1, 7, 18, and 30 of the dry period. Concentrations of plasminogen, plasmin, and somatic cells in secretions increased earlier for treated cows than for control cows. The ratio of plasminogen to plasmin in secretions decreased earlier for treated cows than for control cows. These responses support the suggestion that the plasminogen and plasmin system is involved in the involution of bovine mammary tissue. Estrogen treatment increased the activation of plasminogen, which was evidenced by a precipitous decrease in the ratio of plasminogen to plasmin that occurred as concentrations of plasminogen and plasmin increased. The activation of plasminogen likely contributed to the increased rate of mammary tissue involution that was effected by exogenous estrogen. Endogenous estrogen secreted by the developing fetal and placental unit might mediate, in part, the gradual involution that occurs during lactation.
Key Words: estrogen • plasmin • mammary gland • involution
Submitted on July 24, 1996
Accepted on January 24, 1997
This article has been cited by other articles:
|
|
 |
|
  A. A. K. Salama, G. Caja, X. Such, R. Casals, and E. Albanell Effect of Pregnancy and Extended Lactation on Milk Production in Dairy Goats Milked Once Daily J Dairy Sci, November 1, 2005; 88(11): 3894 - 3904. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Leitner, U. Merin, and N. Silanikove Changes in Milk Composition as Affected by Subclinical Mastitis in Goats J Dairy Sci, June 1, 2004; 87(6): 1719 - 1726. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. C. Bachman and M. L. Schairer Invited Review: Bovine Studies on Optimal Lengths of Dry Periods J Dairy Sci, October 1, 2003; 86(10): 3027 - 3037. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Gulay, M. J. Hayen, K. C. Bachman, T. Belloso, M. Liboni, and H. H. Head Milk Production and Feed Intake of Holstein Cows Given Short (30-d) or Normal (60-d) Dry Periods J Dairy Sci, June 1, 2003; 86(6): 2030 - 2038. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Shamay, F. Shapiro, G. Leitner, and N. Silanikove Infusions of Casein Hydrolyzates into the Mammary Gland Disrupt Tight Junction Integrity and Induce Involution in Cows J Dairy Sci, April 1, 2003; 86(4): 1250 - 1258. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. V. Capuco, S. E. Ellis, S. A. Hale, E. Long, R. A. Erdman, X. Zhao, and M. J. Paape Lactation persistency: Insights from mammary cell proliferation studies J Anim Sci, March 1, 2003; 81(suppl_3): 18 - 31. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
