JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Journal of Dairy Science Vol. 56 No. 8 1033-1041
© 1973 by American Dairy Science Association ®
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
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 reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Raskin, R. L.
Right arrow Articles by Baldwin, R. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Raskin, R. L.
Right arrow Articles by Baldwin, R. L.

Effects of Chronic Insulin and Cortisol Administration on Lactational Performance and Mammary Metabolism in Rats1,2,

R. L. Raskin3, M. Raskin and R. L. Baldwin

Department of Animal Science, University of California, Davis 95616

ABSTRACT

One unit of insulin was administered once daily subcutaneously to rats between days 5 and 17 of lactation. Insulin affected lactational performance by increasing milk production and decreasing milk fat percentage. Hexokinase isozymes also were investigated, but no changes in the ratio of type II to type I or alterations in the contributions of soluble type II and particulate type II to total type II activity were observed. In vitro tissue slice incubation studies using acetate-1-carbon 14 and uniformly labeled glucose-carbon 14 also indicated decreased fat synthesis. These findings are in contrast to studies with cows indicating that chronic insulin administration induced mammary hyperhpogenesis and, thus, indicate a significant species difference in insulin action. Mammary tissue deoxyribonucleic acid and protein were increased in insulin injected as compared to control animals. Simultaneous administration of .5 mg hydrocortisone acetate amplified results suggesting that insulin and Cortisol act in a complementary fashion. Effects of insulin and Cortisol were not attributed to specific enzyme changes but rather to a general increase in synthetic capacity as indicated by greater numbers of mammary cells (deoxyribonucleic acid), cell hypertrophy, increased milk yields, and increased in vitro metabolic activity.

FOOTNOTES

1 Supported in part by USPHS Grant AM07672.

2 Taken from M.S. thesis of R. L. Raskin.

3 Present address: 6607 W. 6th St., Los Angeles, California 90048.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1973 by the American Dairy Science Association ®.