Biol Reprod Lalor Postdoctoral Fellowships -- Application Deadline January 15, 2009
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

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 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 reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by BERARDINELLI, J. G.
Right arrow Articles by INSKEEP, E. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by BERARDINELLI, J. G.
Right arrow Articles by INSKEEP, E. K.
Agricola
Right arrow Articles by BERARDINELLI, J. G.
Right arrow Articles by INSKEEP, E. K.

Biology of Reproduction, Vol 22, 233-236, Copyright © 1980 by Society for the Study of Reproduction

Source of Circulating Progesterone in Prepubertal Ewes

J. G. BERARDINELLI 1, R. A. DAILEY 1, R. L. BUTCHER 1, , and E. K. INSKEEP 1

1 Division of Animal and Veterinary Sciences, West Virginia University, Morgantown, West Virginia 26506


In ewe lambs peripheral progesterone increases for a 1-4 day period prior to puberty. The source of this increase was investigated in 15 spring-born ewe lambs. Ewes were checked twice daily with a teaser ram throughout the experiment but no signs of behavioral estrus were observed. Daily samples of jugular plasma were assayed for progesterone on the day of collection. Basal concentrations of progesterone (ng/ml; x ± SEM) averaged 0.3 ± 0.1 for all ewes and increased to 1.1 ± 0.1 during the first rise. The duration of the first rise in 5 ewes was 2.5 ± 0.5 days. Progesterone then decreased to 0.4 ± 0.1 for 4 ± 1 days and rose again to 1.9 ± 0.3 ng/ml.

Six to 8 h after progesterone had been elevated in 2 consecutive daily samples during the first (5 ewes) and second (5 ewes) rises, ewes were laparotomized, bilateral ovarian venous samples were drawn and ovariectomy was performed. Five ewes that had not exhibited any rise in progesterone were sampled and ovariectomized at the same time as ewes ovariectomized during the first rise. Concentrations of progesterone were higher (150 ± 18 ng/ml) in venous plasma from ovaries containing luteal tissue than from ovaries that did not contain luteal tissue (1 ± 0.8 ng/ml; P<0.05). Luteal tissue was observed grossly and microscopically in ovaries removed during a rise in progesterone. No ovulation papillae (stigmata) were apparent on luteal structures (7.0 ± 1.7 mm in diameter) in ovaries removed during the first rise in progesterone and no corpora albicantia were observed. Definitive stigmata were observed on corpora lutea (8.2 ± 1.5 mm in diameter) in ovaries removed during the second rise in progesterone and corpora albicantia were present.

After ovariectomy, progesterone decreased to basal concentrations in ewes that had shown either the first or second rise in progesterone, but remained unchanged in those ewes that had not shown a rise. Neither rise in progesterone was preceded by behavioral estrus.

It is concluded that the increase in circulating progesterone prior to puberty in ewe lambs is produced by luteal tissue in the ovary.

Note:
ACKNOWLEDGMENTS Published with the approval of the Director of the West Virginia Agricultural and Forestry Experiment Station as Scientific Paper No. 1600 from the Division of Animal and Veterinary Sciences. Supported by Hatch Project 224 (NE-72). The authors gratefully acknowledge the assistance of Joseph Ottobre in the surgery and collection of blood samples.

Submitted on August 16, 1979
Accepted on October 18, 1979




This article has been cited by other articles:


Home page
 J ANIM SCIHome page
K. R. Kieborz-Loos, H. A. Garverick, D. H. Keisler, S. A. Hamilton, B. E. Salfen, R. S. Youngquist, and M. F Smith
Oxytocin-induced secretion of prostaglandin F2{alpha} in postpartum beef cows: Effects of progesterone and estradiol-17{beta} treatment
J Anim Sci, July 1, 2003; 81(7): 1830 - 1836.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1980 by the Society for the Study of Reproduction.