HOME HELP CONTACT US 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 VAN DER SCHOOT, P. Articles by DE GREEF, W. J. Search for Related Content PubMed PubMed Citation Articles by VAN DER SCHOOT, P. Articles by DE GREEF, W. J.

Female rats which showed 5-day ovarian cycles spontaneously, but 4-day cycles for periods of variable length after induction of pseudopregnancy, were examined. While the time of onset of the ovulatory LH surge at pro-oestrus was the same in both 4- and 5-day cycles, dioestrous progesterone concentrations were dissimilar. The most prominent feature was a sharp increase during the night of the first day of dioestrus of the 4-day cycles. The results are interpreted as suggesting that dioestrous steroid concentrations rather than pro-oestrous LH concentrations are important in establishing cycle duration.