HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bowen, J. M. Articles by Keyes, P. L. Search for Related Content PubMed PubMed Citation Articles by Bowen, J. M. Articles by Keyes, P. L. Agricola Articles by Bowen, J. M. Articles by Keyes, P. L.

Repeated Exposure to Prolactin Is Required to Induce Luteal Regression in the Hypophysectomized Rat¹

^a Department of Physiology and Reproductive Sciences Program, University of Michigan, Ann Arbor, Michigan 48109-0622

We investigated whether prolactin (PRL) treatments resembling the intermittent PRL surges of estrous cycles could induce luteal regression in hypophysectomized rats. Immature female rats were stimulated to ovulate and form corpora lutea with exogenous gonadotropins, and were hypophysectomized following ovulation. A single s.c. injection of either vehicle (VEH) or PRL was administered to each rat on post-hypophysectomy Day 8 and again on Day 11. The four resulting treatment groups consisted of rats that received two injections of VEH, VEH followed by PRL, PRL followed by VEH, or two injections of PRL. Rats were killed 24 or 72 h following the second injection. Plasma 20-dihydroprogesterone, luteal weight, and total luteal protein were determined. One ovary was sectioned for immunohistochemistry for monocytes/macrophages, apoptotic nuclei, and major histocompatibility class II (MHC II) molecules. No effect of time (following injection) was observed on any endpoint, indicating that PRL does not have an ongoing regressive action. Time groups from within each treatment group were therefore pooled for analysis. Significant declines (P < 0.05) in plasma concentrations of 20-dihydroprogesterone, luteal weight, and protein per corpus luteum occurred only after two injections of PRL. Numbers of luteal monocytes/macrophages, apoptotic nuclei, and MHC II-positive cells were low in all groups; numbers of luteal monocytes/macrophages increased following two injections of PRL (P < 0.05). We conclude that PRL has a cumulative regressive effect on the corpus luteum of the hypophysectomized rat. Drawing a parallel with the estrous cycle, we suggest that continued exposure to PRL, over several cycles, is necessary to induce full luteal regression.

First decision: 20 October 1999.

¹ This work was supported by grant HD-33478 from the National Institutes of Health (NIH). Support was also provided by the Morphology Core Facility and the Assays and Reagents Core Facility of the P30 Centre for the Study of Reproduction (through NIH HD-18258).

² Correspondence and current address: J.M. Bowen, Department of Pharmacology and Clinical Pharmacology, University of Auckland, Private Bag 92019, 85 Park Road, Grafton, Auckland, New Zealand. FAX: 64 9 373 7556; j.bowen{at}auckland.ac.nz

This article has been cited by other articles:

				M. J Cannon, J. S Davis, and J. L Pate The class II major histocompatibility complex molecule BoLA-DR is expressed by endothelial cells of the bovine corpus luteum Reproduction, May 1, 2007; 133(5): 991 - 1003. [Abstract] [Full Text] [PDF]

				M. C Peluffo, L. Bussmann, R. L Stouffer, and M. Tesone Expression of caspase-2, -3, -8 and -9 proteins and enzyme activity in the corpus luteum of the rat at different stages during the natural estrous cycle. Reproduction, September 1, 2006; 132(3): 465 - 475. [Abstract] [Full Text] [PDF]

				A. A Goyeneche, J. M Harmon, and C. M Telleria Cell death induced by serum deprivation in luteal cells involves the intrinsic pathway of apoptosis Reproduction, January 1, 2006; 131(1): 103 - 111. [Abstract] [Full Text] [PDF]

				R. Wu, K. H. Van der Hoek, N. K. Ryan, R. J. Norman, and R. L. Robker Macrophage contributions to ovarian function Hum. Reprod. Update, March 1, 2004; 10(2): 119 - 133. [Abstract] [Full Text] [PDF]

				S. Takiguchi, N. Sugino, K. Esato, A. Karube-Harada, A. Sakata, Y. Nakamura, H. Ishikawa, and H. Kato Differential Regulation of Apoptosis in the Corpus Luteum of Pregnancy and Newly Formed Corpus Luteum after Parturition in Rats Biol Reprod, February 1, 2004; 70(2): 313 - 318. [Abstract] [Full Text] [PDF]

				A. A. Goyeneche, I. L. Martinez, R. P. Deis, G. Gibori, and C. M. Telleria In Vivo Hormonal Environment Leads to Differential Susceptibility of the Corpus Luteum to Apoptosis In Vitro Biol Reprod, June 1, 2003; 68(6): 2322 - 2330. [Abstract] [Full Text] [PDF]

				A. A. Goyeneche, R. P. Deis, G. Gibori, and C. M. Telleria Progesterone Promotes Survival of the Rat Corpus Luteum in the Absence of Cognate Receptors Biol Reprod, January 1, 2003; 68(1): 151 - 158. [Abstract] [Full Text] [PDF]

				K. S. Simpson, C. M. Komar, and T. E. Curry Jr Localization and Expression of Tissue Inhibitor of Metalloproteinase-4 in the Immature Gonadotropin-Stimulated and Adult Rat Ovary Biol Reprod, January 1, 2003; 68(1): 214 - 221. [Abstract] [Full Text] [PDF]

				Y.-P. Sun, T. J. Lee, and G. V. Shah Calcitonin Expression in Rat Anterior Pituitary Gland Is Regulated by Ovarian Steroid Hormones Endocrinology, October 1, 2002; 143(10): 4056 - 4064. [Abstract] [Full Text] [PDF]

				F. Gaytan, C. Bellido, C. Morales, and J.E. Sanchez-Criado Luteolytic Effect of Prolactin Is Dependent on the Degree of Differentiation of Luteal Cells in the Rat Biol Reprod, August 1, 2001; 65(2): 433 - 441. [Abstract] [Full Text] [PDF]