| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Division of Endocrinology, Department of Internal Medicine, School of Medicine, University of California Davis, Davis, California 95616, USA
(Requests for offprints should be addressed to J L Turgeon; Email: jlturgeon{at}ucdavis.edu)
Manipulation of endogenous progesterone receptor (PR) does not produce equivalent physiological effects in mouse and rat pituitary cells. To test whether this may be due in part to difference in PR isoform expression, we examined hormonally regulated pituitary PR-A and PR-B mRNA levels using quantitative real-time PCR. The LßT2 mouse gonadotrope line or pituitary cells from adult, ovariectomized rats or mice were cultured with or without 0.2 nM 17ß-estradiol (E2) for 3 days. PR-A was the predominant form expressed for all groups. For mouse cells, E2 led to an increase in both isoforms without a change in the A:B ratio; for rat cells, the PR-B response to E2 was more robust resulting in a decrease in the A:B ratio. Exposure of E2-treated pituitary cells to 200 nM progesterone for 6 h decreased both PR-A and PR-B levels in rat cells, but had no effect on PR isoform expression in mouse cells even when exposure was extended to 12 h. The low level of PR expression found in LßT2 gonadotropes was unaffected by E2, alone or with progesterone. The weak PR expression and lack of responsiveness of LßT2 cells cannot be explained by a male phenotype as was shown by the more than tenfold higher PR mRNA level in primary cultures of male mouse pituitary cells, which responded to E2 stimulation with a proportional increase in PR isoforms similar to female cells. Functionally, E2-stimulated changes in PR mRNA isoform ratios in rat, mouse or LßT2 cells correlated with the degree of progesterone augmentation of GnRH-stimulated LH secretion in these models. These results are consistent with the hypothesis that robust GnRH priming and progesterone augmentation of LH secretion in the rat compared to these events in the mouse are a consequence, in part, of differences in the E2-modulated ratio of PR isoforms.
This article has been cited by other articles:
|
|
 |
|
  Z. Shen, T. Saloniemi, A. Ronnblad, P. Jarvensivu, P. Pakarinen, and M. Poutanen Sex Steroid-Dependent and -Independent Action of Hydroxysteroid (17{beta}) Dehydrogenase 2: Evidence from Transgenic Female Mice Endocrinology, November 1, 2009; 150(11): 4941 - 4949. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Gordon, R. Aguilar, J. C. Garrido-Gracia, S. Guil-Luna, R. Sanchez-Cespedes, Y. Millan, J. Martin de las Mulas, and J. E. Sanchez-Criado Activation of estrogen receptor-{alpha} induces gonadotroph progesterone receptor expression and action differently in young and middle-aged ovariectomized rats Hum. Reprod., October 1, 2009; 24(10): 2618 - 2628. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B.-S. An, S. L. Poon, W.-K. So, G. L. Hammond, and P. C.K. Leung Rapid Effect of GNRH1 on Follicle-Stimulating Hormone Beta Gene Expression in LbetaT2 Mouse Pituitary Cells Requires the Progesterone Receptor Biol Reprod, August 1, 2009; 81(2): 243 - 249. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. G. Thackray, J. L. Hunnicutt, A. K. Memon, Y. Ghochani, and P. L. Mellon Progesterone Inhibits Basal and Gonadotropin-Releasing Hormone Induction of Luteinizing Hormone {beta}-Subunit Gene Expression Endocrinology, May 1, 2009; 150(5): 2395 - 2403. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Mani Progestin Receptor Subtypes in the Brain: The Known and the Unknown Endocrinology, June 1, 2008; 149(6): 2750 - 2756. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Gordon, J. C Garrido-Gracia, R. Aguilar, C. Bellido, J. A G. Velasco, Y. Millan, M. Tena-Sempere, J. Martin de las Mulas, and J. E Sanchez-Criado The ovary-mediated FSH attenuation of the LH surge in the rat involves a decreased gonadotroph progesterone receptor (PR) action but not PR expression J. Endocrinol., March 1, 2008; 196(3): 583 - 592. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. G. Thackray and P. L. Mellon Synergistic Induction of Follicle-Stimulating Hormone {beta}-Subunit Gene Expression by Gonadal Steroid Hormone Receptors and Smad Proteins Endocrinology, March 1, 2008; 149(3): 1091 - 1102. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Andreu-Vieyra, R. Chen, and M. M. Matzuk Effects of Granulosa Cell-Specific Deletion of Rb in Inha-{alpha} Null Female Mice Endocrinology, August 1, 2007; 148(8): 3837 - 3849. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
