| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Articles |
a Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Tokyo 113, Japan
b Genetic Division, National Cancer Center Research Institute, Tokyo 104, Japan
c Laboratory of Molecular and Cellular Biology, Equine Research Institute, Japan Racing Association, Tochigi 320, Japan
From a subtracted cDNA library of rat luteal tissue, where cDNA fragments in functional luteal tissue were subtracted from those in regressing luteal tissue, a cDNA clone corresponding to 26-cholesterol hydroxylase (P450C26) was obtained. It is known that P450C26 catalyzes the conversion of cholesterol to 26-hydroxycholesterol, which blocks cholesterol utilization in the cell, and that 20
-hydroxysteroid dehydrogenase (20-HSD) catalyzes the conversion of progesterone to an inactive steroid, 20-dihydroprogesterone (20-OHP). Thus, using pseudopregnant rats as a model, physiological cooperation of P450C26 and 20-HSD in the reduction of progesterone release toward the end of the luteal phase was evaluated. Levels of P450C26 and 20-HSD mRNA were examined in corpora lutea from pseudopregnant rats by Northern blot or reverse transcription-polymerase chain reaction or both. P450C26 mRNA was ubiquitously expressed in corpora lutea, and its expression increased toward the end of pseudopregnancy, while 20-HSD was expressed in all corpora lutea on Day 16 (Day 0 = the day of after cervical stimulation) but not detected before Day 10. An inhibitor of 20-HSD, STZ26 (D-homo-16-oxa-4-androstene-3,16-dione), was administered at various doses to rats from Day 12 to 20, effectively suppressing the elevation of 20-OHP in a dose-dependent manner but not the depletion of progesterone completely. The expression of P450C26 mRNA was increased as STZ26 dose increased, which negatively correlated with the progesterone levels. These results strongly suggest that P450C26 cooperated with 20-HSD in the reduction of progesterone release from the rat luteal tissue at the end of the functional luteal phase.
2 Correspondence: Michio Takahashi, Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113, Japan. FAX: 81 3815 4266; amtaka{at}hongo.ecc.u-tokyo.ac.jp
3 Current address: Laboratory of Experimental Animal Science, Kitasato University, School of Veterinary Medicine and Animal Science, 35–1 Higashi-23bancho, Towada, Aomori 034, Japan.
This article has been cited by other articles:
|
|
 |
|
  C. Stocco, C. Telleria, and G. Gibori The Molecular Control of Corpus Luteum Formation, Function, and Regression Endocr. Rev., February 1, 2007; 28(1): 117 - 149. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Tinfo and C. Komar Potential role for peroxisome proliferator-activated receptor {gamma} in regulating luteal lifespan in the rat Reproduction, January 1, 2007; 133(1): 187 - 196. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. M. Komar and T. E. Curry Jr Localization and Expression of Messenger RNAs for the Peroxisome Proliferator-Activated Receptors in Ovarian Tissue from Naturally Cycling and Pseudopregnant Rats Biol Reprod, May 1, 2002; 66(5): 1531 - 1539. [Abstract] [Full Text]
|
|
|
|
|
|
B. D. Murphy Models of Luteinization Biol Reprod, July 1, 2000; 63(1): 2 - 11. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
