Biology of Reproduction, Vol 56, 625-631, Copyright © 1997 by Society for the Study of Reproduction

ARTICLES

Functional oxytocin receptors in bovine granulosa cells

K Okuda, Y Uenoyama, Y Fujita, K Iga, K Sakamoto and T Kimura
Division of Animal Science and Technology, Faculty of Agriculture, Okayama University, Japan. kokuda@cc.okayama-u.ac.jp

The aim of this study was to identify the presence of functional oxytocin (OT) receptors on bovine granulosa cells. Freshly prepared bovine granulosa cells from small (3-5 mm in diameter) or preovulatory (mature) follicles were examined for OT receptors by a radioreceptor assay. Scatchard analysis revealed that both binding capacity and affinity in granulosa cells from small follicles were significantly higher than those in granulosa cells from mature follicles (p < 0.01). With use of a reverse transcriptase polymerase chain reaction analysis, expression of OT receptor mRNA was detected in granulosa cells obtained from both small and mature follicles. When the granulosa cells obtained from small follicles were cultured in Dulbecco's Modified Eagle's Medium and Ham's F-12 medium (1:1 [v:v]) with 10% calf serum up to 72 h, as the period of culture was prolonged, the concentration of OT receptor decreased with increases of progesterone and OT release in the medium. However, the binding affinity was not changed during culture for 72 h. When bovine follicular oocytes with cumulus oophorus were cultured for 24 h in tissue culture Medium-199 with 10% fetal calf serum and OT (0-10 nM), the percentages of oocytes reaching maximum cumulus expansion were significantly increased at 0.5, 1, and 10 nM OT, although nuclear maturation in oocytes surrounded by compact cumulus cells was not affected by the addition of OT. Coexposure with OT antagonist blocked the stimulatory effect of OT on cumulus expansion, confirming the specificity of the effect. Furthermore, anti-OT rabbit serum inhibited the percentages of oocytes with expanded cumulus compared to those supplemented with normal rabbit serum (p <0.05). The overall results indicate the presence of functional OT receptors in bovine granulosa cells and support the hypothesis that OT plays a role (or roles) in regulating the function of granulosa cells as an autocrine factor during follicular growth.

This article has been cited by other articles:

				J. J. Peluso Multiplicity of Progesterone's Actions and Receptors in the Mammalian Ovary Biol Reprod, July 1, 2006; 75(1): 2 - 8. [Abstract] [Full Text] [PDF]

				A. L Siebel, R. A D Bathgate, and L. J Parry Differential expression of mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby Reproduction, May 1, 2005; 129(5): 639 - 649. [Abstract] [Full Text] [PDF]

				J. J. Jaroszewski, D. J. Skarzynski, and W. Hansel Nitric Oxide as a Local Mediator of Prostaglandin F2{alpha}-Induced Regression in Bovine Corpus Luteum: An In Vivo Study Experimental Biology and Medicine, October 1, 2003; 228(9): 1057 - 1062. [Abstract] [Full Text] [PDF]

				K. Okuda, Y. Uenoyama, B. Berisha, I. G. Lange, H. Taniguchi, S. Kobayashi, S.-i. Kobayashi, A. Miyamoto, and D. Schams Estradiol-17{beta} Is Produced in Bovine Corpus Luteum Biol Reprod, December 1, 2001; 65(6): 1634 - 1639. [Abstract] [Full Text] [PDF]

				G. Gimpl and F. Fahrenholz The Oxytocin Receptor System: Structure, Function, and Regulation Physiol Rev, April 1, 2001; 81(2): 629 - 683. [Abstract] [Full Text] [PDF]

				D. J. Skarzynski, S. Kobayashi, and K. Okuda Influence of Nitric Oxide and Noradrenaline on Prostaglandin F2{alpha}-Induced Oxytocin Secretion and Intracellular Calcium Mobilization in Cultured Bovine Luteal Cells Biol Reprod, October 1, 2000; 63(4): 1000 - 1005. [Abstract] [Full Text]

				R. Sakumoto, B. Berisha, N. Kawate, D. Schams, and K. Okuda Tumor Necrosis Factor-{alpha} and Its Receptor in Bovine Corpus Luteum Throughout the Estrous Cycle Biol Reprod, January 1, 2000; 62(1): 192 - 199. [Abstract] [Full Text]

				D. J. Skarzynski and K. Okuda Sensitivity of Bovine Corpora Lutea to Prostaglandin F2{alpha} Is Dependent on Progesterone, Oxytocin, and Prostaglandins Biol Reprod, June 1, 1999; 60(6): 1292 - 1298. [Abstract] [Full Text]