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Identification of Functional High and Low Affinity States of the Prostaglandin F2 Alpha Receptor in the Ovine Corpus Luteumin Vivo and Their Role in Hormone Pulsatility

Overview
Journal Endocrine
Specialty Endocrinology
Date 2010 Dec 15
PMID 21153167
Citations 1
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Abstract

Equivocal evidence has accumulated for the presence of high and low affinity receptors for PGF(2α) in the corpus luteum based on binding affinities of(3)H-PGF(2α) to cell membranes or separated whole cells. Some studies report only high affinity sites, while others report the occurrence of both high and low affinity sites. We have previously demonstrated, using subluteolytic levels of PGF(2α), the existence of functional high affinity luteal PGF(2α) receptors which show desensitization and recovery after 6 to 9 h. The present study, using direct intra-arterial infusions of PGF(2α) into the autotransplanted ovary in conscious sheep, was designed to probe for the existence of functional high and low affinity states of the PGF(2α) receptor in the corpus luteumin vivo. Subluteolytic and luteolytic concentrations of PGF(2α) (100 pg/min and 2500 pg/min, respectively) were infused sequentially, each for 2 h, into the ovary during the luteal phase (n=7 sheep). The same low and high concentrations of the inactive metabolite of PGF(2α) (PGFM) were given over the same time periods as negative controls (n=4 sheep). During the 2 h intra-arterial infusion of 100 pg/min of PGF(2α) the secretion rate of oxytocin increased (P<0.01) while the secretion rate of progesterone was unaffected. In contrast, during the 2 h intra-arterial infusion of 2500 pg/min of PGF(2α), secretion rate of oxytocin increased (P<0.01) and secretion rate of progesterone now began to decline (P<0.05). During the 2 h infusions of identical concent-rations of PGFM, the secretion rate of oxytocin and progesterone remained unchanged. These results indicate the existence of functional high and low affinity states of the PGF(2α) receptor within the ovine corpus luteumin vivo.

Citing Articles

Effects of luteinizing hormone and prostaglandin F(2α) on gap junctional intercellular communication of ovine luteal cells throughout the estrous cycle.

Grazul-Bilska A, Redmer D, Reynolds L Endocrine. 2010; 5(2):225-33.

PMID: 21153115 DOI: 10.1007/BF02738710.

References
1.
Balapure A, Caicedo I, Kawada K, Watt D, Rexroad Jr C, Fitz T . Multiple classes of prostaglandin F2 alpha binding sites in subpopulations of ovine luteal cells. Biol Reprod. 1989; 41(3):385-92. DOI: 10.1095/biolreprod41.3.385. View

2.
Negishi M, Sugimoto Y, Irie A, Narumiya S, Ichikawa A . Two isoforms of prostaglandin E receptor EP3 subtype. Different COOH-terminal domains determine sensitivity to agonist-induced desensitization. J Biol Chem. 1993; 268(13):9517-21. View

3.
Sakamoto K, Ezashi T, Miwa K, Okuda-Ashitaka E, Houtani T, Sugimoto T . Molecular cloning and expression of a cDNA of the bovine prostaglandin F2 alpha receptor. J Biol Chem. 1994; 269(5):3881-6. View

4.
Theodosis D, Wooding F, Sheldrick E, Flint A . Ultrastructural localisation of oxytocin and neurophysin in the ovine corpus luteum. Cell Tissue Res. 1986; 243(1):129-35. DOI: 10.1007/BF00221861. View

5.
Flint A, Sheldrick E . Ovarian secretion of oxytocin is stimulated by prostaglandin. Nature. 1982; 297(5867):587-8. DOI: 10.1038/297587a0. View