This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted 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 Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bond, C. P. Articles by Summers, R. J. Search for Related Content PubMed PubMed Citation Articles by Bond, C. P. Articles by Summers, R. J.

Increased Expression of the Relaxin Receptor (LGR7) in Human Endometrium during the Secretory Phase of the Menstrual Cycle

Department of Pharmacology (C.P.B., R.J.S.), Monash University, Clayton, Victoria 3800, Australia; Department of Zoology (L.J.P., H.M.G.) and Howard Florey Institute of Experimental Physiology and Medicine (C.S.S.), University of Melbourne, Victoria 3010, Australia; and Centre for Women’s Health Research (F.L.L., P.A.W.R.), Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria 3168, Australia

Address all correspondence and requests for reprints to: Professor R. J. Summers, P.O. Box 13E, Monash University, Victoria, Australia 3800. E-mail: roger.summers{at}med.monash.edu.au.

Relaxin (RLX) is a structural homolog of insulin that is the ligand for the LGR7 receptor. Although the 6k peptide is produced by the ovaries to cause connective tissue remodeling of the rodent and pig reproductive tracts to facilitate parturition, in human reproduction, the role of RLX is less well understood. Binding of human gene 2 (H2) [³³P]-RLX, expression of RLX peptides and the LGR7 receptor was examined in the human uterus at different stages of the menstrual cycle. A significant increase in RLX receptor binding in endometrium was identified by quantitative autoradiography in the secretory compared with the proliferative phase. H2RLX competed with [³³P]-H2RLX binding with higher affinity than porcine RLX during both the proliferative and secretory phases. Increased LGR7 receptor gene expression during the secretory phase paralleled the changes in [³³P]-H2RLX binding. Human gene 1 RLX transcripts were not detected in the uterus, and H2RLX gene expression was low and not influenced by the stage of the menstrual cycle. The studies show that binding to and gene expression of the LGR7 RLX receptor changes markedly with the phases of the menstrual cycle, suggesting a specific role for the hormone in the physiology of the human uterus.

This work was supported in part by a National Health and Medical Research Council Block Grant to the Howard Florey Institute (Reg Key 983001) and an Australian Research Council (ARC) Linkage Grant to Laura Parry, Roger Summers, and Geoff Tregear (LP0211545). P.A.W.R. is a Principal Research Fellow of the National Health and Medical Research Council of Australia (Fellowship Grant 143805). L.J.P. is an ARC QEII Fellow, and C.S.S. is a recipient of an ARC Postdoctoral (Industry) Fellowship.

Abbreviations: B_max, Maximal binding capacity; C_T, cycle number at which DNA amplification is first detected; E-MP, early-midproliferative; E-MS, early-midsecretory; EP, early proliferative; ES, early secretory; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; H2RLX, recombinant human gene 2 RLX; LP, late proliferative; LS, late secretory; M, menstrual; MP, midproliferative; MS, midsecretory; pK_D, –log[dissociation constant]; pK_i, –log[inhibition constant]; PMSF, phenylmethylsulfonylfluoride; PRLX, porcine RLX; RLX, relaxin; 18S, 18S rRNA; VEGF, vascular endothelial growth factor.

This article has been cited by other articles:

				J. Novak, L. J. Parry, J. E. Matthews, L. J. Kerchner, K. Indovina, K. Hanley-Yanez, K. D. Doty, D. O. Debrah, S. G. Shroff, and K. P. Conrad Evidence for local relaxin ligand-receptor expression and function in arteries FASEB J, November 1, 2006; 20(13): 2352 - 2362. [Abstract] [Full Text] [PDF]

				W. Yan, A. A. Wiley, R. A. D. Bathgate, A.-L. Frankshun, S. Lasano, B. D. Crean, B. G. Steinetz, C. A. Bagnell, and F. F. Bartol Expression of LGR7 and LGR8 by Neonatal Porcine Uterine Tissues and Transmission of Milk-Borne Relaxin into the Neonatal Circulation by Suckling Endocrinology, September 1, 2006; 147(9): 4303 - 4310. [Abstract] [Full Text] [PDF]

				R. A. Bathgate, R. Ivell, B. M. Sanborn, O. D. Sherwood, and R. J. Summers International Union of Pharmacology LVII: Recommendations for the Nomenclature of Receptors for Relaxin Family Peptides. Pharmacol. Rev., March 1, 2006; 58(1): 7 - 31. [Abstract] [Full Text] [PDF]

				L. J. PARRY, J. T. McGUANE, H. M. GEHRING, I. G. T. KOSTIC, and A. L. SIEBEL Mechanisms of Relaxin Action in the Reproductive Tract: Studies in the Relaxin-Deficient (Rlx-/-) Mouse Ann. N.Y. Acad. Sci., May 1, 2005; 1041(1): 91 - 103. [Abstract] [Full Text] [PDF]

				C. P. BOND, L. J. PARRY, C. S. SAMUEL, H. M. GEHRING, F. L. LEDERMAN, P. A. W. ROGERS, and R. J. SUMMERS Increased Expression of the Relaxin Receptor (LGR7) in Human Endometrium during the Secretory Phase of the Menstrual Cycle Ann. N.Y. Acad. Sci., May 1, 2005; 1041(1): 136 - 143. [Abstract] [Full Text] [PDF]

				E. A. Pritts, I. P. Ryan, M. D. Mueller, D. I. Lebovic, J. L. Shifren, C. J. Zaloudek, A. P. Korn, P. D. Darney, and R. N. Taylor Angiogenic Effects of Norplant Contraception on Endometrial Histology and Uterine Bleeding J. Clin. Endocrinol. Metab., April 1, 2005; 90(4): 2142 - 2147. [Abstract] [Full Text] [PDF]