0021-972X/92/7.502-0651$03.00/0 Journal of Clinical Endocrinology and Metabolism Copyright 0 1992 by The Endocrine Society

Vol. 75, No. 2

Printed

in USA

The Expression of Human Chorionic Gonadotropin/ Luteinizing Hormone Receptors in Human Endometrial and Myometrial Blood Vessels* Z. M. LEI,

E. RESHEFt,

AND

Ch. V. RAO

Department of Obstetrics and Gynecology, Louisville, Kentucky 40292

University

of

Louisville

School of Medicine,

ABSTRACT

and higher in vessels of both uterine compartments from the secretory compared to proliferative phase, postmenopause, or pregnancy. The blood vessels in omentum, broad ligament, and parametrium did not immunostain for hCG/hLH receptors. A blood vessel seen traversing through parametrium immunostained for the receptor protein only after it entered the myometrium. The blood vessels in nontarget tissues did not immunostain, whereas those in some target tissues, but not all of them, immunostained for the receptor protein. In summary, the present study demonstrates for the first time that human endometrial and myometrial vascular smooth muscle and endothelium express hCG/hLH receptor mRNA and immunoreactive receptor protein. These findings suggest that hCG/hLH may directly regulate blood flow in human uterus and other target tissues. The reproductive state dependency of uterine vascular receptors suggests that these receptors are probably regulated by other reproductive hormones. (J Clin Endocrinol Metab 76: 651-659,1992)

hCG/human LH (hLH) receptors have recently been found in human endometrial and myometrial cells and uterine vasculature. The present study was undertaken to further corroborate the immunocytochemical evidence for the presence of vascular receptors. Northern blot and in situ hybridization analyses have revealed that human uterus contains a major 4.3-kilobase and a minor 2.6-kilobase hCG/hLH receptor mRNA transcript and that these transcripts are present in part in endometrial and myometrial vascular smooth muscle cells and vascular endothelial cells. Immunoblot and immunocytochemical analyses have revealed that human uterus also contains a single immunoreactive receptor protein, and that this receptor protein in part is present in endometrial and myometrial vascular smooth muscle and vascular endothelium. The expression of receptor mRNA and/or immunoreactive receptor protein was higher in myometrial than in endometrial blood vessels,

H

CG AND human LH (hLH) are similar in structure and function and share a common membrane receptor (1, 2). These receptors are present in female and male gonadal cells, where these hormones regulate steroidogenesis(1, 2). Until recently, it was believed that hCG/LH receptors were only present in gonadal cells. However, it is now known that these receptors are also expressed in human (3) and animal uteri (4-6), human Fallopian tubes (7), human placenta (3, B-lo), fetal membranes, decidua (3, lo), and human gestational trophoblastic neoplasms(11). The evidence for these receptors has been obtained by traditional ligand binding measurements(4-6, 8, 9) or immunocytochemistry (3, 7, 10, 1l), using recently available receptor-specific antibodies. The immunocytochemical study has also revealed the presence of hCG/hLH receptors in human uterine blood vessels(3). This finding has prompted further investigation on human uterine vascular receptors with regard to the presence of hCG/hLH receptor mRNA, tissue specificity, and reproductive phase dependency of receptors. Materials

and Methods

All of the materials for light microscopy sciences, Inc. (Warrington. PA); Vectastain

were purchased from PolyABC kits from Vector Labo-

Received June 17, 1991. Address all correspondence and requests for reprints to: Dr. Ch. V. Rao, Department of Obstetrics and Gynecology, 438 MDR Building, University of Louisville School of Medicine, Louisville, Kentucky 40292. * This work was supported by NIH Grant HD-26173. t Present address: Department of Obstetrics and Gynecology, Section of Reproductive Endocrinology and Infertility, University of Oklahoma School of Medicine, P.O. Box 26901, Oklahoma City, Oklahoma 73190.

ratories, Inc. (Burlingame, CA); [a-32P]CTP from New England Nuclear Corp. (Boston, MA); Riboprobe Gemini System from Promega (Madison, WI); EcoRI, BamHI, and RQI DNase from Fisher Scientific (Pittsburgh, PA); Quick Spin Columns from Boehringer Mannheim Corp. (Indianapolis, IN); proteinase-K, sonicated and denatured salmon sperm DNA, poly(A)+ RNA, tRNA, and rRNA from Sigma Chemical Co. (St. Louis, MO); oligo(dT)-cellulose and 0.24. to 9.5-kilobase (kb) RNA ladder from Gibco BRL (Gaithersburg, MD); Genescreen Plus hybridization transfer membrane from New England Nuclear-DuPont Biotechnology Systems (Boston, MA); and other immunochemicals, reagents, molecular biology grade chemicals, and solvents from regular commercial sources. Polyclonal antibodies to synthetic fragments of rat luteal hCG/LH receptors [anti-PCR II-(l-11) and anti-LHR-(15-38)] were kindly provided by Dr. Patrick Roche from the Mayo Clinic (Rochester, MN). Monoclonal antibody to rat luteal hCG/LH receptors was kindly provided by Dr. Judy Luborsky from the TSI Mason Research Institute (Worcester, MA). Porcine LH/hCG receptor cDNA (nucleotides -11 to 2089) in pBluescript SK(+) (Stratagene, La Jolla, CA) was kindly provided by Dr. Hugues Loosfelt from Hormones et Reproduction, Hospital de Bicetre (Kremlin Bicetre, France). Thirty-three uteri (11 from the proliferative phase, 17 from the luteal phase, and 5 from postmenopause) were obtained from women undergoing hysterectomy for benign indications. The phase of the menstrual cycle was determined from the last menstrual period and/or the patient’s chart. After routine examination by pathologists, the specimens were flash-frozen in liquid nitrogen and then transferred to a -80 C freezer. Segments of omentum (n = 2) and broad ligament (n = 3) were also obtained during the surgery and processed in a similar fashion. Small amounts (

luteinizing hormone receptors in human endometrial and myometrial blood vessels.

hCG/human LH (hLH) receptors have recently been found in human endometrial and myometrial cells and uterine vasculature. The present study was underta...
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