Immunoreactive gonadotropin-releasing hormone in porcine reproductive tissues.
Studies were aimed to identify and characterize IR-GnRH in the porcine endometrium, ovary, oviduct, and compare that with GnRH of hypothalamic and placental origin. RP-HPLC profiles revealed that all tissue extracts contained three peaks of IR-GnRH. Extraction with radioiodinated 125I-GnRH also resulted in three similar peaks, indicating these two extra peaks as an extraction artifact. Radioreceptor assay showed endometrial and ovarian ultrafiltrates displaced binding of 125I-GnRH analog to pituitary membrane. Secretion of uterine IR-GnRH was increased in ovariectomized, progesterone-treated gilts, as compared to the control. Treatment with estradiol + progesterone in ovariectomized gilts further increase uterine secretion of IR-GnRH. These results demonstrate that IR-GnRH identified in the porcine reproductive tissues possesses hydrophobicity similar to those in hypothalamus and placenta; endometrial IR-GnRH binds to pituitary GnRH receptors; and uterine secretion of IR-GnRH is modulated by ovarian steroids.
Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens 30602.
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D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004717:Endometrium / Q000737:chemistry*; D005187:Fallopian Tubes / Q000737:chemistry*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis* / Q000378:metabolism; D007031:Hypothalamus / Q000737:chemistry; D010053:Ovary / Q000737:chemistry*; D010920:Placenta / Q000737:chemistry; D011247:Pregnancy; D011863:Radioimmunoassay; D011869:Radioligand Assay; D011966:Receptors, LHRH / Q000378:metabolism; D013552:Swine; D014599:Uterus / Q000378:metabolism
D012739:Gonadal Steroid Hormones; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone