Expression of functional human chorionic gonadotropin/human luteinizing hormone receptor gene in human uterine arteries.

Abstract

The present study investigated 1) whether extra- and intramyometrial arteries contain hCG/human LH receptor messenger ribonucleic acid (mRNA) and receptor protein, 2) whether hCG can bind to its vascular receptors and regulate the formation of vasoactive eicosanoids, and 3) whether hCG administration for ovulation induction can affect the vascular resistance in uterine arteries. The uterine arteries contain multiple hCG/LH receptor mRNA transcripts in endothelial and smooth muscle cells. The uterine arteries also contain an 80-kilodalton immunoreactive receptor protein in endothelial and smooth muscle cells. The extra- and intramyometrial arteries and an 80-kilodalton receptor protein bind [125I]hCG, which is inhibited by excess unlabeled hCG. The receptor mRNA, receptor protein, and ligand binding are higher in smaller intramyometrial arteries than in larger extramyometrial arteries. Incubation of uterine arteries with highly purified hCG resulted in a dose-dependent increase in immunoreactive cyclooxygenase-1, cyclooxygenase-2, prostacyclin synthase, and 6-keto-prostaglandin-F1 alpha and a decrease in prostaglandin-E2, thromboxane-A2 synthase, and thromboxane-B2. There was a significant decrease in the resistance index in uterine arteries, but not in common carotid arteries, by 16 h after the administration of 10,000 IU hCG for ovulation induction in women. This decrease is positively correlated with serum hCG levels, but not with progesterone or estradiol levels. In summary, these data, demonstrating the expression of functional hCG/LH receptors in human uterine arteries, are novel and may have important implications for physiological uterine blood flow regulation, reproductive failure, and obstetrical hemorrhage.

Human Chorionic Gonadotropin Expression in Human Trophoblasts from Early Placenta: Comparative Study Between Villous and Extravillous Trophoblastic Cells

“…LH/CG receptors have been described in EVCT (35) and in vascular endothelial cells (36). Our study strongly suggests that hCG secreted by invasive EVCT might act as autocrine and/or paracrine factor for EVCT differentiation and/or endothelial cells from the uterine arteries.…”

Luteinising hormone attenuates the vascular response to norepinephrine

“…Studies on various vascular preparations demonstrated that the incubation of arteries with hCG resulted in an increase in types 1 and 2 cyclooxygenase (COX-1, COX-2) and prostacycline (PGI2) synthase, accompanied by a decrease in prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) synthase (Toth et al, 1994). Our results provide experimental evidence for the first time that locally applied LH attenuates the response to norepinephrine in isolated third-order branches of the uterine artery in cycling gilts.…”

“…Functional LH/hCG receptors have been detected in blood vessels of the female genital tract (Lei et al, 1992;Toth et al, 1994;Zięcik et al, 1995), in the umbilical cord (Rao et al, 1996;Wąsowicz et al, 1999), in the mesenteric arteries (Hermsteiner et al, 1999) and in the cavernous sinus-carotid rete vascular complex (Skipor et al, 1999). In pigs, LH/hCG receptors were found in both the uterine and ovarian arteries and veins (Zięcik et al, 1995), while in cows only in the uterine veins but not in the uterine arteries (Shemesh et al, 1997).…”

The gonadotropins: Tissue-specific angiogenic factors?

“…Previous studies, using in situ hybridisation and immunohistochemistry, revealed that the hCG/LHR were abundantly expressed on uterine endothelial cells in vivo (Lei et al, 1992;Toth et al, 1994), and the receptor expression was increased in the luteal phase.…”