Luteinizing Hormone Releasing Hormone (LHRH)

Luteinizing hormone releasing hormone human acetate salt (LHRH) is a selective acitivator of MMP-2 and MMP-9 [1, 2].

Luteinizing hormone-releasing hormone (LHRH), also known as Gonadotropin-releasing hormone (GnRH) is a trophic peptide hormone which secreted by GnRH neurons and plays an important role in the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary [3].

MMP-2 (matrix metalloproteinase-2) and MMP-9 (matrix metalloproteinase-9) belong to the MMP family that play an important role in the breakdown of extracellular matrix (ECM) in normal physiological processes, for example, embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis [2].

When tested with Ishikawa and ECC-1 cell lines, LHRH resulted in the increase of MMP-9 expression which induced cell invasion and it was also showed that GPR101 mediated the LHRH activity and cooperated to function in the metastatic potential of endometrial cancer cells [1]. In human decidual endometrial stromal cells, LHRH with its receptor induced the activation of MMP-2 and MMP-9 [2].

References:
[1].  Cho-Clark, M., et al., GnRH-(1-5) Activates Matrix Metallopeptidase-9 to release Epidermal Growth Factor and Promote Cellular Invasion. Mol Cell Endocrinol, 2015.
[2].  Wu, H.M., et al., Gonadotropin-releasing hormone type II (GnRH-II) agonist regulates the motility of human decidual endometrial stromal cells: possible effect on embryo implantation and pregnancy. Biol Reprod, 2015. 92(4): p. 98.
[3].  Garnick, M.B. and M. Campion, Abarelix Depot, a GnRH antagonist, v LHRH superagonists in prostate cancer: differential effects on follicle-stimulating hormone. Abarelix Depot study group. Mol Urol, 2000. 4(3): p. 275-7.

GnRH antagonists: a new generation of long acting analogues incorporating p-ureido-phenylalanines at positions 5 and 6.[Pubmed:11462984]

J Med Chem. 2001 Feb 1;44(3):453-67.

A series of antagonists of gonadotropin-releasing hormone (GnRH) of the general formula Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph/4Amf(P)-D4Aph/D4Amf(Q)-Leu-ILys-Pro-DAla-NH2 was synthesized, characterized, and screened for duration of inhibition of luteinizing hormone release in a castrated male rat assay. Selected analogues were tested in a reporter gene assay (IC50 and pA2) and an in vitro histamine release assay. P and Q contain urea/carbamoyl functionalities designed to increase potential intra- and intermolecular hydrogen bonding opportunities for structural stabilization and peptide/receptor interactions, respectively. These substitutions resulted in analogues with increased hydrophilicity and a lesser propensity to form gels in aqueous solution than azaline B [Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(Atz)-D4Aph(Atz)-Leu-ILys-Pro-DAla-NH2 with Atz = 3'-amino-1H-1',2',4'-triazol-5'-yl, 5], and in some cases they resulted in a significant increase in duration of action after subcutaneous (s.c.) administration. Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(L-hydroorotyl)-D4Aph(carbamoyl)-Leu-ILys-Pro-DAla-N H2 (acetate salt is FE200486) (31) and eight other congeners (20, 35, 37, 39, 41, 45-47) were identified that exhibited significantly longer duration of action than acyline [Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(Ac)-D4Aph(Ac)-Leu-ILys-Pro-DAla-NH2] (6) when administered subcutaneously in castrated male rats at a dose of 50 microg in 100 microL of phosphate buffer. No correlation was found between retention times on a C18 reverse phase column using a triethylammonium phosphate buffer at pH 7.0 (a measure of hydrophilicity) or affinity in an in vitro human GnRH report gene assay (pA2) and duration of action. FE200486 was selected for preclinical studies, and some of its properties were compared to those of other clinical candidates. In the intact rat, ganirelix, abarelix, azaline B, and FE200486 inhibited plasma testosterone for 1, 1, 14, and 57 days, respectively, at 2 mg/kg s.c. in 5% mannitol (injection volume = 20 microL). Based on the information that 31, 33, 35 and 37 were significantly shorter acting than acyline or azaline B after intravenous administration (100 microg/rat), we surmised that the very long duration of action of the related FE200486 (for example) was likely due to unique physicochemical properties such as solubility in aqueous milieu, comparatively low propensity to form gels, and ability to diffuse at high concentrations in a manner similar to that described for slow release formulations of peptides. Indeed, in rats injected s.c. with FE200486 (2 mg/kg), plasmatic concentrations of FE200486 remained above 5 ng/mL until day 41, and the time after which they dropped below 3 ng/mL and plasma LH levels started rising until full recovery was reached at day 84 with levels of FE200486 hovering around 1 ng/mL. Additionally, FE200486 was less potent at releasing histamine from isolated rat mast cells than any of the GnRH antagonists presently described in preclinical reports.

Comparison of tolerability and adverse events following treatment with two GnRH agonists in patients with advanced prostate cancer.[Pubmed:24354113]

Urol Nurs. 2013 Sep-Oct;33(5):236-44, 248.

This multicenter, randomized, crossover, open-label study (ClinicalTrials.gov identifier: NCT01161563) assessed patients'and clinicians'perceptions of injection site tolerability and adverse events following the intramuscular injection of triptorelin pamoate or subcutaneous injection of leuprolide acetate in 107 male, patients with advanced prostate cancer.

In vitro effect of gonadotropin-releasing hormone agonist on natural killer cell cytolysis in women with and without endometriosis.[Pubmed:14749633]

Am J Obstet Gynecol. 2004 Jan;190(1):44-9.

OBJECTIVE: The purpose of this study was to assess the in vitro effect of gonadotropin-releasing hormone agonist on natural killer cell activity in women with and without endometriosis and to ascertain whether gonadotropin-releasing hormone agonist effects on natural killer cell activity are direct or mediated solely through the hypoestrogenic state that they produce in vivo. STUDY DESIGN: With use of a chromium 51 release microcytotoxicity assay with K562 target cells, natural killer cell activity was measured after the incubation of mononuclear cells with leuprolide acetate that was obtained from 16 patients with endometriosis and 11 control subjects. RESULTS: The cytotoxicity of natural killer cells that were obtained from patients with endometriosis was reduced significantly (P<.001) with leuprolide. Natural killer cell cytotoxicity from control patients was also significantly decreased (P=.005) with gonadotropin-releasing hormone agonist. Natural killer cell cytotoxicity was significantly lower in patients with endometriosis than in control patients (P=.029). CONCLUSION: These findings suggest a direct immunomodulatory role of gonadotropin-releasing hormone agonist on natural killer cell activity and confirm previous findings that patients with endometriosis have reduced natural killer cell cytotoxicity.

Hydrothermal endometrial ablation can reduce the need for hysterectomy and transfusion.[Pubmed:20932367]

JSLS. 2010 Apr-Jun;14(2):192-5.

Women seeking emergency care for severe uterine hemorrhage with profound anemia often undergo transfusion dilatation curettage and ultimately hysterectomy. The purpose of this article is to describe a modern conservative approach to treating persistent uterine hemorrhage unresponsive to medical therapy, avoiding transfusion and allowing for nonemergent future therapy without the potential complications of transfusion. Six patients with unremitting uterine bleeding were included in the study performed in the Department of Gynecology at an academically affiliated general hospital. Patients underwent successful hydrothermal endometrial ablation after failed medical therapy. This procedure is effective in controlling severe uterine bleeding in patients with large intrauterine fibroids; thus, the number of women being transfused can be significantly reduced.