LHRH, Phe(2)-Pro(3)-Phe(6)-

[D-Phe2,6, Pro3]-LH-RH is a potent luteinizing hormone releasing hormone (LHRH) antagonist[1].

Research Areas >> Endocrinology

Signaling Pathways >> Others >> Others

[D-Phe2,6, Pro3]-LH-RH (0.1 pM-1 mM; 24 h) does not alter GnRH binding capacity in pituitary cells but blocks the increase in sites induced by GnRH[2]. [D-Phe2,6, Pro3]-LH-RH (2.7 μM) causes significant increases in thyrotropin (TSH) secretion in pituitaries[3].

[D-Phe2,6, Pro3]-LH-RH (300 mg/monkey, SC, 50 mg/injection; six injections) inhibits spontaneous preovulatory gonadotropin surges and prevents ovulation in the rhesus monkey[1]. [D-Phe2,6, Pro3]-LH-RH (750 μg, single injection at 12:00 h on the day of proestrus) inhibits ovulation in 100% of treated rats[1]. Animal Model: Adult rhesus monkeys[1] Dosage: 300 mg/monkey Administration: SC, every 8 h at a dose of 50 mg/injection; six injections Result: Showed antagonistic activity: 1) an immediate cessation of the LU and FSH surges; 2) prolonged surges and/or abnormal, discontinuous gonadotropin secretion; 3) LH and FSH peaks of diminished magnitude; 4) the absence of concomitant LH and FSH midcycle peaks; 3) LH and FSH peaks of diminished magnitude; 4) the absence of concomitant LH and FSH midcycle peaks; 5) suppression of serum estradiol concentrations without concurrent reductions in serum gonadotropin values; or 6) a failure to identify corpora lutea at the time of laparoscopic visualization of the ovaries.

[1]. Wilks JW, et al. Effect of [D-Phe2, Pro3, D-Phe6]-luteinizing hormone releasing hormone, an antagonist, on preovulatory gonadotropin secretion in the rhesus monkey. Biol Reprod. 1980 Aug;23(1):1-9.

[2]. Loumaye E, et al. Homologous regulation of gonadotropin-releasing hormone receptors in cultured pituitary cells. Science. 1982 Feb 19;215(4535):983-5.

[3]. Gian, et al. TRH, LHRH and Synthetic [D-Phe2-6, Pro3]-LHRH Stimulate in Vitro Thyrotropin Secretion by Crested Newt Pituitaries. TRENDS IN COMPARATIVE ENDOCRINOLOGY AND NEUROBIOLOGY: FROM MOLECULAR TO INTEGRATIVE BIOLOGY. 1998;839(1):522-523.