Synthesis and biological activity of some analogs of the gonadotropin releasing hormone

Facilitation of Sexual Receptivity in the Female Rat by a Fragment of the LHRH Decapeptide, Ac-LHRH^5-10

“…The behaviorally active fragment has been shown to be inactive in terms of pituitary LH release in vitro and in vivo. This finding supports previous conclusions by others of a dissociation between pituitary and reproductive effects of various LHRH analgos [1,5] and demonstrates that frag ments of LHRH also display a similar dissociation. The present results support the concept of functional differenti ation of elements contained in the LHRH structure.…”

“…Compared to LHRH, des-Gly10 was weakly agonistic and LHRH1' 6 NH2 was weakly antagonistic. These results are in accord with the in vitro effects of the fragments [1,7,8].…”

“…The fragments used in the present study have been shown to be relatively inactive in terms of in vitro LH release [ 1,7,8). To ascer tain their in vivo effects, a separate group of 30 ovariectomized rats was injected with 20 pg estradiol benzoate and 72 h later, jugular blood samples were taken under ether anesthesia.…”

Computational Studies on the Mechanisms of Nonenzymatic Intramolecular Cyclization of the Glutamine Residues Located at N-Termini Catalyzed by Inorganic Phosphate Species

“…Thus, the formation of pGlu residues interferes with the determination of the primary structure of peptides and proteins by Edman degradation. 2,6,12−14 pGlu residues play important roles in the unique biological functions of several regulatory peptides, such as gonadotropinreleasing hormone, 15 thyrotropin-releasing hormone (TRH), 16−18 luteinizing hormone-releasing hormone, 19 and the human monocyte chemotactic protein. 20,21 In particular, the replacement of pGlu residues with other chemical species at the N-termini of TRHs has been reported to decrease significantly both the hormonal potency and receptor-binding ability of TRH.…”

“…pGlu residues play important roles in the unique biological functions of several regulatory peptides, such as gonadotropin-releasing hormone, thyrotropin-releasing hormone (TRH), − luteinizing hormone-releasing hormone, and the human monocyte chemotactic protein. , In particular, the replacement of pGlu residues with other chemical species at the N-termini of TRHs has been reported to decrease significantly both the hormonal potency and receptor-binding ability of TRH . Zhang and Henzel applied Edman analysis to a set of 270 secreted recombinant human proteins and demonstrated that Gln is located at the N-terminal with a frequency of 10.7% .…”