Yoshihiko Baba

Structure of the porcine LH- and FSH-releasing hormone. I. The proposed amino acid sequence

Summary The complete amino acid sequence of porcine LH- and FSH- releasing hormone has been provisionally determined by the use on a micro-scale of the combined Edman-dansyl procedure coupled with the selective tritiation method for C-terminal analysis. These procedures were used directly on the digestion products of LH-RH with chymotrypsin and thermolysin, without separation of the fragments. Additional data were provided by high resolution mass spectral fragmentation of LH-RH. On the basis of these results, we propose the following decapeptide sequence for LH-RH: (pyro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2.

Isolation and properties of the FSH and LH-releasing hormone☆

Abstract LH-releasing hormone (LH-RH) was obtained in apparently a homogeneous state from extracts of pig hypothalami. The LH-RH preparation isolated has FSH-releasing hormone (FSH-RH) activity, which appears to be intrinsic to LH-RH. The amino acid composition of LH-RH/FSH-RH as determined on acid hydrolysates is: His 1, Arg 1, Ser 1, Glu 1, Pro 1, Gly 2, Leu 1 and Tyr 1. The hormone isolated stimulates the release of FSH and LH in vivo and in vitro in doses of a few nanograms. This polypeptide appears to represent the hypothalamic hormone which controls the secretion of both LH and FSH from the pituitary.

Structure of the porcine LH- and FSH-releasing hormone. II. Confirmation of the proposed structure by conventional sequential analyses

Abstract The proposed amino acid sequence of porcine LH- and FSH-releasing hormone (LH-RH/FSH-RH) was reinvestigated by Edman-dansyl degradation after the cleavage of N-terminal pyroglutamyl residue by pyrrolidonecarboxylyl (PCA) peptidase. A C-terminal fragment from chymotrypic digest of LH-RH/FSH-RH was found to be identical to synthetic Gly-Leu-Arg-Pro-Gly-NH 2 . The results indicate that the structure initially proposed is correct. The amino acid sequence of porcine LH-RH/FSH-RH is thus (pyro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH 2 .

Structure of the porcine LH-and FSH-releasing Hormone.: I. The proposed amino acid sequence0110 0

AbstractThe complete amino acid sequence of porcine LH- and FSH-releasing hormone has been provisionally determined by the use on a micro-scale of the combined Edman-dansyl procedure coupled with the selective tritiation method for C-terminal analysis. These procedures were used directly on the digestion products of LH-RH with chymotrypsin and thermolysin, without separation of the fragments. Additional data were provided by high resolution mass spectral fragmentation of LH-RH. On the basis of these results, we propose the following decapeptide sequence for LH-RH: (pyro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2.

Evidence for peptide nature of LH and FSH-releasing hormones

Abstract The effects of several chemical and enzymatic treatments on the biological activity of highly purified porcine luteinizing hormone-releasing hormone (LH-RH) and follicle-stimulating hormone-releasing hormone (FSH-RH) (1) were studied in an attempt to define the chemical nature of these hypothalamic hormones. The results obtained are consistent with the concept that LH-RH/FSH-RH activity is due to small basic polypeptide(s), but a conclusive differentiation between LH-RH and FSH-RH cannot yet be made.

Ovulation Induced by Synthetic Luteinizing Hormone-Releasing Hormone in the Hamster

A synthetic decapeptide, corresponding to the chemical structure of luteinizing hormone-releasing hormone from porcine hypothalami, was tested for the induction of ovulation in golden hamsters that had previously been treated with phenobarbital to prevent spontaneous ovulation. Subcutaneous injection of 0.089 to 0.357 nanomole of this synthetic luteinizing hormone-releasing hormone stimulated release of luteinizing hormone and induced ovulation.

Luteinizing hormone-releasing hormone analogs lacking N-terminal pGlu ring structure

Abstract Six analogs of LH-RH lacking N-terminal pGlu ring structure, Gly 1 -LH-RH, formyl Gly 1 -LH-RH, acetyl Gly 1 -LH-RH, propionyl Gly 1 -LH-RH, palmitoyl Gly 1 -LH-RH and acetyl Ala 1 -LH-RH were synthesized. The Gly 1 analog was inactive, whereas acyl Gly 1 analogs except palmitoyl Gly 1 analog showed small but significant LH-RH activity in spite of the lack of the pyrrolidone ring structure. These findings suggest that the -CO-NHCHCO- group is the minimum necessary part of the pGlu residue to exhibit the biological activity.

Studies on the Enzymatic and Chemical Inactivation of Hypothalamic Follicle-Stimulating Hormone-Releasing Hormone

The effect of chemical and enzymatic treatments on the biological activity of porcine follicle-stimulating hormone-releasing hormone (FSH-RH) was studied. FSH-RH activity was not affected by trypsin, pepsin, neuraminidase, carboxy-peptidase A and aminopeptidase M. However, incubationwith chymotrypsin, subtilisin and papain abolished the FSH-RH activity as did treatment with performic acid, hydrochloric acid (0.9 M, 1 h, 100 °C), diazotized sulfanilic acid and N-bromosuccinimide. Nitrous acid, sodium metaperiodate and ninhydrin did not affect the FSH-RH activity appreciably. These results, together with previous information obtained during purification procedures, indicate that FSH-RH is a small basic polypeptide. Tyrosine, histidine, or tryptophan are probably present in the molecule and may be necessary for the biological activity.

On the tryptophan residue in porcine LH and FSH-releasing hormone.

Abstract The effect of 2-hydroxy-5-nitrobenzyl bromide on the biological activity of a preparation of pure porcine LH and FSH-releasing hormone (LH-RH/FSH-RH) was reinvestigated. Since this treatment as well as performic acid and incubation with anhydrous trifluoroacetic acid, caused a complete inactivation of LH-RH/FSH-RH, tryptophan residue is thought to be essential for the biological activity of this polypeptide.

Further studies on the enzymatic and chemical inactivation of hypothalamic FSH-RH.

The effect of chemical and enzymatic treatments on the biological activity of porcine follicle-stimulating hormone-releasing hormone (FSH-RH) was studied. FSH-RH activity was not affected by trypsin, pepsin, neuraminidase, carboxypeptidase A, aminopeptidase M and leucine aminopeptidase. However, incubation with chymotrypsin, subtilisin, papain and pyrrolidone carboxylyl peptidase abolished the FSH-RH activity as did treatment with hydrochloric acid (0.9 m, 1 h, 100 °C), diazotized sulfanilic acid, and N-bromosuccinimide. Nitrous acid, sodium metaperiodate, and ninhydrin did not affect the FSH-RH activity appreciably. Amino acid analyses of the purest FSH-RH preparation showed the following composition: His 1, Arg 1, Ser 1, Glu 1, Pro 1, Gly 2, Leu 1, Trp 1, and Tyr 1. These results and information obtained during purification procedures indicate that a basic polypeptide composed of ten amino acids possesses both LH-RH and FSH-RH activity.