R. O. Studer

Ontention of antisera against a hypothalamic decapeptide (luteinizing hormone/follicle stimulating hormone releasing hormone) which stimulates the release of pituitary gonadotropins and development of its radioimmunoassay

Abstract Using the classical approach, a decapeptide was synthesized with the structure of porcine luteinizing hormone/follicle stimulating hormone releasing hormone reported by Matsuo, H., Baba, Y., Nair, R. M. G., Arimura, A. and Schally, A. V. (1971) Biochem. Biophys. Res. Commun. 43, 1393–1399. As already reported, this peptide was capable of inducing in vitro the release of luteinizing hormone and follicle stimulating hormone from rat pituitary glands. A specific antiserum against luteinizing hormone/follicle stimulating hormone releasing hormone has been generated in the guinea pig and this allowed the development of a radioimmunoassay for this peptide. The antisera, at a final dilution of 1 100 to 1 600 depending on the antiserum used, were able to bind 35% of the 131 I-labelled antigen. The sensitivity of this assay method was 50 pg of luteinizing hormone/follicle stimulating hormone releasing hormone. The following substances did not cross-react: oxytocin, lysine-vasopressin, synthetic thyroid stimulating hormone releasing hormone, ovine luteinizing hormone, follicle stimulating hormone and prolactin. Des-Trp 3 luteinizing hormone/follicle stimulating hormone releasing hormone, pyroglutamyl-histidyl-tryptophan and seryl-tyrosyl-glycyl-leucyl-arginyl-prolyl-glycinamide, exhibited flatter curves than luteinizing hormone/follicle stimulating hormone releasing hormone with a cross-reactivity of about 1 1000 . Using this method, luteinizing hormone/follicle stimulating hormone releasing hormone was assayed in extracts of the sheep stalk-median eminence and of the hypothalamus and in jugular vein blood from a normal ram and from normal male rats, from cyclic ewe and from hypophysectomized ram and rats. It was concluded that luteinizing hormone/follicle stimulating hormone releasing hormone is present in hypothalamic extracts and in plasma of sheep and rat.

Synthesen in der Polymyxin-Reihe. 4. Mitteilung. Synthese des cyclischen Decapeptids 8γ

In order to elucidate the structure of natural polymyxin B1 the cyclic decapeptide 8 γ(V, Fig. 3, with 8 amino acids in the ring and the side chain attached in γ-position) has been synthesized. This is one of the four possible structures deduced for the natural product by the usual degradation methods. The cyclic decapeptide 8 γ appears not to be identical with polymyxin B1 in view of its reduced antibacterial activity and different optical rotatory power.

Synthesen in der Depsipeptid-Reihe, 4. Mitt.: Struktur und mikrobiologische Aktivität in der Enniatin-Reihe

Es wird der Einflus der Ringstruktur, der Ringgrose und der Anzahl der N-Methylgruppen auf die mikrobiologische Aktivitat der Enniatine untersucht. Alle diese Faktoren scheinen fur die Aktivitat wichtig zu sein.

Synthesis of [4-leucine]-arginine-vasotocin, a natriuretic analogue of arginine-vasotocin

Es wird die Synthese des 4-Leucin-Analogen des Arginin-vasotocins (=[Leu4, Arg8]-oxytocin) beschrieben.