The Biological Activity of a New Analogue of Oxytocin in Which the Tyrosyl Group Is Replaced by Phenylalanyl

Abstract

A new synthetic analogue of oxytocin with a phenylalanyl group instead of a tyrosyl group has been investigated. The most prominent biological properties of this peptide were its oxytocic activity on the rat or cat uterus in vivo and on milk-ejection pressure in the rabbit. Another remarkable feature was the striking difference in pressor activity measured in spinal cats and in anaesthetized rats. The presence of the phenylalanyl group in the molecule in the above-mentioned position did not increase the antidiuretic potency in unanaesthetized rats. The authors propose a nomenclature for the peptides related to oxytocin and vasopressin.As chemical and biological work on peptides related to oxytocin and vasopressin progresses, the need for a simple and clear nomenclature in this field becomes increasingly greater. We should therefore like to propose a nomenclature along the lines of that already in use for polypeptides of the hypertensin type (see, for example, Rittel, Iselin, Kappeler, Riniker, and Schwyzer, 1957). The amino-acid groups in the oxytocin molecule would be numbered as follows:

The effect of oxytocin and vasopressin and of phenylalanyl3‐oxytocin on the urinary excretion of water and electrolytes in man

“…These results offer some confirmatory evidence in man of the suggestion by Berde et al (1957) and Konzett & Berde (1959) …”

“…1 c) called 'P-analogue 'by Berde, Doepfner & Konzett (1957), 'oxypressin' by Katsoyannis (1957) and here called phenylalanyl3-oxytocin according to the scheme of numbering the amino acids suggested by Konzett & Berde (1959), is of interest because it can be used to assess the relative importance of the amino acids in the 3-and 8-positions in the action of vasopressin on the kidney. It has been found by Berde et al (1957) to have an antidiuretic activity in the rat comparable to that of vasopressin, whereas substitution of the tyrosyl2 group of oxytocin by phenylalanine results in much 19-2 286 W. B. THOMSON less enhancement of the antidiuretic action (Konzett & Berde, 1959).…”

Isoleucyl⁸-Oxytocin, ein biologisch hochwirksames Polypeptid

“…Dieses Phänomen wurde auch bei der Reinigung anderer Oxy tocin-Analoga beobachtet (Konzett, 1959;Berde, Certetti und Konzett, 1959); es bedeutet, daß die biologische Eigenart eines neuen Peptids dieser Klasse bereits bei der pharmakologischen Prüfung des rohen synthetischen Präparates erkannt werden kann.…”

Effect of Tyrosinase Preparations on Oxytocin, Vasopressin and Bradykinin

“…Both groups of workers found an oxytocic potency, measured on the isolated rat uterus, of 30 u./mg. On the other hand, Konzett & Berde (1959) reported that the milk-ejecting potency of the analogue prepared by Jaquenoud & Boissonnas was 140 u./mg. The corresponding analogue of vasopressin, phenylalanine2-lysine8-vasopressin, prepared by Boissonnas & Guttmann (1960) has a pressor potency equal to about one-fifth of that of the parent compound (Berde et al, 1961).…”