Oct. 20, 1964
COMhfUKICATIONS TO THE
EFFECTO F STRUCTURAL C H A X G E S Compound
TABLE I 4 O N THE
-
1.I' P O S I T I O X
PHARMACOLOGICAL .iCTIVITIES O F O X Y T O C I N
Depressor (fowl)
Oxytocic (rat1
Oxytocin3 5 0 i f 15 4-Decarboxamido-oxytocin4( 4 - ~ - w a m i n o b u t y r iacid-oxytocin) c 108 f 5 4-~-.~lanine-ox~.tocin~~ 65 f 3 4-Glycine-ox ytocin 5.5 i0 2 4-L-Serine-oxytocin?6 230 f 20 Isotocin2' (4-~-serine-8-~-isoleucine-oxytocin j 320 f 15
On the other hand, 2 - l e u ~ i n e - o x y t o c i nhas ~ ~ extremely low activity and 2 - s e r i n e - o x y t o ~ i nhas ~ ~ practically none. It is therefore not surprising that the 2-glycineoxytocin was practically inactive in the bioassays performed. a'ith regard to the %position, substitution of the isoleucine residue in this position by a 5- or 6-carbon aliphatic amino acid30j33s34 and even by the aromatic amino acid phenylalanine (oxypressin) 3 3 36 gives rise (30) R . A . Boissonpas, S. G u t t m a n n , B. Berde, a n d H . K o n z e t t , E x p w i r z f i o , 17, 377 (1961). (31) K Jo4t. J . Rudinger, a n d F. S o r m , Coilecfion Czech. Chrm. C o m m u n . , 28, 1706 (1963). ( 3 2 ) S G u t t m a n n and R A. Boissonnas, H e l v . Chim. A d a , 43, 200 (1960). (33) R . A . Boissonnas, S. G u t t m a n n , P.-A. J a q u e n o u d , a n d J.-P. Waller, ibid , 39, 1421 (1936). (34) J . Rudinger, J. Honzl, a n d M . Zaoral, Coiieclion Czech. C h e m . Commun., 21, 770 (1956); H. N e s v a d b a , J . Honzl, a n d J . Rudinger, i b i d . , 28, 1691 (1963).
448 1
EDITOR
486 72 3G 2.8 195 150
f5 i2 f6 i0 1 f 30 f 12
Activities, units/mg.----Milk-ejecting (rabbit1
+: 16 225 f 7 240 f 55 1i i 1 255 i 45 300 i 15
Pressor (rat)
3.1 f0 1 -0 1
