The growth rate of an animal is stimulated by administering to the animal a growth promoting amount of a compound of the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5, which can be the same or different, are each selected from the group consisting of hydrogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms and halogen; X is selected from carbonyl and a ketal group of the formula ##STR2## wherein R.sub.6 and R.sub.7, which can be the same or different, are each selected from hydrogen and alkyl having 1 to 3 carbon atoms; A is a linear or branched alkylene having from 1 to 8 carbon atoms; and R.sub.8 and R.sub.9, which can be the same or different, are each selected from the group consisting of hydrogen, alkyl having 1 to 4 carbon atoms, or 2-hydroxy-alkyl wherein the alkyl group has 2 to 4 carbon atoms, or R.sub.8 and R.sub.9, together with the nitrogen atom, form a heterocyclic ring optionally including other heteroatoms; provided that, when X is a ketal group and A is ethylene, the radical ##STR3## is a group other than morpholino.
动物的生长速率通过向动物施用化合物的生长促进量来刺激,该化合物的公式为##STR1##其中R.sub.1、R.sub.2、R.sub.3、R.sub.4和R.sub.5,可以相同也可以不同,分别选自氢、具有1至4个碳原子的烷基、具有1至4个碳原子的烷氧基和卤素的群; X选自酰基和具有公式##STR2##的
缩醛基,其中R.sub.6和R.sub.7,可以相同也可以不同,分别选自氢和具有1至3个碳原子的烷基; A是具有1至8个碳原子的线性或支链烷基; R.sub.8和R.sub.9,可以相同也可以不同,分别选自氢、具有1至4个碳原子的烷基,或2-羟基-烷基,其中烷基具有2至4个碳原子,或R.sub.8和R.sub.9,与氮原子一起,形成一个可能包括其他杂原子的杂环环; 前提是,当X是
缩醛基且A是
乙烯时,基团##STR3##是除
吗啡啉外的其他群。