Abstract: The invention relates to novel gonadoliberin nonapeptide ethylamide or decapeptide amide derivatives of the general formula (I),Glp-His-Trp-Ser-Tyr-X.sub.1 -X.sub.2 -X.sub.3 -Pro-X.sub.4 (I)whereinX.sub.1 stands for a 2-aminobenzoic or 3-aminobenzoic acid group;X.sub.2 stands for a leucyl, tryptophyl or phenylalanyl group;X.sub.3 means an arginyl, leucyl or glutaminyl group; andX.sub.4 represents a glycylamide or ethylamide group, as well as their acid addition salts and pharmaceutical presparations containing these compounds. Further on, the invention relates to a process for preparing these compounds and preparations.The gonadoliberin derivatives of the invention can more effectively be used for reproduction biological purposes as compared to the derivatives known so far.

Abstract: The invention relates to a process for producing sexual products suitable for natural or artificial fertilization from mammalia through controlling the activity of their sexual organs in their pre- and post-natal lives, during their infancy, puberty and mature state and, in a given case, to produce offsprings from them as well as to increase several times the production of sexual products to a level far above that typical of the life's performance of the species. According to the invention the mammalia are treated at least once and at most 60 times with a compound of general formula (I),Glp-His-Trp-Ser-Tyr-X.sub.1 -X.sub.2 -X.sub.3 -Pro-X.sub.4, (I)whereinX.sub.1 means a glycil-group or any other natural or synthetic D-aminoacid group,X.sub.2 means an L-aminoacid-group with a side chain of an alkyl-, phenyl, or triptophyl group containing 1-4 carbon atoms,X.sub.3 means an L-aminoacid group having a side chain of an alkyl group with 1-4 carbon atoms or an alkanoyl-amide group of 2-4 carbon atoms andX.sub.

Abstract: The invention relates to gonadoliberin derivatives of the general formula (I)Glp--His--Trp--Ser--Tyr--X.sub.1 --X.sub.2 --X.sub.3 --Pro--X.sub.4whereinX.sub.1 is a glycyl group or a D-isomer of any natural or synthetic amino acid group,X.sub.2 represents an L-amino acid group having 1 to 4 carbon atoms in the side chain, L-phenyl-alanyl or L-tryptophyl group,X.sub.3 represents an L-amino acid group having a C.sub.1-4 alkyl or C.sub.2-4 alkanoyl-amide side chain, andX.sub.4 is a glycine amide or a C.sub.1-4 alkyl amide group,with the proviso that if X.sub.1 stands for a group other than glycyl and X.sub.2 is a tryptophyl group then X.sub.3 may not be leucyl, and the addition salts formed with therapeutically useable acids and complexes thereof. Furthermore the invention relates to a process for preparing these compounds.The new gonadoliberin derivatives can be effectively used for the reproduction process of fish, birds and mammals.

Abstract: The invention relates to a process for obtaining ready-for-fertilization sexual products from sexually mature fish in a period independent of their natural spawning season, in which actual stage of ripening is determined by probing of sexual products [sperm or eggs], fish not yet ripe for ovulation are separated from ripe fish, compounds of hormonal effect are administered to fish, and after the ovulation sexual products are obtained from the fish or from their environment.In the process according to the invention a nonapeptide-C.sub.1-4 -alkyl-amide or a decapeptide amide of the general formula (I),Glp-His-Trp-Ser-Tyr-X.sub.1 -X.sub.2 -X.sub.3 -Pro-X.sub.4 (I)whereinX.sub.1 is a glycyl group or a D-isomer of any natural or synthetic amino acid group,X.sub.2 represents an L-amino acid group having 1 to 4 carbon atoms in the side chain, L-phenyl-alanyl or L-tryptophyl group,X.sub.3 represents an L-amino acid group having a C.sub.1-4 alkyl or C.sub.2-4 alkyl-amide side chain,X.sub.4 is a glycine-amide or a C.