A pharmaceutical composition comprising suitable pharmaceutical excipients and also comprising a prodrug conjugate of the human growth hormone (hGH) of formula hGH-NH-L a -S 0, wherein hGH-NH represents the hGH residue conjugated with one of its primary amino groups to L a; L a represents a functional group, which is self hydrolysable (auto-cleavable) by an auto-cleavage inducing group G a; and S 0 is of formula wherein S 00 is CH 2; or C; S 0A is an alkylene chain having from 1 to 20 carbon atoms, which is optionally interrupted or terminated by one or more groups, cycles or heteroatoms selected from the group consisting of optionally substituted heterocycle; O; S; C; and NH; BS 1, BS 2, BS 3 are independently selected from the group consisting of N; and CH; S 0B, S 1A are independently an alkylene chain having from 1 to 200 carbon atoms, which is optionally interrupted or terminated by one or more groups, cycles or heteroatoms selected from the group consisting of optionally substituted heterocycle; O; S; C; and NH; S 0C, S 1B, are (C) n2 (CH 2) n1 (OCH 2 CH 2) n OCH 3, wherein each n is independently an integer from 100 to 500, each n1 is independently 0, 1, 2, 3, 4, 5, 6, 7,or 8, and n2 is 0 or 1; S 2, S 3 are independently hydrogen; or (C) n2 (CH 2) n1 (OCH 2 CH 2) n OCH 3, wherein each n is independently an integer from 100 to 500, each n1 is independently 0, 1, 2, 3, 4, 5, 6, 7,or 8, and n2 is 0 or 1, provided that at least one of S 2, S 3 is other than hydrogen; and R 2, R 3 are selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tertiary butyl. hGH-NH represents the hGH residue conjugated with one of its primary amino groups to L a; L a represents a functional group, which is self hydrolysable (auto-cleavable) by an auto-cleavage inducing group G a; and S 0 is of formula wherein S 00 is CH 2; or C; S 0A is an alkylene chain having from 1 to 20 carbon atoms, which is optionally interrupted or terminated by one or more groups, cycles or heteroatoms selected from the group consisting of optionally substituted heterocycle; O; S; C; and NH; BS 1, BS 2, BS 3 are independently selected from the group consisting of N; and CH; S 0B, S 1A are independently an alkylene chain having from 1 to 200 carbon atoms, which is optionally interrupted or terminated by one or more groups, cycles or heteroatoms selected from the group consisting of optionally substituted heterocycle; O; S; C; and NH; S 0C, S 1B, are (C) n2 (CH 2) n1 (OCH 2 CH 2) n OCH 3, wherein each n is independently an integer from 100 to 500, each n1 is independently 0, 1, 2, 3, 4, 5, 6, 7,or 8, and n2 is 0 or 1; S 2, S 3 are independently hydrogen; or (C) n2 (CH 2) n1 (OCH 2 CH 2) n OCH 3, wherein each n is independently an integer from 100 to 500, each n1 is independently 0, 1, 2, 3, 4, 5, 6, 7,or 8, and n2 is 0 or 1, provided that at least one of S 2, S 3 is other than hydrogen; and R 2, R 3 are selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tertiary butyl. S 00 is CH 2; or C; S 0A is an alkylene chain having from 1 to 20 carbon atoms, which is optionally interrupted or terminated by one or more groups, cycles or heteroatoms selected from the group consisting of optionally substituted heterocycle; O; S; C; and NH; BS 1, BS 2, BS 3 are independently selected from the group consisting of N; and CH; S 0B, S 1A are independently an alkylene chain having from 1 to 200 carbon atoms, which is optionally interrupted or terminated by one or more groups, cycles or heteroatoms selected from the group consisting of optionally substituted heterocycle; O; S; C; and NH; S 0C, S 1B, are (C) n2 (CH 2) n1 (OCH 2 CH 2) n OCH 3, wherein each n is independently an integer from 100 to 500, each n1 is independently 0, 1, 2, 3, 4, 5, 6, 7,or 8, and n2 is 0 or 1; S 2, S 3 are independently hydrogen; or (C) n2 (CH 2) n1 (OCH 2 CH 2) n OCH 3, wherein each n is independently an integer from 100 to 500, each n1 is independently 0, 1, 2, 3, 4, 5, 6, 7,or 8, and n2 is 0 or 1, provided that at least one of S 2, S 3 is other than hydrogen; and R 2, R 3 are selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tertiary butyl.