GRF analogs VI

A method of stimulating the release of growth hormone in an animal, which comprises administering to said animal an effective amount of a peptide, or a nontoxic salt thereof, having the sequence:

• R.sub.1 -R.sub.2 -R.sub.3 -R.sub.4 -R.sub.5 -Phe-R.sub.7 -R.sub.8 -R.sub.9 -Tyr-Arg-R.sub.12 -R.sub.13 -Leu-R.sub.15 -Gln-Leu-R.sub.1 27 -R.sub.28 -R.sub.29 -R.sub.30 -R.sub.31 -Gly-R.sub.33 -R.sub.34 -R.sub.35 -R.sub.36 -R.sub.37 -R.sub.38 -R.sub.39 -R.sub.40 -R.sub.41 -R.sub.42 -R.sub.43 -R.sub.44 -Ser wherein R.sub.1 is N-Me Tyr, Tyr, desNH.sub.2 -Tyr, D-Tyr, N-Et Tyr, N-Ip Tyr, N-Me His, His, desNH.sub.2 -His, D-His, N-Et His, and N-Ip His;
• R.sub.2 is Ala, D-Ala or D-NMA;
• R.sub.3 is Asp or D-Asp;
• R.sub.4 is Gly or Ala;
• R.sub.5 and R.sub.27 are selected from the group consisting of Met, Leu, Val, Nva, Gln, Thr, Ile, Ala, Arg, Asn, Asp, Cys, Glu, Gly, His, Nle, Lys, Phe, Pro, Ser, Tyr and Trp;
• R.sub.7 is Asn or Thr;
• R.sub.8 is Lys, Asn or Ser;
• R.sub.9 is Ala or Ser;
• R.sub.12 is Lys or Arg;
• R.sub.13 is Ala, Val or Ile;
• R.sub.15 is Gly or Ala;
• R.sub.18 is Ser or Tyr;
• R.sub.22 is Tyr or Leu;
• R.sub.24 is His or Gln;
• R.sub.25 is Thr, Asp, or Glu;
• R.sub.26 is Leu or Ile;
• R.sub.28 is Ala, Ser or Asn;
• R.sub.29 is Lys or Arg;
• R.sub.30 is Arg or Gln;
• R.sub.31 is Val or Gln;
• R.sub.33 is Gly or Glu;
• R.sub.34 is Gly, Arg or Ser;
• R.sub.35 is Ser or Asn;
• R.sub.36 is Met, Leu, Val, Nva, Gln, Thr, Ile or Nle;
• R.sub.37 is Ile or Glu;
• R.sub.38 is Glu, Gln or Arg;
• R.sub.39 is Asp, Arg or Gly;
• R.sub.40 is Asp, Ser or Ala;
• R.sub.41 is Asn, Arg or Lys;
• R.sub.42 is Glu, Phe, Ala or Val;
• R.sub.43 is Pro, Asn or Arg;
• R.sub.44 is Leu or Ala;
• provided however that at least one of the following is present:
• R.sub.7 is Asn, R.sub.8 is Lys, R.sub.13 is Ala, R.sub.22 is Tyr and R.sub.25 is Thr;
• and provided further that any or all of the residues after R.sub.27 may be deleted.

A peptide, or a nontoxic salt thereof, which is useful in accelerating growth in fish and other cold-blooded animals, which peptide has the formula:

• R.sub.1 -R.sub.2 -R.sub.3 -Gly-R.sub.5 -Phe-Asn-Lys-Ala-Tyr-Arg-Lys-Ala-Leu-R.sub.15 -Gln-Leu-Ser-Ala-Arg-Lys-Tyr-Leu-His-Thr-Leu-R.sub.27 -R.sub.28 -R.sub.29 -R.sub.30 -R.sub.31 -NHR wherein R.sub.1 is N-Me Tyr, N-Me His, N-Et Tyr, N-Et His, N-Ip His or N-Ip Tyr;
• R.sub.2 is Ala or D-Ala;
• R.sub.3 is Asp or D-Asp;
• R.sub.5 is Met, Nva or Nle;
• R.sub.15 is Gly or Ala;
• R.sub.27 is Nva or Nle;
• R.sub.28 is Ala, Ser, Asn or des-R.sub.28;
• R.sub.29 is Lys or Arg or des-R.sub.29 ;
• R.sub.30 is Arg or Gln or des-R.sub.30 ;
• and R.sub.31 is Val or Gln or des-R.sub.31 ;
• and R is H or lower alkyl.