Abstract: Novel growth hormone releasing factor analogs are presented having a sequence of from about twenty-nine (29) to about forty-four (44) amino acids (SEQ ID NO: 6) wherein Xaa at position 1 is His, 3-MeHis, desNH.sub.2 His, Tyr, or desNH.sub.2 Tyr; Xaa at position 2 is Val, Leu, lie, Ala, D-Ala, N-Methyl-D-Ala, Gly, NIe, or Nval; Xaa at position 8 is Gln, Ser, or Thr; Xaa at position 15 is Ala or Leu; Xaa at position 27 is Met, Nle or Leu; Xaa at position 28 is Ser or Asn; Xaa at position 29 is an amino acid residue sequence (SEQ ID NO: 7) or fragments thereof where the fragment is reduced in number by one to fifteen amino acid residues from the carboxyl-terminus, where the carboxyl terminus can be the free carboxylic acid or the corresponding amide, and the pharmaceutically acceptable acid or base addition salts thereof.

Abstract: Novel growth hormone releasing factor analogs are presented having the formula: ##STR1## wherein R.sub.1 is His, 3-MeHis, desNH.sub.2 His, Tyr, or desNH.sub.2 Tyr; R.sub.2 is Val, Leu, or Ile; R.sub.3 is Ala; R.sub.4 is Met, Leu, Ile, or Nle; R.sub.5 is Ser or Asn; R.sub.6 is an amino acid residue sequence selected from Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu or fragments thereof where the fragment is reduced in number by one to fifteen amino acid residues from the amino acid residue which carries the substituent X; and X is either OH or NH.sub.2, and the pharmaceutically acceptable acid or base addition salts thereof. The novel growth hormone releasing factor analogs demonstrate enhanced potency for the released growth hormone, have enhanced enzymatic stability, and can be administered to a subject having a deficiency of growth hormone or for improvement of growth performance in livestock.

Abstract: A sensitive immunoassay for acetylcholine is described. To prepare the acetylcholine selective antiserum, an antigen is made comprising 6-aminocaproic acid (2-trimethylaminoethyl) ester covalently bonded to an immunogenic carrier material through a peptide bond formed from said 6-amino group and carboxyl groups contained in said immunogenic carrier material and the antigen is injected into a suitable host animal to elicit the desired antiserum.

Abstract: D,L-3,4-dehydroproline is resolved in high optical yield by conversion to its N-protected derivative, treatment with R(+)alpha-methyl-p-nitrobenzylamine to form the diastereomeric salts, fractional crystallization, decomposition of the L-R salt and regeneration of the secondary amine group. The product L-3,4-dehydroproline obtained in extremely high optical purity is useful as an inhibitor of collagen synthesis.

Abstract: Radiolabelled and isotopically labelled peptides are prepared in a convenient and efficient manner by catalytically tritiating or deuterating an analog of the desired peptide containing one or more amino acid residues having an ethylenic type unsaturated bond therein. Preferred amino acid residues for this purpose include 3,4-dehydroproline (.DELTA..sup.3 -proline) and trans-4,5-dehydrolysine (.DELTA..sup.4 -lysine).