Abstract: The present invention discloses novel gonadal peptides with inhibin-like activity. The novel peptides include two gonadal peptides, one consisting of 52 amino acids, the other consisting of 92 amino acids. Both of these peptides were initially isolated from human seminal plasma. Both have now been chemically synthesized. The novel peptides are designated as alpha-inhibin-52 and alpha-inhibin-92. Sequence analyses show that the NH.sub.2 -terminal 31 amino acids of alpha-inhibin-52 are identical to the structure of the 31 amino acid inhibin-like peptide previously reported by Ramasharma, et al. (1984). Sequence analyses also show that the COOH-terminal 52 amino acids of alpha-inhibin-92 are identical to the structure of alpha-inhibin-52. The amino acid sequence of alpha-inhibin-92 is: ##STR1## .

Abstract: The solid-phase syntheses of [Ala.sup.2 ]-, [D-Leu.sup.2 ]-, [D-Lys.sup.2 ], [Leu.sup.5 ]- and [D-Ala.sup.2, D-Leu.sup.5 ] .beta.-endorphins are described. The synthetic peptides were purified by chromatography on carboxymethylcellulose and partition chromatography on Sephadex G-50. They were characterized by partition chromatography on agarose, thin-layer chromatography, paper electrophoresis, and amino acid analyses of acid and enzymic hydrolysates. Bioassay of the synthetic analogs for analgesic activity by the tail-flick-method showed the D-Leu.sup.2 analog to be 48% as potent as .beta..sub.h -endorphin while the Ala.sup.2, D-Lys.sup.2, Leu.sup.5, and [D-Ala.sup.2, D-Leu.sup.5 ] analogs were 8 to 17% as active.

Abstract: Novel carboxyl terminus analogs of .beta.-endorphin are described. The carboxyl terminus of such analogs is selected from lower alkyl amide, glycine, glycinamide, or polyglycine. These analogs exhibit either greater analgesic activity than the parent .beta.-endorphin and/or increased binding activity in an opiate binding assay.

Abstract: Tritiated .beta.-endorphin is prepared by catalytic tritiation of a [3,5-diido-Tyr]-.beta.-endorphin which in turn is readily obtained by solid phase synthesis. The tritiated .beta.-endorphin preferably [3,5-diiodo-Tyr.sup.27 ]-.beta.-endorphin may be utilized as a radio-labelled tracer compound in radioimmunoassay for .beta.-endorphin and also exhibits biological activity comparable to that of the native .beta.-endorphin.

Abstract: Non-covalent complementation of peptide hormonal fragments produces a recombinant with the hormonal activity of the native hormone. The fragments employed can be natural, synthetic or mixed natural-synthetic origin and can contain less than the total amino acid sequence of the native hormone or fragments derived from related hormones. In a preferred embodiment the human growth hormone (HGH) fragments [Cys(Cam).sup.53 -HGH-(1-134)] and [Cys(Cam).sup.165,182,189 -HGH-(141-191)] undergo non-covalent complementation to yield a recombinant having full growth-promoting and prolactin potency of the native human growth hormone.

Abstract: An untriakontapeptide having significant opiate agonist activity has been isolated from camel pituitary glands. The structure of this peptide has been determined and this peptide was then synthesized utilizing solid phase peptide synthesis. Both natural and synthetic material show identical physical and biological properties.