Abstract: [im-Bzl D-His.sup.6 ]LRF and [D-His.sup.6 (im-Bzl), Pro.sup.9 -NEt]LRF exhibit hydrophillicity comparable to that of LRF and act as superagonists exhibiting potencies, respectively, about 12 and more than 200 times that of LRF. The peptides or their nontoxic salts can be administered by intravenous subcutaneous, sublingual, oral, intravaginal, intranasal or rectal routes. The peptides can be used to regulate fertility in male and female mammals, including human beings.

Abstract: A method for preventing reproduction by administering to male mammals a peptide which inhibits the secretion of gonadotropins by the pituitary gland and inhibits the release of steroids by the gonads. The peptide has the structure:p--Glu--His--Trp--Ser--Tyr--D--Trp--Leu--Arg--Pro--NH--CH.sub.2 --CH.sub.3.

Abstract: Peptides which inhibit the secretion of gonadotropins by the pituitary gland and inhibit the release of steroids by the gonads. The peptides have the structure:R.sub.1 --R.sub.2 --R.sub.3 --Ser--Tyr--R.sub.4 --R.sub.5 --Arg--R.sub.6wherein R.sub.1 is selected from the group consisting of D-pGlu, D-Pro, D-Trp, D-His, D-Arg, D-Leu, Formyl D-Pro, Acetyl D-Pro, Benzoyl D-Pro and .beta.-Ala; R.sub.2 is selected from the group consisting of D-Phe, Phe, N.alpha. Me-Phe, His, D-His, D-Trp, Trp and N.alpha. Me-Leu; R.sub.3 is selected from the group consisting of D-Trp, Trp; D-Phe, Phe, Pro and D-His; R.sub.4 is selected from the group consisting of Gly, D-Trp, D-Phe and D-Tyr; R.sub.5 is selected from the group consisting of Leu and N.alpha. Me Leu; and R.sub.6 is selected from the group consisting of Pro-Gly-NH.sub.2 and Pro--NH--CH.sub.2 --CH.sub.3.

Abstract: Somatostatin peptides are modified by substitution of para-methoxylated Phe or para-halogenated Phe for any Phe in the peptide. The modified somatostatin peptide analogs have the formulae: ##STR1## wherein R is hydrogen or an acyl group; R.sub.1 is selected from the group consisting of Lys or Des R.sub.1 ; R.sub.2 is selected from the group consisting of Asn, Ala or Des R.sub.2. The amino acids of the R.sub.2 group can be either the L-form or the D-form; R.sub.3 is selected from the group consisting of Trp or D-Trp; R.sub.4 is selected from the group consisting of Thr or Des R.sub.4 ; R.sub.5 is selected from the group consisting of Ser, D-Ser, Phe, X or Des R.sub.5 ; and X is selected from the group consisting of Phe, para-halogenated Phe and para-methoxylated Phe. Provided that at least one X is either para-halogenated Phe or para-methoxylated Phe.

Abstract: Peptides having thermoregulative properties when administered to animals. The peptides are identified by the structure:R.sub.1 -R.sub.2 -Trp-Ala-Val-R.sub.3 -His-R.sub.4 -R.sub.5 -NH.sub.2 wherein: R.sub.1 is selected from the group consisting of hydrogen, an amino acid selected from the group consisting of p-Glu,Gln,Arg,Leu,Gly,Asn,Thr,Val, and Pro, and peptides having from 2 to 6 amino acids wherein the amino acids are selected from p-Glu,Gln,Arg,Leu,Gly,Asn,Thr,Val, and Pro, provided that when p-Glu is part of R.sub.1, p-Glu is located at the N terminus of the peptide; R.sub.2 is selected from the group consisting of D-pGlu, D-Gln and Gln; R.sub.3 is selected from the group consisting of D-Ala and Gly; R.sub.4 is selected from the group consisting of Phe and Leu and R.sub.5 is selected from Met and D-Met. Intermediates of the peptides are also provided.

Abstract: The present invention relates to peptides having dissociated biological activity in respect to the inhibition of growth hormone, insulin, and glucagon secretion. The peptides are analogs of somatostatin.

Abstract: The present invention relates to peptides which possess biological activity in respect to the inhibition of growth hormone, insulin secretion and glucagon secretion are provided. The peptides have fewer amino acid components than somatostatin and some of the peptides have dissociated activity.

Abstract: Peptides have been synthesized which influence the secretion of gonadotropins by the pituitary gland of mammalians, including humans. Some of the peptides promote the release of gonadotropins, while other peptides inhibit the release.

Abstract: The present invention relates to peptides which possess biological activity in respect to the inhibition of growth hormone, insulin .[.secretion.]. and glucagon secretion .[.are provided.].. The peptides have fewer amino acid components than somatostatin and some of the peptides have dissociated activity. .Iadd.