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A new series of CB(1) receptor antagonists incorporating an imidazole-based isosteric replacement for the hydrazide moiety of rimonabant (SR141716) is disclosed. Members of this imidazole series possess potent/selective binding to the rCB(1) receptor and exhibit potent hCB(1) functional activity. Isopropyl analog 9a demonstrated activity in the tetrad assay and was orally-active in a food intake model.

We report the structure-activity relationships, design, and synthesis of the novel cannabinoid type 1 (CB1) receptor antagonist 3a (CP-945,598). Compound 3a showed subnanomolar potency at human CB1 receptors in binding (Ki = 0.7 nM) and functional assays (Ki = 0.12 nM). In vivo, compound 3a reversed cannabinoid agonist-mediated responses, reduced food intake, and increased energy expenditure and fat oxidation in rodents.

Growth hormone secretagogues (GHSs) represent attractive therapeutic alternatives to recombinant growth hormone (GH), given their ability to amplify pulsatile hormone secretion in a relatively physiologic manner. CP-424,391 (391) is a novel, orally active pyrazolinone-piperidine [corrected] GHS. In rat pituitary cell cultures, 391 stimulated GH release with an EC50 = 3 nM. The addition of 391 to rat pituitary cells activated intracellular calcium signaling but did not elevate intracellular cyclic adenosine monophosphate (cAMP). 391 also modulated the effects of GH-releasing hormone and somatostatin on pituitary cell GH-release and intracellular signaling. In nonpituitary cell lines, the ability of 391 to stimulate intracellular signaling was dependent on the expression of recombinant human GHS receptor. Acute administration of 391 to anesthetized rats or to conscious dogs induced pulsatile release of G H in a dose-dependent manner. Plasma insulin-like growth factor-I (IGF-I) was elevated progressively over a 5-d course of daily oral dosing in dogs. Chronic oral administration of 391 augmented body weight gain in rats and dogs. Thus, the peptidomimetic GHS 391 has potential utility for the treatment of clinical conditions that could benefit from systemic augmentation of GH and IGF-I levels.