Oxytocin (OXT) has been shown to suppress appetite, induce weight loss, and improve glycemic control and lipid metabolism in several species, including humans, monkeys, and rodents. However, OXT’s short half-life in circulation and lack of receptor selectivity limit its application and efficacy. In this study, we report an OXT peptide analog (OXTGly) that is potent and selective for the OXT receptor (OXTR). OXT, but not OXTGly, activated vasopressin receptors in vitro and acutely increased blood pressure in vivo when administered IP. OXT suppressed food intake in mice, whereas OXTGly had a moderate effect on food intake when administered IP or intracerebroventricularly. Both OXT (IP) and OXTGly (IP) improved glycemic control in glucose tolerance tests. Additionally, both OXT (IP) and OXTGly (IP) stimulated insulin, glucagon-like peptide 1, and glucagon secretion in mice. We generated lipid-conjugated OXT (acylated-OXT) and OXTGly (acylated-OXTGly) and demonstrated that these molecules have significantly extended half-lives in vivo. Compared with OXT, 2-week treatment of diet-induced obese mice with acylated-OXT [subcutaneous(ly) (SC)] resulted in enhanced body weight reduction, an improved lipid profile, and gene expression changes consistent with increased lipolysis and decreased gluconeogenesis. Treatment with acylated-OXTGly (SC) also resulted in a statistically significant weight loss, albeit to a lesser degree compared with acylated-OXT treatment. In conclusion, we demonstrate that selective activation of the OXTR pathway results in both acute and chronic metabolic benefits, whereas potential activation of vasopressin receptors by nonselective OXT analogs causes physiological stress that contributes to additional weight loss.

Objective Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are effective medications to reduce appetite and body weight. These actions are centrally mediated; however, the neuronal substrates involved are poorly understood. Methods We employed a combination of neuroanatomical, genetic, and behavioral approaches in the mouse to investigate the involvement of caudal brainstem cholecystokinin-expressing neurons in the effect of the GLP-1RA exendin-4. We further confirmed key neuroanatomical findings in the non-human primate brain. Results We found that cholecystokinin-expressing neurons in the caudal brainstem are required for the anorectic and body weight-lowering effects of GLP-1RAs and for the induction of GLP-1RA-induced conditioned taste avoidance. We further show that, while cholecystokinin-expressing neurons are not a direct target for glucose-dependent insulinotropic peptide (GIP), GIP receptor activation results in a reduced recruitment of these GLP-1RA-responsive neurons and a selective reduction of conditioned taste avoidance. Conclusions In addition to disclosing a neuronal population required for the full appetite- and body weight-lowering effect of GLP-1RAs, our data also provide a novel framework for understanding and ameliorating GLP-1RA-induced nausea — a major factor for withdrawal from treatment.

The induction of nausea and emesis is a major barrier to maximizing the weight loss profile of obesity medications, and therefore, identifying mechanisms that improve tolerability could result in added therapeutic benefit. The development of Peptide YY (PYY)-based approaches to treat obesity are no exception, as PYY receptor agonism is often accompanied by nausea and vomiting. Here, we sought to determine whether glucose-dependent insulinotropic polypeptide (GIP) receptor agonism reduces PYY-induced nausea-like behavior in mice. We found that central and peripheral administration of a GIPR agonist (GIPRA) reduced conditioned taste avoidance (CTA) without affecting hypophagia induced by a PYY analog. The receptors for GIP and PYY (Gipr and Npy2r) were expressed by the same neurons in the area postrema (AP), a brainstem nucleus involved in the detection of aversive stimuli. Peripheral administration of a GIPRA induced neuronal activation (cFOS) in the AP. Further, whole-brain cFOS analyses indicated that PYY-induced CTA was associated with augmented neuronal activity in the parabrachial nucleus (PBN), an area of the brain that relays aversive/emetic stimuli to brain regions that control feeding behavior. Importantly, GIPR agonism reduced PYY-mediated neuronal activity in the PBN, providing a potential mechanistic explanation for how GIPRA treatment reduces PYY-induced nausea-like behavior. Together, our study provides a novel mechanism by which GIP-based therapeutics may benefit the tolerability of weight loss agents.

The prostate responds to deleterious inflammation with induction of cell survival mechanisms, most notably survivin and autophagy, demonstrating a coordinated induction of survival factors that protects and expands a specialized set of prostatic epithelial cells as part of the repair and recovery process during inflammation.

<p>The induction of nausea and emesis is a major barrier to maximizing the weight loss profile of obesity medications, and therefore, identifying mechanisms that improve tolerability could result in added therapeutic benefit. The development of Peptide YY (PYY)-based approaches to treat obesity are no exception, as PYY receptor agonism is often accompanied by nausea and vomiting. Here, we sought to determine whether glucose-dependent insulinotropic polypeptide (GIP) receptor agonism reduces PYY-induced nausea-like behavior in mice. We found that central and peripheral administration of a GIPR agonist (GIPRA) reduced conditioned taste avoidance (CTA) without affecting hypophagia mediated by a PYY analog. The receptors for GIP and PYY (<em>Gipr</em> and <em>Npy2r</em>) were found to be expressed by the same neurons in the area postrema (AP), a brainstem nucleus involved in detecting aversive stimuli. Peripheral administration of a GIPRA induced neuronal activation (cFos) in the AP. Further, whole-brain cFos analyses indicated that PYY-induced CTA was associated with augmented neuronal activity in the parabrachial nucleus (PBN), a brainstem nucleus that relays aversive/emetic signals to brain regions that control feeding behavior. Importantly, GIPR agonism reduced PYY-mediated neuronal activity in the PBN, providing a potential mechanistic explanation for how GIPRA treatment reduces PYY-induced nausea-like behavior. Together, our study provides a novel mechanism by which GIP-based therapeutics may benefit the tolerability of weight loss agents. </p>