(39)), by contrast, Y2 receptors have not been detected on bone. In addition to effects in bone, Y1 receptors have been considered as important regulators of energy homeostasis, consistent with pharmacological evidence from Y receptor agonists and antagonists to stimulate or inhibit feeding (9). Fasting-induced re-feeding is reduced in germ line Y1 receptor knock-out mice (10), and deletion of Y1 receptors in genetically obese ob/ob mice, in which hypothalamic NPY-ergic activity is chronically increased, significantly reduces food intake and body weight (11). Paradoxically, germ line Y1 receptor knock-out mice develop late-onset obesity in the absence of hyperphagia (10,12,13). One hypothesis to reconcile this apparent discrepancy is that hypothalamic and non-hypothalamic Y1 receptors have different effects on energy homeostasis.Given the clear involvement of Y1 receptors in the regulation of energy homeostasis as well as new evidence of a putative role for Y1 receptors on osteoblast-like cells, we investigated the effect of germ line and conditional (adult-onset, hypothalamus-specific) deletion of Y1 receptors in mice. In addition, the potential interaction between Y1 receptor sig-

Box 1 | Prevailing attitudes of medical professionals emerging from public review and participant survey Agreement with goal of standardizing nomenclature, with acknowledgment of challenges Regarded multiplicity of terms and lack of adherence to established definitions as confusing and potentially leading to errors Anticipated that a standardized nomenclature would help foster consistency in trial design, execution, and reporting Judged consistency between terms used in scholarly and patient communities to be an important goal, but not one overriding the need for precision and efficiency Journal editors strongly agreed that having a more standardized nomenclature for kidney disease would be useful for their journals, but they anticipated time constraints of journal personnel to be the biggest barrier to implementation Qualified endorsement of replacing "renal" with "kidney" Felt that foregrounding "kidney" would be easier for patients and their families Perceived a greater likelihood of raising awareness, attracting funding, and influencing public policy with consistent use of "kidney" Cautioned against a wholesale switch because "renal" may be less awkward in some contexts and may be necessary in others (e.g., ESRD as a CMS definition) Dissatisfaction with "end-stage" as a descriptor of kidney disease Recognized that this wording can be demoralizing and stigmatizing for patients Considered the implication of imminent death to be outdated Frustrated by imprecision in its use (ranging from being a synonym for dialysis patients to a descriptor of patients with kidney failure with or without kidney replacement therapy) Recognition of the need for ongoing attention to nomenclature issues Noted that standardization of nomenclature is dependent on uptake of consensus definitions B where definitions are in flux or are more contentious, standardization of that nomenclature set may be premature B enhancing adoption of definitions requires continued effort Highlighted the need for harmonization with ongoing, broader-scope ontology efforts Expected that improved understanding of molecular mechanisms will lead to more-precise definitions and nomenclature CMS, Centers for Medicare & Medicaid Services; ESRD, end-stage renal disease.

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