RESUMO
This article is part of a Special Issue "Energy Balance". Natural populations display a variety of reproductive responses to environmental cues, but the underlying physiology that causes these responses is largely unknown. This study tested the hypothesis that heritable variation in reproductive traits can be described by heritable variation in concentrations of hormones critical to both energy balance and reproduction. To test this hypothesis, we used mouse lines derived from a wild population and selectively bred for response to short day photoperiod. Reproductive and metabolic traits of Peromyscus leucopus display heritable variation when held in short photoperiods typical of winter. Our two lines of mice have phenotypes spanning the full range of variation observed in nature in winter. We tested male and female mice for heritable variation in fasted serum concentrations of three hormones involved in energetic regulation: leptin, insulin-like growth factor 1 (IGF-1) and insulin, as well as the effects of exogenous leptin and a high energy diet on reproductive maturation. Exogenous leptin decreased food intake, but protected males from the reduction in testis mass caused by equivalent food restriction in pair-fed, saline-infused controls. A high energy diet resulted in calorie adjustment by the mice, and failed to alter reproductive phenotype. Concentrations of the three hormones did not differ significantly between selection lines but had correlations with measures of food intake, fertility, blood glucose, and/or body mass. There was evidence of interactions between reproductive traits and hormones related to energy balance and reproduction, but this study did not find evidence that variation in these hormones caused variation in reproductive phenotype.
Assuntos
Metabolismo Energético/fisiologia , Insulina/sangue , Leptina/sangue , Peromyscus/fisiologia , Reprodução/fisiologia , Animais , Ingestão de Alimentos/fisiologia , Feminino , Fertilidade/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Leptina/farmacologia , Masculino , Fenótipo , FotoperíodoRESUMO
OBJECTIVE: To examine long-term care facility (LTCF or nursing home) use and end-of-life care for individuals with Parkinson disease (PD). METHODS: In this nationwide retrospective cohort study, we compared LTCF and hospice utilization among Medicare beneficiaries diagnosed with PD by demographic, clinical, and physician characteristics. We also examined the impact of outpatient neurologist care for institutionalized patients with PD on end-of-life care. RESULTS: We identified 469,055 individuals with PD who received Medicare benefits in 2002. Nearly 25% (more than 100,000 in total) resided in an LTCF. Women with PD had greater odds of nursing facility residence (adjusted odds ratio [AOR] 1.34, 95% confidence interval [CI] 1.30-1.38) compared with men. Black individuals with PD were 34% more likely than white individuals to reside in an LTCF (AOR 1.34, 95% CI 1.30-1.38), contrary to the race patterns typically observed for LTCF use. Hip fracture (AOR 2.10, 95% CI 2.04-2.15) and dementia (AOR 4.06, 95% CI 4.00-4.12) were the strongest clinical predictors of LTCF placement. Only 33% (n = 38,334) of nursing home residents with PD had outpatient neurologist care. Eighty-four percent (n = 80,877) of LTCF residents with PD died by December 31, 2005. Hospice utilization varied little by race and sex. LTCF residents who had outpatient neurologist care were twice as likely to utilize hospice services before death (AOR 2.35, 95% CI 2.24-2.47). CONCLUSIONS AND RELEVANCE: A large proportion of the Medicare PD population resides in an LTCF. There is substantial unmet need for palliative care in the PD population. Increased efforts to provide specialist care to dependent individuals with PD may improve end-of-life care.