Unfortunately, the available data that address this hypothesis are sparse due to the challenge of studying an adequate number of social groups. Depressive behavior may be only one in a range of potential responses to social subordination stress. Studying the attributes of subordinates that do not become depressed may provide valuable insights about alternative stress responses. Single caging may be considered a stressor as selleck products it increases heart rate in adult female cynomolgus monkeys (Watson et al., Apr 1998). We measured circulating biomarkers and heart rate (HR) in single caged monkeys immediately prior to social housing. Females that had higher overnight HRs in single cages were later more likely to exhibit behavioral
depression in social groups, suggesting that stress sensitivity may increase the likelihood of a depressive response to social stress (Shively et al., Sep–Oct 2002). Likewise the monkeys that later developed behavioral depression in social groups had decreased cortisol secretion in a corticotropin-releasing hormone (CRH) challenge test, decreased circulating insulin-like growth factor-1 (IGF-1) concentrations, lower activity levels,
Selleck Metformin and higher total plasma cholesterol (TPC) concentrations and ratios of TPC:high-density lipoprotein cholesterol (HDL-C) concentrations while singly caged. These data suggest that individuals at increased risk for a depressive response to social stress also differ in a number of
physiological systems associated with increased disease risk (Shively et al., Apr 2005). In a study of 46 ovariectomized cynomolgus monkeys, whatever socially subordinate females had increased cell proliferation and proportions of glandular and epithelial tissue, and less stroma in endometrium, and increased breast tissue thickness than their dominant counterparts (Shively et al., Jul–Aug 2004). These tissue characteristics are associated with increased risk of endometrial and breast cancer in women (Nucci et al., Mar 2003 and Ursin et al., Apr 2003). Socially dominant rhesus macaques live longer than their subordinate counterparts (Blomquist et al., 2011). Likewise, low social status is associated with increased mortality in the human population (Adler, Nov 2009 and Adler et al., Jan 1994). There is reason to believe that diet composition may modulate stress responses. For example, rats consuming a high fat diet have a higher cortisol response to stress compared to rats consuming a low fat diet (Legendre and Harris, Nov 2006). Likewise, chronic variable stress exaggerates the lipid response to a high fat diet (Manting et al., 2011). In clinical studies, consuming a high fat meal (mostly saturated animal fat) acutely exaggerates cardiovascular responses to stress (Jakulj et al., Apr 2007). Such responses have been shown to be attenuated in short term studies by consuming diets rich in polyunsaturated fats derived from plant sources (e.g.