title: The stress of growing old: sex- and season-specific effects of age on allostatic load in wild grey mouse lemurs.
abstract: Chronic stress [i.e. long-term elevation of glucocorticoid (GC) levels] and aging have similar, negative effects on the functioning of an organism. Aged individuals' declining ability to regulate GC levels may therefore impair their ability to cope with stress, as found in humans. The coping of aged animals with long-term natural stressors is virtually unstudied, even though the ability to respond appropriately to stressors is likely integral to the reproduction and survival of wild animals. To assess the effect of age on coping with naturally fluctuating energetic demands, we measured stress hormone output via GC metabolites in faecal samples (fGCM) of wild grey mouse lemurs (Microcebus murinus) in different ecological seasons. Aged individuals were expected to exhibit elevated fGCM levels under energetically demanding conditions. In line with this prediction, we found a positive age effect in the dry season, when food and water availability are low and mating takes place, suggesting impaired coping of aged wild animals. The age effect was significantly stronger in females, the longer-lived sex. Body mass of males but not females correlated positively with fGCM in the dry season. Age or body mass did not influence fGCM significantly in the rainy season. The sex- and season-specific predictors of fGCM may reflect the differential investment of males and females into reproduction and longevity. A review of prior research indicates contradictory aging patterns in GC regulation across and even within species. The context of sampling may influence the likelihood of detecting senescent declines in GC functioning.
authors.affiliation: Department of Sociobiology/Anthropology, University of Göttingen, Kellnerweg 6, 37077, Göttingen, Germany, anni.m.hamalainen@gmail.com.
authors.forename: Anni
authors.initials: A
authors.lastname: Hämäläinen
authors.forename: Michael
authors.initials: M
authors.lastname: Heistermann
authors.forename: Cornelia
authors.initials: C
authors.lastname: Kraus
mesh_terms: D000375:Aging; D052636:Allostasis; D000818:Animals; D000835:Animals, Wild; D001835:Body Weight; D016565:Cheirogaleidae; D005243:Feces / Q000737:chemistry; D005260:Female; D005938:Glucocorticoids / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D012098:Reproduction; D012621:Seasons; D012737:Sex Factors; D013312:Stress, Physiological
chemical_list: D005938:Glucocorticoids
references.citation: Horm Behav. 2008 Aug;54(3):410-6
references.pmid: 18514196
references.citation: Proc Biol Sci. 2010 Oct 22;277(1697):3203-12
references.pmid: 20554550
references.citation: Behav Brain Res. 2010 Aug 25;211(2):169-77
references.pmid: 20307586
references.citation: Mech Ageing Dev. 2002 Apr 30;123(8):1191-201
references.pmid: 12044968
references.citation: Nat Rev Immunol. 2005 Mar;5(3):243-51
references.pmid: 15738954
references.citation: Endocr Rev. 1986 Aug;7(3):284-301
references.pmid: 3527687
references.citation: Neuroscience. 2009 Mar 3;159(1):259-70
references.pmid: 19141312
references.citation: Gen Comp Endocrinol. 2014 May 1;200:54-60
references.pmid: 24607571
references.citation: Neurobiol Aging. 2001 Mar-Apr;22(2):323-32
references.pmid: 11182482
references.citation: Proc Biol Sci. 2014 Sep 22;281(1791):20140830
references.pmid: 25100693
references.citation: J Clin Endocrinol Metab. 2000 Jul;85(7):2556-63
references.pmid: 10902808
references.citation: Horm Behav. 1994 Dec;28(4):464-76
references.pmid: 7729815
references.citation: Ageing Res Rev. 2012 Jan;11(1):150-62
references.pmid: 21802530
references.citation: Proc Natl Acad Sci U S A. 1984 Oct;81(19):6174-7
references.pmid: 6592609
references.citation: Neurosci Biobehav Rev. 2010 Sep;35(1):2-16
references.pmid: 19822172
references.citation: J Gerontol A Biol Sci Med Sci. 1997 Mar;52(2):M68-75
references.pmid: 9060972
references.citation: Biol Lett. 2005 Mar 22;1(1):60-3
references.pmid: 17148128
references.citation: Exp Gerontol. 2003 Apr;38(4):407-14
references.pmid: 12670627
references.citation: Gen Comp Endocrinol. 2014 Jan 1;195:68-79
references.pmid: 24212051
references.citation: Neurobiol Aging. 1998 Jul-Aug;19(4):363-6
references.pmid: 9733169
references.citation: Psychoneuroendocrinology. 2009 Jan;34(1):2-18
references.pmid: 19041187
references.citation: Exp Gerontol. 1983;18(1):55-64
references.pmid: 6683660
references.citation: J Anim Ecol. 2007 Nov;76(6):1181-91
references.pmid: 17922714
references.citation: J Anim Ecol. 2009 Nov;78(6):1249-58
references.pmid: 19426257
references.citation: Endocrinology. 1961 May;68:818-24
references.pmid: 13756461
references.citation: J Steroid Biochem Mol Biol. 1991;40(1-3):63-9
references.pmid: 1659883
references.citation: Endocrinology. 1993 Jan;132(1):161-8
references.pmid: 8380372
references.citation: Proc Natl Acad Sci U S A. 2010 Apr 6;107(14):6370-5
references.pmid: 20308547
references.citation: Gen Comp Endocrinol. 2002 Aug;128(1):1-24
references.pmid: 12270784
references.citation: Mech Ageing Dev. 1993 Jun;69(1-2):93-107
references.pmid: 8104261
references.citation: Neurobiol Aging. 1983 Summer;4(2):133-8
references.pmid: 6685230
references.citation: Biol Psychol. 2005 Apr;69(1):113-32
references.pmid: 15740829
references.citation: Psychoneuroendocrinology. 2005 Jan;30(1):80-91
references.pmid: 15358445
references.citation: Neurobiol Aging. 2004 Aug;25(7):893-904
references.pmid: 15212843
references.citation: Endocrinology. 2005 Jul;146(7):3105-12
references.pmid: 15831572
references.citation: Exp Gerontol. 2015 Jan;61:54-61
references.pmid: 25446501
references.citation: J Evol Biol. 2014 Feb;27(2):259-74
references.pmid: 24341364
references.citation: Biol Psychiatry. 1991 Nov 15;30(10):1008-16
references.pmid: 1756195
references.citation: Neurobiol Aging. 1992 Jan-Feb;13(1):171-4
references.pmid: 1542376
references.citation: Endocrinol Metab Clin North Am. 2013 Jun;42(2):201-25
references.pmid: 23702398
references.citation: Endocr Rev. 2000 Feb;21(1):55-89
references.pmid: 10696570
references.citation: Proc Biol Sci. 2008 Jul 22;275(1643):1635-44
references.pmid: 18426751
references.citation: Gen Comp Endocrinol. 2003 Nov;134(2):156-66
references.pmid: 14511986
references.citation: J Behav Med. 2006 Aug;29(4):389-400
references.pmid: 16715331
references.citation: Trends Ecol Evol. 2009 Nov;24(11):634-42
references.pmid: 19679371
references.citation: Am Nat. 2009 May;173(5):589-98
references.pmid: 19281425
references.citation: Gen Comp Endocrinol. 2006 Sep 1;148(2):132-49
references.pmid: 16624311
references.citation: Gen Comp Endocrinol. 2011 Sep 15;173(3):461-6
references.pmid: 21827761
references.citation: N Engl J Med. 1998 Jan 15;338(3):171-9
references.pmid: 9428819
references.citation: Gen Comp Endocrinol. 2009 Sep 1;163(1-2):208-13
references.pmid: 19135999
references.citation: Ecology. 2011 Oct;92(10):1936-47
references.pmid: 22073785
references.citation: Gen Comp Endocrinol. 2006 Oct;149(1):1-9
references.pmid: 16750533
references.citation: Horm Behav. 2014 Nov;66(5):828-37
references.pmid: 25448533
references.citation: Horm Behav. 2007 Mar;51(3):313-20
references.pmid: 17258747
references.citation: J Neuroendocrinol. 2003 Aug;15(8):711-24
references.pmid: 12834431
references.citation: Proc Biol Sci. 2006 Sep 7;273(1598):2227-31
references.pmid: 16901843
references.citation: Oecologia. 2011 Aug;166(4):869-87
references.pmid: 21344254
references.citation: Neurobiol Aging. 1994 Mar-Apr;15(2):227-31
references.pmid: 7838296
references.citation: Neurosci Biobehav Rev. 2011 Apr;35(5):1291-301
references.pmid: 21316391
references.citation: Gen Comp Endocrinol. 2008 May 1;156(3):564-8
references.pmid: 18378235
references.citation: Horm Behav. 2003 Jan;43(1):2-15
references.pmid: 12614627
references.citation: Gen Comp Endocrinol. 2013 Jun 1;186:41-9
references.pmid: 23458287
references.citation: Eur J Pharmacol. 2008 Apr 7;583(2-3):174-85
references.pmid: 18282566
references.citation: Endocrinol Metab Clin North Am. 1987 Dec;16(4):965-80
references.pmid: 3322822
references.citation: Ann N Y Acad Sci. 2004 Jun;1019:321-5
references.pmid: 15247036
references.citation: Neuroendocrinology. 1997 Jan;65(1):79-90
references.pmid: 9032777
references.citation: Physiol Behav. 2008 Oct 20;95(3):508-14
references.pmid: 18706919
references.citation: Am J Physiol. 1963 Nov;205(5):807-15
references.pmid: 4291060
references.citation: Am J Phys Anthropol. 2011 Feb;144(2):169-76
references.pmid: 20721938