Relation of glucocorticosteroids and testosterone to the annual cycle of free-living degus in semiarid Central Chile

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dc.contributor.authorKenagy, GJ
dc.contributor.authorPlace, NJ
dc.contributor.authorVeloso, C
dc.date.accessioned2025-01-21T01:31:57Z
dc.date.available2025-01-21T01:31:57Z
dc.date.issued1999
dc.description.abstractWe investigated seasonal patterns of plasma glucocorticosteroids (GCs) in both sexes and testosterone (T) in males in relation to the annual cycle in central Chile of a natural population of the degu (Octodon degus), a caviomorph rodent. We wanted to find out which GCs are present in degus, whether their seasonal variation suggests suppressive or synergistic interrelationships with T, and whether seasonal variation in GC levels indicates a relationship with energy mobilization and demands of reproduction. Degus mated in late autumn, and female body mass increased in pregnancy and remained high during lactation and throughout spring. Over the subsequent period of summer drought both sexes declined to a minimal body mass before the next mating season. Cortisol appears to be the principal GC in degus. In fact cortisol levels were so high that the extremely low levels of corticosterone measured were probably largely due to the cross-reactivity of our corticosterone antiserum with cortisol. Titers of cortisol in females exceeded 1000 ng/ml at lactation in the spring of 2 years; cortisol declined greatly following lactation and during the summer and reached its lowest mean level of about 500 ng/ml at mating. Males were more difficult to capture than females and thus our sampling was limited, but male cortisol levels were similar to those of females during the times of year when we measured them. Male T levels remained within a low range all year, but at mating, when mean T was highest (0.16 ng/ml) and when most males had detectable T, degus showed their lowest cortisol levels. The minimal cortisol level of males during mating;represents a possible suppressive effect of T,as described in other mammals. At the time of their spring emergence, 60% of juvenile males had detectable T levels comparable to those of adults, suggesting important organizational effects of T at that time in their maturation. Peak cortisol titers in both sexes were associated with lactation in females, when energy mobilization, production, and body mass were at their greatest. (C) 1999 Academic Press.
dc.fuente.origenWOS
dc.identifier.eissn1095-6840
dc.identifier.issn0016-6480
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/97174
dc.identifier.wosidWOS:000081854200008
dc.issue.numero2
dc.language.isoen
dc.pagina.final243
dc.pagina.inicio236
dc.revistaGeneral and comparative endocrinology
dc.rightsacceso restringido
dc.subjectglucocorticosteroids
dc.subjectcortisol
dc.subjectcorticosterone
dc.subjecttestosterone
dc.subjectbody mass
dc.subjectannual cycle
dc.subjectfield endocrinology
dc.subjectdegu
dc.subjectOctodon degus
dc.subject.ods15 Life on Land
dc.subject.ods13 Climate Action
dc.subject.odspa15 Vida de ecosistemas terrestres
dc.subject.odspa13 Acción por el clima
dc.titleRelation of glucocorticosteroids and testosterone to the annual cycle of free-living degus in semiarid Central Chile
dc.typeartículo
dc.volumen115
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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