TIME OF DAY OF BIRTH AND ABSENCE OF ENDOCRINE AND UTERINE CONTRACTILE ACTIVITY RHYTHMS IN SHEEP

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dc.contributor.authorAPOSTOLAKIS, EM
dc.contributor.authorRICE, KE
dc.contributor.authorLONGO, LD
dc.contributor.authorSERONFERRE, M
dc.contributor.authorYELLON, SM
dc.date.accessioned2025-01-23T19:21:49Z
dc.date.available2025-01-23T19:21:49Z
dc.date.issued1993
dc.description.abstractTo determine whether 24-h rhythms characterize hormone secretion and uterine activity in the pregnant sheep, blood samples were drawn every 1-4 h for 48 h from ewes and fetuses from day 120 of gestation to term. Repetitive 24-h rhythms were absent for cortisol, progesterone, and prolactin in maternal and fetal circulation and for hourly mean uterine contraction rate and amplitude. To test whether photoperiod or pineal melatonin contributes to the absence of rhythms, pineal-intact and pinealectomized ewes and their fetuses were studied in reverse photoperiod. Again, there was little evidence to suggest 24-h endocrine rhythms except for prolactin in two fetuses by cosinor analyses. Prolactin concentrations were increased in pinealectomized ewes and their fetuses. In the apparent absence of rhythms, 20 of 21 pineal-intact ewes gave birth at night; however, 6 out of 7 pinealectomized ewes gave birth during the day. Thus photoperiod and the maternal pineal gland profoundly influenced the time of day of birth in the absence of circadian endocrine or uterine activity rhythms.
dc.fuente.origenWOS
dc.identifier.issn0002-9513
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/98881
dc.identifier.wosidWOS:A1993KZ60300048
dc.issue.numero4
dc.language.isoen
dc.pagina.finalE540
dc.pagina.inicioE534
dc.revistaAmerican journal of physiology
dc.rightsacceso restringido
dc.subjectCIRCADIAN RHYTHMS
dc.subjectFETAL ENDOCRINE RHYTHMS
dc.subject.ods05 Gender Equality
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa05 Igualdad de género
dc.subject.odspa03 Salud y bienestar
dc.titleTIME OF DAY OF BIRTH AND ABSENCE OF ENDOCRINE AND UTERINE CONTRACTILE ACTIVITY RHYTHMS IN SHEEP
dc.typeartículo
dc.volumen264
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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