Influence of thyrotropin-releasing hormone administration at birth on thermoregulation in lambs delivered by cesarean.
Am J Obstet Gynecol
; 183(5): 1257-62, 2000 Nov.
Article
em En
| MEDLINE
| ID: mdl-11084575
ABSTRACT
OBJECTIVE:
We examined the hypothesis that exogenous stimulation with thyrotropin-releasing hormone immediately before umbilical cord clamping can improve thermoregulation in near-term lambs delivered by cesarean. STUDYDESIGN:
Twin lambs were injected with either saline solution alone (control, n = 12) or thyrotropin-releasing hormone in saline solution (n = 16) and were immediately placed in a warm (30 degrees C; n = 14) or cool (15 degrees C; n = 14) ambient temperature. In vivo measurements of temperature control (colonic temperature, oxygen consumption, and incidence of shivering) were then performed during the first 6 hours after birth, in conjunction with plasma thyroid hormone measurements. Brown adipose tissue was then sampled for measurement of uncoupling protein 1 abundance.RESULTS:
Plasma triiodothyronine concentrations were significantly higher in lambs treated with thyrotropin-releasing hormone than in control lambs between 3 and 6 hours after birth, as were plasma thyroxine concentrations 1 and 5 hours after birth. Delivery temperature had no effect on plasma thyroid hormone concentrations. At 6 hours after birth the abundance of uncoupling protein 1 was higher in lambs treated with thyrotropin-releasing hormone than in control lambs. Lambs treated with thyrotropin-releasing hormone exhibited a lower incidence of shivering than did control lambs between 5 and 6 hours after birth, and an effect of ambient temperature on the incidence of shivering was observed only in the control group. From 3 to 6 hours after birth colonic temperature was significantly higher in cool-delivered lambs treated with thyrotropin-releasing hormone than in the control group. Oxygen consumption was higher in cool-delivered lambs than warm-delivered lambs, but this was not influenced by thyrotropin-releasing hormone. Irrespective of delivery temperature, lambs treated with thyrotropin-releasing hormone possessed more pericardial adipose tissue and hepatic glycogen than did control lambs.CONCLUSION:
Thyrotropin-releasing hormone treatment stimulated thyroid hormone secretion in the neonatal lamb and improved thermoregulation during the first 6 hours after birth in near-term lambs delivered by cesarean under cool conditions.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Regulação da Temperatura Corporal
/
Trabalho de Parto
/
Cesárea
/
Hormônio Liberador de Tireotropina
/
Animais Recém-Nascidos
Limite:
Animals
/
Pregnancy
Idioma:
En
Revista:
Am J Obstet Gynecol
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Reino Unido