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Chemoreflex Contribution to Adrenocortical Function during Acute Hypoxemia in the Llama Fetus at 0.6 to 0.7 of Gestation*
- Source :
- Endocrinology. 139:2564-2570
- Publication Year :
- 1998
- Publisher :
- The Endocrine Society, 1998.
-
Abstract
- This study tested the hypothesis that the fetal llama, a species adapted to the chronic hypoxia of life at high altitude, demonstrates a potent carotid chemoreflex influence on adrenocortical responses during acute hypoxemia. Plasma ACTH and cortisol concentrations, and mesencephalic and adrenal blood flows were measured during a 1-h period of acute hypoxemia in six intact and four carotid sinus-denervated llama fetuses at 0.6-0.7 of gestation. Fetal PaO2 was reduced from approximately 23 to about 14 mm Hg in both intact and carotid-denervated groups during acute hypoxemia. During hypoxemia, fetal plasma ACTH, adrenal blood flow, and, therefore, delivery of ACTH to the adrenals increased to similar extents in both intact and carotid-denervated fetal llamas. Despite this, the increase in plasma cortisol in hypoxemia in intact fetuses was absent in carotid-denervated fetuses. In addition, the increase in delivery of cortisol to the mesencephalon calculated in intact fetuses during hypoxemia did not occur in the carotid-denervated group. These data suggest that the integrity of the carotid chemoreceptors is indispensable to cortisol release during acute hypoxemia in the llama fetus, even at 0.6-0.7 of gestation.
- Subjects :
- medicine.medical_specialty
Hydrocortisone
Blood Pressure
Gestational Age
Hypoxemia
Midbrain
Hemoglobins
Endocrinology
Adrenocorticotropic Hormone
Mesencephalon
Pregnancy
Internal medicine
Animals
Medicine
Hypoxia
Fetus
business.industry
Altitude
Blood flow
Carbon Dioxide
Heart Rate, Fetal
Hydrogen-Ion Concentration
Effects of high altitude on humans
Fetal Blood
medicine.disease
Chemoreceptor Cells
respiratory tract diseases
Oxygen
Carotid Arteries
embryonic structures
Adrenal Cortex
Gestation
Female
medicine.symptom
business
Camelids, New World
circulatory and respiratory physiology
medicine.drug
Subjects
Details
- ISSN :
- 19457170 and 00137227
- Volume :
- 139
- Database :
- OpenAIRE
- Journal :
- Endocrinology
- Accession number :
- edsair.doi.dedup.....b6d1e3c65eec6c01a2df6e1717846150