This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Riquelme, R. A. Articles by Giussani, D. A. Search for Related Content PubMed PubMed Citation Articles by Riquelme, R. A. Articles by Giussani, D. A.

Chemoreflex Contribution to Adrenocortical Function during Acute Hypoxemia in the Llama Fetus at 0.6 to 0.7 of Gestation¹

Programa de Patología, Campus Oriente, Instituto de Ciencias Biomédicas, Facultad de Medicina (R.A.R., J.A.L., E.M.S.), International Center for Andean Research, Universidad de Chile, Santiago, Chile; The Physiological Laboratory, University of Cambridge (D.A.G.), Cambridge, United Kingdom CB2 3EG; and the Department of Obstetrics and Gynecology, University College London (H.H.G.M., M.A.H.), London, United Kingdom WC1E 6HX

Address all correspondence and requests for reprints to: Raquel A. Riquelme, Programa de Patología, Campus Oriente, Instituto de Ciencias Biomédicas, Facultad de Medicina, International Center for Andean Research, Universidad de Chile, Casilla 16038, Santiago 9, Chile.

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.

This article has been cited by other articles:

				A. S. Thakor and D. A. Giussani The Role of Calcitonin Gene-Related Peptide in the in Vivo Pituitary-Adrenocortical Response to Acute Hypoxemia in the Late-Gestation Sheep Fetus Endocrinology, November 1, 2005; 146(11): 4871 - 4877. [Abstract] [Full Text] [PDF]

				T. Imamura, H. Umezaki, K. M. Kaushal, and C. A. Ducsay Long-Term Hypoxia Alters Endocrine and Physiologic Responses to Umbilical Cord Occlusion in the Ovine Fetus Reproductive Sciences, April 1, 2004; 11(3): 131 - 140. [Abstract] [PDF]

				R. A Riquelme, G. Sanchez, L. Liberona, E. M Sanhueza, D. A Giussani, C. E Blanco, M. A Hanson, and A. J Llanos Nitric oxide plays a role in the regulation of adrenal blood flow and adrenocorticomedullary functions in the llama fetus J. Physiol., October 1, 2002; 544(1): 267 - 276. [Abstract] [Full Text] [PDF]

				L. R. Green Programming of Endocrine Mechanisms of Cardiovascular Control and Growth Reproductive Sciences, April 1, 2001; 8(2): 57 - 68. [Abstract] [PDF]

				D A Giussani, R A Riquelme, E M Sanhueza, M A Hanson, C E Blanco, and A J Llanos Adrenergic and vasopressinergic contributions to the cardiovascular response to acute hypoxaemia in the llama fetus J. Physiol., February 15, 1999; 515(1): 233 - 241. [Abstract] [Full Text] [PDF]