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Effects of age on ACTH, corticosterone, glucose, insulin, and mRNA levels during intermittent hypoxia in the neonatal rat. Am J Physiol Regul Integr Comp Physiol 2013 May 01;304(9):R782-9

Date

03/15/2013

Pubmed ID

23485866

DOI

10.1152/ajpregu.00073.2013

Scopus ID

2-s2.0-84878627343   19 Citations

Abstract

Apnea, the temporary cessation of respiratory airflow, is a common cause of intermittent hypoxia (IH) in premature infants. We hypothesized that IH elicits a stress response and alters glucose homeostasis in the neonatal rat. Rat pups were studied on postnatal day (PD) 2, 8, 10, 12, and 14. Pups were exposed to normoxia (control) or six cycles consisting of 30-s exposures to hypoxia (FiO2 = 3%) over a 60-min period. Blood samples were obtained at baseline, after the third cycle (~30 min), and after the sixth cycle (~60 min). Tissue samples were collected following the sixth cycle. Plasma ACTH, corticosterone, glucose, and insulin were analyzed at all ages. Hypothalamic, pituitary, and adrenal mRNA expression was evaluated by quantitative PCR in PD2, PD8, and PD12 pups. Exposure to IH elicited significant increases in plasma ACTH and corticosterone at all ages studied. The largest increase in corticosterone occurred in PD2 pups, despite only a very small increase in plasma ACTH. This ACTH-independent increase in corticosterone in PD2 pups was associated with increases in adrenal Ldlr and Star mRNA expression. Additionally, IH caused hyperglycemia and hyperinsulinemia at all ages. We conclude that IH elicits a significant pituitary-adrenal response and significantly alters glucose homeostasis. Furthermore, the quantitative and qualitative characteristics of these responses depend on developmental age.

Author List

Chintamaneni K, Bruder ED, Raff H

Author

Hershel Raff PhD Professor in the Medicine department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adrenocorticotropic Hormone
Aging
Animals
Animals, Newborn
Blood Glucose
Body Temperature
Corticosterone
Female
Heart Rate
Hypothalamo-Hypophyseal System
Hypoxia
Insulin
Oxygen Consumption
Phosphoproteins
Pituitary-Adrenal System
Pregnancy
RNA
RNA, Messenger
Rats
Rats, Sprague-Dawley
Real-Time Polymerase Chain Reaction
Receptors, LDL
jenkins-FCD Prod-484 8aa07fc50b7f6d102f3dda2f4c7056ff84294d1d