The Role of Calcitonin Gene-Related Peptide in the in Vivo Pituitary-Adrenocortical Response to Acute Hypoxemia in the Late-Gestation Sheep Fetus

Abstract

This study tested the hypothesis that calcitonin gene-related peptide (CGRP) has a role in mediating the in vivo fetal adrenal glucocorticoid response to acute stress. The hypothesis was tested by investigating the effects of fetal treatment with a selective CGRP antagonist on plasma ACTH and cortisol responses to acute hypoxemia in the late-gestation sheep fetus. Under anesthesia, six fetuses at 0.8 of gestation were surgically instrumented with vascular catheters. Five days later, fetuses were subjected to 0.5-h hypoxemia during treatment with either iv saline or a CGRP antagonist, in randomized order, on different days. Treatment started 30 min before hypoxemia and ran continuously until the end of the challenge. Arterial blood samples were collected for plasma ACTH and cortisol measurements (RIA) and blood gas monitoring. CGRP antagonism did not alter basal arterial blood gas or endocrine status. During hypoxemia, similar falls in arterial partial pressure of oxygen occurred in all fetuses. During saline infusion, acute hypoxemia induced significant increases in fetal ACTH and cortisol concentrations. During CGRP antagonism, the pituitary-adrenal responses were markedly attenuated. Correlation of paired plasma ACTH and cortisol values from all individual fetuses during normoxia and hypoxemia showed positive linear relationships; however, neither the slope nor the intercept of the peptide-steroid relationship was affected by CGRP antagonism. These data support the hypothesis that CGRP is involved in the in vivo regulation of fetal adrenocortical steroidogenesis during acute hypoxemia. In addition, the data reveal that CGRP may have a role in the control of other components of the hypothalamo-pituitary-adrenal axis during stimulated conditions in fetal life.

Isolating the direct effects of adverse developmental conditions on in vivo cardiovascular function at adulthood: the avian model

“…Blood samples can also be taken during basal and stimulated conditions for subsequent measurement of endocrine responses to challenges, for instance changes in circulating hormones such as catecholamines, adrenocorticotrophic hormone and cortisol, to address changes in the stress axis. [30][31][32] The avian model could also be used to perform glucose or insulin tolerance tests to determine metabolic function. 33 Developmental programming of disease is a fast-moving field, and there is much interest in determining the effects of common adverse conditions during development such as maternal obesity, 34 exposure to stress 35 or chronic fetal hypoxia 36 on cardiovascular function in adult offspring.…”

Research Progress on Anti-Epileptic Mechanism of Acorus Tatarinowii Schott

“…Calcitonin gene relatedpeptide (CGRP) is a vasodilator substance, which is mainly distributed in the central nervous system and cardiovascular system. CGRP can participate in the regulation of the hypothalamus-pituitary-adrenal axis during acute hypoxia, exert its vasodilating activity, and reduce the hypoxic-ischemic damage of tissues [24]. In the early stage of epilepsy, the decrease of CGRP level may be involved in the brain injury caused by epilepsy [25].…”