{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/34190"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/34190","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The effects of induced hypothyroidism on the glucocorticoid stress response in Japanese quail (Coturnix japonica)","abstract":"Many aspects of biological function are affected by hormones, from physiology to behavior, and the synthesis and release of hormones in vertebrates are regulated by the endocrine axes of control. A growing body of research shows that the mechanisms underlying the endocrine axes of control are complex and interconnected, with many hormones having multiple effects, and with many interactions between axes. In this study, I examined the effects of decreased thyroid function on the glucocorticoid stress response in Japanese quail, a potential interaction between the hypothalamic-pituitary thyroid (HPT) and hypothalamic-pituitary adrenal (HPA) axes of control. I used the thyroid inhibitor ammonium perchlorate (AP) for 2 weeks and 5 weeks to induce two states of decreased thyroid function: a thyroid challenged state, in which birds have depleted thyroidal T4 content, but still maintain euthyroid (normal) concentrations of plasma T4, and a hypothyroid state, in which birds have depleted thyroidal T4 content and decreased concentrations of plasma T4. Thyroid function was assessed by measuring plasma T4 concentrations, thyroidal T4 content, and thyroid gland mass. I took blood samples from birds both immediately prior to and immediately following a 30 minute confinement and agitation stressor to evaluate the effects of decreases in thyroid function on basal and stress-induced plasma corticosterone and plasma T4 concentrations. I found two key results: First, although baseline levels of plasma corticosterone were unchanged, the corticosterone stress response was significantly blunted in both the thyroid challenged and hypothyroid birds as compared to controls. This finding suggests that the HPT and HPA axes are functionally connected in birds, and other evidence suggests this connection is likely at the pituitary or hypothalamic level. Second, in hypothyroid birds, plasma T4 concentrations were elevated (into the euthyroid range) in response to the experimental stressor, although no change in plasma T4 was observed in thyroid challenged or control birds. This finding suggests that plasma T4 may have a permissive role in mounting a stress response.","abstract_html":"Many aspects of biological function are affected by hormones, from physiology to behavior, and the synthesis and release of hormones in vertebrates are regulated by the endocrine axes of control. A growing body of research shows that the mechanisms underlying the endocrine axes of control are complex and interconnected, with many hormones having multiple effects, and with many interactions between axes. In this study, I examined the effects of decreased thyroid function on the glucocorticoid stress response in Japanese quail, a potential interaction between the hypothalamic-pituitary thyroid (HPT) and hypothalamic-pituitary adrenal (HPA) axes of control. I used the thyroid inhibitor ammonium perchlorate (AP) for 2 weeks and 5 weeks to induce two states of decreased thyroid function: a thyroid challenged state, in which birds have depleted thyroidal T4 content, but still maintain euthyroid (normal) concentrations of plasma T4, and a hypothyroid state, in which birds have depleted thyroidal T4 content and decreased concentrations of plasma T4. Thyroid function was assessed by measuring plasma T4 concentrations, thyroidal T4 content, and thyroid gland mass. I took blood samples from birds both immediately prior to and immediately following a 30 minute confinement and agitation stressor to evaluate the effects of decreases in thyroid function on basal and stress-induced plasma corticosterone and plasma T4 concentrations. I found two key results: First, although baseline levels of plasma corticosterone were unchanged, the corticosterone stress response was significantly blunted in both the thyroid challenged and hypothyroid birds as compared to controls. This finding suggests that the HPT and HPA axes are functionally connected in birds, and other evidence suggests this connection is likely at the pituitary or hypothalamic level. Second, in hypothyroid birds, plasma T4 concentrations were elevated (into the euthyroid range) in response to the experimental stressor, although no change in plasma T4 was observed in thyroid challenged or control birds. This finding suggests that plasma T4 may have a permissive role in mounting a stress response.","abstract_has_math":false,"creators":["Weigel, Eric Roan"],"institution":"Virginia Tech","degree_name":"Master of Science in Life Sciences","degree_level":"masters","degree_discipline":"Biology","degree_department":"Biology","school":null,"contributors":[],"advisors":[],"committee_chairs":["McNabb, F. M. Anne","Moore, Ignacio T."],"committee_members":["Denbow, D. Michael","Cranford, Jack A."],"year":2007,"date_issued":"2007-06-28","date_published":"2007-06-28","updated_at":"2026-07-22T22:20:05Z","subjects":["stress","hypothyroidism","perchlorate","Japanese quail","glucocorticoid"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-07262007-153448"],"render_values":[{"text":"etd-07262007-153448","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/34190","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["McNabb, F. M. Anne","Moore, Ignacio T."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Denbow, D. Michael","Cranford, Jack A."]},{"key":"dc:contributor.department","label":"Department","values":["Biology"]},{"key":"dc:creator","label":"Author","values":["Weigel, Eric Roan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:42:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:42:02Z","2010-10-27"]},{"key":"dc:date.issued","label":"Date","values":["2007-06-28"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Life Sciences"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["stress","hypothyroidism","perchlorate","Japanese quail","glucocorticoid"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-07262007-153448"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/34190"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Many aspects of biological function are affected by hormones, from physiology to behavior, and the synthesis and release of hormones in vertebrates are regulated by the endocrine axes of control. A growing body of research shows that the mechanisms underlying the endocrine axes of control are complex and interconnected, with many hormones having multiple effects, and with many interactions between axes. In this study, I examined the effects of decreased thyroid function on the glucocorticoid stress response in Japanese quail, a potential interaction between the hypothalamic-pituitary thyroid (HPT) and hypothalamic-pituitary adrenal (HPA) axes of control. I used the thyroid inhibitor ammonium perchlorate (AP) for 2 weeks and 5 weeks to induce two states of decreased thyroid function: a thyroid challenged state, in which birds have depleted thyroidal T4 content, but still maintain euthyroid (normal) concentrations of plasma T4, and a hypothyroid state, in which birds have depleted thyroidal T4 content and decreased concentrations of plasma T4. Thyroid function was assessed by measuring plasma T4 concentrations, thyroidal T4 content, and thyroid gland mass. I took blood samples from birds both immediately prior to and immediately following a 30 minute confinement and agitation stressor to evaluate the effects of decreases in thyroid function on basal and stress-induced plasma corticosterone and plasma T4 concentrations. I found two key results: First, although baseline levels of plasma corticosterone were unchanged, the corticosterone stress response was significantly blunted in both the thyroid challenged and hypothyroid birds as compared to controls. This finding suggests that the HPT and HPA axes are functionally connected in birds, and other evidence suggests this connection is likely at the pituitary or hypothalamic level. Second, in hypothyroid birds, plasma T4 concentrations were elevated (into the euthyroid range) in response to the experimental stressor, although no change in plasma T4 was observed in thyroid challenged or control birds. This finding suggests that plasma T4 may have a permissive role in mounting a stress response."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science in Life Sciences"]},{"key":"dc:title","label":"Title","values":["The effects of induced hypothyroidism on the glucocorticoid stress response in Japanese quail (Coturnix japonica)"]}]}],"canonical_facts":{"dc:contributor.committeechair":["McNabb, F. M. Anne","Moore, Ignacio T."],"dc:contributor.committeemember":["Denbow, D. Michael","Cranford, Jack A."],"dc:contributor.department":["Biology"],"dc:creator":["Weigel, Eric Roan"],"dc:date.accessioned":["2014-03-14T20:42:02Z"],"dc:date.available":["2014-03-14T20:42:02Z","2010-10-27"],"dc:date.issued":["2007-06-28"],"dc:description.abstract":["Many aspects of biological function are affected by hormones, from physiology to behavior, and the synthesis and release of hormones in vertebrates are regulated by the endocrine axes of control. A growing body of research shows that the mechanisms underlying the endocrine axes of control are complex and interconnected, with many hormones having multiple effects, and with many interactions between axes. In this study, I examined the effects of decreased thyroid function on the glucocorticoid stress response in Japanese quail, a potential interaction between the hypothalamic-pituitary thyroid (HPT) and hypothalamic-pituitary adrenal (HPA) axes of control. I used the thyroid inhibitor ammonium perchlorate (AP) for 2 weeks and 5 weeks to induce two states of decreased thyroid function: a thyroid challenged state, in which birds have depleted thyroidal T4 content, but still maintain euthyroid (normal) concentrations of plasma T4, and a hypothyroid state, in which birds have depleted thyroidal T4 content and decreased concentrations of plasma T4. Thyroid function was assessed by measuring plasma T4 concentrations, thyroidal T4 content, and thyroid gland mass. I took blood samples from birds both immediately prior to and immediately following a 30 minute confinement and agitation stressor to evaluate the effects of decreases in thyroid function on basal and stress-induced plasma corticosterone and plasma T4 concentrations. I found two key results: First, although baseline levels of plasma corticosterone were unchanged, the corticosterone stress response was significantly blunted in both the thyroid challenged and hypothyroid birds as compared to controls. This finding suggests that the HPT and HPA axes are functionally connected in birds, and other evidence suggests this connection is likely at the pituitary or hypothalamic level. Second, in hypothyroid birds, plasma T4 concentrations were elevated (into the euthyroid range) in response to the experimental stressor, although no change in plasma T4 was observed in thyroid challenged or control birds. This finding suggests that plasma T4 may have a permissive role in mounting a stress response."],"dc:description.degree":["Master of Science in Life Sciences"],"dc:identifier.other":["etd-07262007-153448"],"dc:identifier.uri":["http://hdl.handle.net/10919/34190"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["stress","hypothyroidism","perchlorate","Japanese quail","glucocorticoid"],"dc:title":["The effects of induced hypothyroidism on the glucocorticoid stress response in Japanese quail (Coturnix japonica)"],"dc:type":["Thesis"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science in Life Sciences"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:05Z"}