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ACTH secretion is primarily controlled by hypothalamic secretion of corticotropin releasing factor (CRF) into pituitary portal blood. However arginine vasopressin (AVP) and oxytocin (OT) can modulate the actions of CRF and at times may be important mediators of stress-induced ACTH secretion. The relative contributions of CRF, AVP, and OT to the control of(More)
Hypophysial protal blood was collected from pentobarbital anesthetized male rats, and the content of corticotropin releasing factor-like immunoreactivity (CRF-LI) was measured using an RIA developed for synthetic ovine CRF. The concentration of CRF-LI in portal plasma was 104.9 +/- 9.7 pM. This concentration is in the range which has been shown to stimulate(More)
Oxytocin (OT), vasopressin (AVP), and corticotropin (ACTH) levels were measured in peripheral plasma of male rats subjected to one of three models of stress: restraint, cold, or ether. ACTH secretion was increased in all three groups compared to unstressed controls. OT secretion was increased in rats subjected to restraint or ether but not cold. AVP(More)
To investigate the mechanism by which ACTH secretion is inhibited during hypothermia, hypophysial portal blood was collected from euthermic and hypothermic rats, and the concentrations of corticotropin-releasing factor (CRF), vasopressin (AVP), and oxytocin (OT) were measured by RIA. Whereas CRF levels in portal plasma were not different in the two groups,(More)
The relative role of corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) in mediating serotonin-induced ACTH secretion was studied using the serotonin reuptake inhibitor fluoxetine. Fluoxetine caused a significant increase in ACTH and AVP concentrations in peripheral plasma as well as a significant increase in CRF and AVP concentrations in(More)
The release of oxytocin (OT) into pituitary portal blood during the estrous cycle was studied in female rats under Althesin anesthesia. On each afternoon of the 4-day estrous cycle, animals were anesthetized with Althesin, and pituitary portal blood samples were collected. The concentration of OT in portal plasma collected between 14.00 and 16.00 h of(More)
The effects of CRF(41), oxytocin (OT), and arginine vasopressin (AVP) on ACTH secretion were studied alone and in combination in an in vitro system of superfused rat hemipituitaries. CRF(41) (10(-9)M) and AVP (10(-8)M) alone produced a significant increase in ACTH secretion while OT (10(-8)M) alone had no effect. However the same concentration of OT(More)
Pituitary portal blood was collected from urethane-anesthetized rats and examined for the presence of neuropeptide Y (NPY) using high-performance liquid chromatography and radioimmunoassay. Other rats were perfused with fixative, and coronal sections through the hypothalamus and median eminence were processed for immunohistochemical localization of NPY.(More)
In order to study the interaction between vasopressin (VP) and hypothalamic corticotropin releasing factor (CRF) on the release of ACTH, VP and CRF were administered separately and in combination to normal cycling women. The combined hormones raised plasma ACTH levels higher than the sum of the separate responses and 5 times more than CRF alone. This study(More)