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Abstract
PURPOSE OF REVIEW Diabetes and depression are each public health concerns. They frequently co-occur, compounding complications of each disease. This review provides recent information regarding the mechanisms of association between the disorders and the availability and effectiveness of interventions for youth with diabetes who are depressed. Implications for primary care physicians are considered, particularly in relation to recognition of depression, and also to preventive strategies that increase the patient's self-efficacy (evidence-based confidence in his/her ability to manage diabetes) and serve as protective factors in the development of depression. RECENT FINDINGS Depressive symptoms are strongly associated with diabetes complications. To date, no studies have tested effectiveness of interventions with depressed youth with diabetes. Clinical trials with adults have shown the effectiveness of pharmacotherapy, but those with more complications show the least improvement, and health gains do not persist. In the absence of other data, these findings suggest that it would be prudent to identify and treat comorbid depression in children with diabetes early in the course of their illness, before medical complications develop. SUMMARY Primary care physicians are in an important position to recognize early signs of depression in youth with diabetes and refer them for treatment. Furthermore, the literature provides numerous strategies that can be employed by primary care doctors that may enhance diabetes management as well as protect against depression.
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Affiliation(s)
- Sunita M Stewart
- Department of Psychiatry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
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Chan O, Inouye K, Akirav EM, Park E, Riddell MC, Matthews SG, Vranic M. Hyperglycemia does not increase basal hypothalamo-pituitary-adrenal activity in diabetes but it does impair the HPA response to insulin-induced hypoglycemia. Am J Physiol Regul Integr Comp Physiol 2005; 289:R235-46. [PMID: 15774766 DOI: 10.1152/ajpregu.00674.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recently, we established that hypothalamo-pituitary-adrenal (HPA) and counterregulatory responses to insulin-induced hypoglycemia were impaired in uncontrolled streptozotocin (STZ)-diabetic (65 mg/kg) rats and insulin treatment restored most of these responses. In the current study, we used phloridzin to determine whether the restoration of blood glucose alone was sufficient to normalize HPA function in diabetes. Normal, diabetic, insulin-treated, and phloridzin-treated diabetic rats were either killed after 8 days or subjected to a hypoglycemic (40 mg/dl) glucose clamp. Basal: Elevated basal ACTH and corticosterone in STZ rats were normalized with insulin but not phloridzin. Increases in hypothalamic corticotrophin-releasing hormone (CRH) and inhibitory hippocampal mineralocorticoid receptor (MR) mRNA with STZ diabetes were not restored with either insulin or phloridzin treatments. Hypoglycemia: In response to hypoglycemia, rises in plasma ACTH and corticosterone were significantly lower in diabetic rats compared with controls. Insulin and phloridzin restored both ACTH and corticosterone responses in diabetic animals. Hypothalamic CRH mRNA and pituitary pro-opiomelanocortin mRNA expression increased following 2 h of hypoglycemia in normal, insulin-treated, and phloridzin-treated diabetic rats but not in untreated diabetic rats. Arginine vasopressin mRNA was unaltered by hypoglycemia in all groups. Interestingly, hypoglycemia decreased hippocampal MR mRNA in control, insulin-, and phloridzin-treated diabetic rats but not uncontrolled diabetic rats, whereas glucocorticoid receptor mRNA was not altered by hypoglycemia. In conclusion, despite elevated basal HPA activity, HPA responses to hypoglycemia were markedly reduced in uncontrolled diabetes. We speculate that defects in the CRH response may be related to a defective MR response. It is intriguing that phloridzin did not restore basal HPA activity but it restored the HPA response to hypoglycemia, suggesting that defects in basal HPA function in diabetes are due to insulin deficiency, but impaired responsiveness to hypoglycemia appears to stem from chronic hyperglycemia.
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Affiliation(s)
- Owen Chan
- Department of Physiology, 1 King's College Circle, Medical Sciences Bldg. Rm. 3358, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Inouye KE, Chan O, Yue JTY, Matthews SG, Vranic M. Effects of diabetes and recurrent hypoglycemia on the regulation of the sympathoadrenal system and hypothalamo-pituitary-adrenal axis. Am J Physiol Endocrinol Metab 2005; 288:E422-9. [PMID: 15494609 DOI: 10.1152/ajpendo.00389.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epinephrine, norepinephrine, and corticosterone responses to hypoglycemia are impaired in diabetic rats. Recurrent hypoglycemia further diminishes epinephrine responses. This study examined the sympathoadrenal system and hypothalamo-pituitary-adrenal axis for molecular adaptations underlying these defects. Groups were normal (N) and diabetic (D) rats and diabetic rats exposed to 4 days of 2 episodes/day of hyperinsulinemic hypoglycemia (D-hypo) or hyperinsulinemic hyperglycemia (D-hyper). D-hypo and D-hyper rats differentiated effects of hypoglycemia and hyperinsulinemia. Adrenal tyrosine hydroxylase (TH) mRNA was reduced (P < 0.05 vs. N) 25% in all diabetic groups. Remarkably, mRNA for phenylethanolamine N-methyltransferase (PNMT), which converts norepinephrine to epinephrine, was reduced (P < 0.05 vs. all) 40% only in D-hypo rats. Paradoxically, dopamine beta-hydroxylase mRNA was elevated (P < 0.05 vs. D, D-hyper) in D-hypo rats. Hippocampal mineralocorticoid receptor (MR) mRNA was increased (P < 0.05 vs. N) in all diabetic groups. Hippocampal glucocorticoid receptor (GR), hypothalamic paraventricular nucleus (PVN) GR and corticotropin-releasing hormone (CRH), and pituitary GR and proopiomelanocortin (POMC) mRNA levels did not differ. We conclude that blunted corticosterone responses to hypoglycemia in diabetic rats are not due to altered basal expression of GR, CRH, and POMC in the hippocampus, PVN, and pituitary. The corticosterone defect also does not appear to be due to increased hippocampal MR, since we have reported normalized corticosterone responses in D-hypo and D-hyper rats. Furthermore, impaired epinephrine counterregulation in diabetes is associated with reduced adrenal TH mRNA, whereas the additional epinephrine defect after recurrent hypoglycemia is associated with decreases in both TH and PNMT mRNA.
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Affiliation(s)
- Karen E Inouye
- Department of Physiology, University of Toronto, Medical Sciences Bldg., Rm. 3358, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
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Zelena D, Barna I, Mlynarik M, Gupta OP, Jezova D, Makara GB. Stress symptoms induced by repeated morphine withdrawal in comparison to other chronic stress models in mice. Neuroendocrinology 2005; 81:205-15. [PMID: 16020930 DOI: 10.1159/000087034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Accepted: 04/28/2005] [Indexed: 11/19/2022]
Abstract
The present study was aimed at evaluating chronic stress models in mice with special attention to morphine treatment. We hypothesized that repeated periods of drug withdrawal induce chronic stress. To verify this hypothesis, mice were made dependent on morphine and then subjected to several types of repeated withdrawal. Body weight reduction, thymus involution, adrenal gland enlargement and activation of the hypothalamo-pituitary-adrenal axis were used as signs of chronic stress. The changes were compared to those induced by 'laboratory' models of chronic stress (2 weeks of repeated restraint or rat exposure) and to a disease model of streptozotocin-induced diabetes mellitus (STZ-DM). Mice were made dependent using increasing doses of morphine three times a day for 3 days (10-20-40 mg/kg s.c.). Thereafter, withdrawal was induced either spontaneously (morphine 40 mg/kg injected at 24- or 72-hour time intervals for 2 weeks) or repeatedly precipitated by naloxone (10 mg/kg s.c.) injected daily 3 h after morphine. The results show that repeated periods of spontaneous drug withdrawal (24 or 72 h) in morphine-dependent mice represent a mild stress load. Repeated withdrawal precipitated by naloxone induced clear chronic stress-like changes. Changes observed in the naloxone-precipitated withdrawal model were even more pronounced than those found in laboratory models, namely repeated restraint or exposure to the rat. The most severe chronic stress state developed in mice during untreated STZ-DM. Thus, naloxone-precipitated withdrawal in mice seems to be an appropriate model of chronic stress.
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Affiliation(s)
- Dóra Zelena
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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55
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Psychological and physiological stressors. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0921-0709(05)80041-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Kaye JM, Corrall RJ, Lightman SL. A new test for autonomic cardiovascular and neuroendocrine responses in diabetes mellitus: evidence for early vagal dysfunction. Diabetologia 2005; 48:180-6. [PMID: 15624095 DOI: 10.1007/s00125-004-1615-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 09/23/2004] [Indexed: 11/28/2022]
Abstract
AIMS/HYPOTHESIS Diabetic autonomic neuropathy affects many physiological systems, producing a variety of important clinical manifestations. It is associated with high morbidity and mortality, particularly during times of stress. This is thought to be due to an increased risk of cardiac arrhythmias, although the exact mechanisms involved have yet to be fully elucidated. The aim of the present study was to investigate the endocrine, cardiac autonomic and psychological responses of diabetic patients with and without autonomic neuropathy to a single breath of 35% CO(2). METHODS The 35% CO(2) challenge was performed in 20 male diabetic subjects, 11 of whom had autonomic neuropathy. RESULTS Baseline and stimulated cortisol, prolactin, systolic blood pressure and emotional arousal were similar in the two groups. However, subjects with autonomic neuropathy failed to demonstrate the expected CO(2)-induced bradycardia seen in the non-neuropathic patients (p<0.0001). CONCLUSIONS/INTERPRETATION The CO(2) challenge can be safely and easily administered to produce hypothalamic-pituitary-adrenal axis and cardiac autonomic activation, as well as emotional arousal. The test clearly distinguishes between subjects with and without cardiac autonomic neuropathy and could be an important adjunct to the methods currently available for the investigation and diagnosis of diabetic autonomic neuropathy.
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Affiliation(s)
- J M Kaye
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK.
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Peters A, Schweiger U, Pellerin L, Hubold C, Oltmanns KM, Conrad M, Schultes B, Born J, Fehm HL. The selfish brain: competition for energy resources. Neurosci Biobehav Rev 2004; 28:143-80. [PMID: 15172762 DOI: 10.1016/j.neubiorev.2004.03.002] [Citation(s) in RCA: 279] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Revised: 03/12/2004] [Accepted: 03/17/2004] [Indexed: 01/08/2023]
Abstract
The brain occupies a special hierarchical position in the organism. It is separated from the general circulation by the blood-brain barrier, has high energy consumption and a low energy storage capacity, uses only specific substrates, and it can record information from the peripheral organs and control them. Here we present a new paradigm for the regulation of energy supply within the organism. The brain gives priority to regulating its own adenosine triphosphate (ATP) concentration. In that postulate, the peripheral energy supply is only of secondary importance. The brain has two possibilities to ensure its energy supply: allocation or intake of nutrients. The term 'allocation' refers to the allocation of energy resources between the brain and the periphery. Neocortex and the limbic-hypothalamus-pituitary-adrenal (LHPA) system control the allocation and intake. In order to keep the energy concentrations constant, the following mechanisms are available to the brain: (1) high and low-affinity ATP-sensitive potassium channels measure the ATP concentration in neurons of the neocortex and generate a 'glutamate command' signal. This signal affects the brain ATP concentration by locally (via astrocytes) stimulating glucose uptake across the blood-brain barrier and by systemically (via the LHPA system) inhibiting glucose uptake into the muscular and adipose tissue. (2) High-affinity mineralocorticoid and low-affinity glucocorticoid receptors determine the state of balance, i.e. the setpoint, of the LHPA system. This setpoint can permanently and pathologically be displaced by extreme stress situations (chronic metabolic and psychological stress, traumatization, etc.), by starvation, exercise, infectious diseases, hormones, drugs, substances of abuse, or chemicals disrupting the endocrine system. Disorders in the 'energy on demand' process or the LHPA-system can influence the allocation of energy and in so doing alter the body mass of the organism. In summary, the presented model includes a newly discovered 'principle of balance' of how pairs of high and low-affinity receptors can originate setpoints in biological systems. In this 'Selfish Brain Theory', the neocortex and limbic system play a central role in the pathogenesis of diseases such as anorexia nervosa and obesity.
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Affiliation(s)
- A Peters
- Department of Internal Medicine, University of Luebeck, Ratzeburger Allee 160, D-23538 Germany.
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Matsumoto T, Wakabayashi K, Kobayashi T, Kamata K. Diabetes-related changes in cAMP-dependent protein kinase activity and decrease in relaxation response in rat mesenteric artery. Am J Physiol Heart Circ Physiol 2004; 287:H1064-71. [PMID: 15130892 DOI: 10.1152/ajpheart.00069.2004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using superior mesenteric artery rings isolated from age-matched controls and streptozotocin (STZ)-induced diabetic rats, we recently demonstrated that EDHF-type relaxation is impaired in STZ-induced diabetic rats, possibly due to a reduced action of cAMP via increased phosphodiesterase (PDE) activity (Matsumoto T, Kobayashi T, and Kamata K. Am J Physiol Heart Circ Physiol 285: H283-H291, 2003). Here, we investigated the activity and expression of cAMP-dependent protein kinase (PKA), an enzyme that is produced by a pleiotropic and plays key roles in the transduction of many external signals through the cAMP second messenger pathway and in cAMP-mediated vasorelaxation. The relaxation induced by cilostamide, a selective PDE3 inhibitor, was significantly weaker in superior mesenteric artery rings from STZ-induced diabetic rats than in those from age-matched controls. The relaxation responses to 8-bromo-cAMP (8Br-cAMP) and N6,O2-dibutyryl-adenosine-cAMP (db-cAMP), a cell-permeant cAMP analog, were also impaired in the STZ diabetic group. PKA activity in the db-cAMP-treated mesenteric artery was significantly lower in the STZ diabetic group. The expression levels of the mRNA and protein for PKA catalytic subunit Cat-alpha were significantly decreased in the STZ diabetic group, but those for PKA regulatory subunit isoform RII-beta were increased. We conclude that the abnormal vascular relaxation responsiveness seen in STZ-induced diabetic rats may be attributable not only to increased PDE activity but also to decreased PKA activity. Possibly, the decreased PKA activity may result from an imbalance between PKA catalytic and regulatory subunit expressions.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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Abstract
Energy balance is maintained via a homeostatic system involving both the brain and the periphery. A key component of this system is the hypothalamus. Over the past two decades, major advances have been made in identifying an increasing number of peptides within the hypothalamus that contribute to the process of energy homeostasis. Under stable conditions, equilibrium exists between anabolic peptides that stimulate feeding behavior, as well as decrease energy expenditure and lipid utilization in favor of fat storage, and catabolic peptides that attenuate food intake, while stimulating sympathetic nervous system (SNS) activity and restricting fat deposition by increasing lipid metabolism. The equilibrium between these neuropeptides is dynamic in nature. It shifts across the day-night cycle and from day to day and also in response to dietary challenges as well as peripheral energy stores. These shifts occur in close relation to circulating levels of the hormones, leptin, insulin, ghrelin and corticosterone, and also the nutrients, glucose and lipids. These circulating factors together with neural processes are primary signals relaying information regarding the availability of fuels needed for current cellular demand, in addition to the level of stored fuels needed for long-term use. Together, these signals have profound impact on the expression and production of neuropeptides that, in turn, initiate the appropriate anabolic or catabolic responses for restoring equilibrium. In this review, we summarize the evidence obtained on nine peptides in the hypothalamus that have emerged as key players in this process. Data from behavioral, physiological, pharmacological and genetic studies are described and consolidated in an attempt to formulate a clear statement on the underlying function of each of these peptides and also on how they work together to create and maintain energy homeostasis.
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Affiliation(s)
- Sarah F Leibowitz
- Laboratory of Behavioral Neurobiology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
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Torsoni MA, Carvalheira JB, Pereira-Da-Silva M, de Carvalho-Filho MA, Saad MJA, Velloso LA. Molecular and functional resistance to insulin in hypothalamus of rats exposed to cold. Am J Physiol Endocrinol Metab 2003; 285:E216-23. [PMID: 12644444 DOI: 10.1152/ajpendo.00031.2003] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Insulin and leptin act in the hypothalamus, providing robust anorexigenic signals. The exposure of homeothermic animals to a cold environment leads to increased feeding, accompanied by sustained low levels of insulin and leptin. In the present study, the initial and intermediate steps of the insulin-signaling cascade were evaluated in the hypothalamus of cold-exposed Wistar rats. By immunohistochemistry, most insulin receptor (IR) and insulin receptor substrate-2 (IRS-2) immunoreactivity localized to the arcuate nucleus. Basal levels of tyrosine phosphorylation of IR and IRS-2 were increased in cold-exposed rats compared with rats maintained at room temperature. However, after an acute, peripheral infusion of exogenous insulin, significantly lower increases of IR and IRS-2 tyrosine phosphorylation were detected in the hypothalamus of cold-exposed rats. Insulin-induced association of p85/phosphatidylinositol 3-kinase with IRS-2, Ser473 phosphorylation of Akt, and tyrosine phosphorylation of ERK was significantly reduced in the hypothalamus of cold-exposed rats. To test the hypothesis of functional impairment of insulin signaling in the hypothalamus, intracerebroventricularly cannulated rats were acutely treated with insulin, and food ingestion was measured over a period of 12 h. Cold-exposed animals presented a significantly lower insulin-induced reduction in food consumption compared with animals maintained at room temperature. Hence, the present studies reveal that animals exposed to cold are resistant, both at the molecular and the functional level, to the actions of insulin in the hypothalamus.
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Affiliation(s)
- Márcio A Torsoni
- Department of Internal Medicine, State University of Campinas, Brazil
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Current literature in diabetes. Diabetes Metab Res Rev 2002; 18:419-26. [PMID: 12397584 DOI: 10.1002/dmrr.247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Chan O, Inouye K, Vranic M, Matthews SG. Hyperactivation of the hypothalamo-pituitary-adrenocortical axis in streptozotocin-diabetes is associated with reduced stress responsiveness and decreased pituitary and adrenal sensitivity. Endocrinology 2002; 143:1761-8. [PMID: 11956158 DOI: 10.1210/endo.143.5.8809] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although increased hypothalamo-pituitary-adrenocortical (HPA) activity has been reported in diabetic patients, the mechanisms underlying hyperactivation are still unclear. We investigated whether alterations in pituitary, adrenal and/or glucocorticoid negative feedback sensitivity in diabetes are responsible for 1) the impaired HPA response to stress and 2) basal hyperactivation of the HPA axis. Normal control, untreated streptozotocin-diabetic and insulin-treated diabetic rats were chronically catheterized. Eight days following surgery, pituitary-adrenal function was monitored throughout the day. Stress responsiveness was evaluated using 20 min of restraint on d 10. Thereafter, the rats were treated with CRH (0.5 microg/kg), ACTH(1-24) (75ng/kg) or dexamethasone (25 microg/kg) iv on d 12, 14, and 16 to evaluate pituitary, adrenal and glucocorticoid feedback sensitivity, respectively. Plasma ACTH and corticosterone (B) concentrations in untreated diabetic rats were significantly higher at 0800 h, but no different at 1300 h or 1800 h. Insulin treatment of diabetic rats normalized ACTH and B concentrations at 0800 h. The pituitary-adrenal response to restraint was greatly diminished in untreated diabetic rats, whereas insulin treatment partially restored this response in diabetic rats. Administration of CRH and ACTH revealed reduced pituitary and adrenal sensitivity in untreated diabetic animals compared with both control and insulin-treated diabetic animals. The dexamethasone suppression test indicated decreased glucocorticoid negative feedback sensitivity in diabetic rats, which was restored with insulin treatment. In conclusion, these studies demonstrate that: 1) impaired stress responsiveness of the diabetic HPA axis involves both decreased pituitary and adrenal sensitivity; and 2) basal hyperactivation of the diabetic HPA axis in the morning is due, in part, to decreased glucocorticoid negative feedback sensitivity.
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Affiliation(s)
- Owen Chan
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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