Corticotrophin releasing factor in man and its measurement: a review

The dexamethasone/corticotropin-releasing factor test in men with major depression: role of childhood trauma

BACKGROUND

The dexamethasone/corticotropin-releasing factor (CRF) test is considered to be the most sensitive measure of hypothalamic-pituitary-adrenal (HPA) axis hyperactivity and has been demonstrated to be altered in patients with major depression (MDD). Although childhood trauma is a demonstrated risk factor for MDD and patients with a history of childhood abuse and MDD demonstrate HPA axis hyperactivity, the dexamethasone/CRF test remains unstudied in this population. We determined the impact of childhood trauma on dexamethasone/CRF test results in patients with MDD.

METHODS

Forty-nine healthy men, ages 18-60 years, without mania or psychosis, active substance abuse, or eating disorder and medication-free were recruited into four study groups, including: 1) normal subjects with no childhood abuse history or psychiatric disorder (n = 14); 2) men with childhood abuse histories without current MDD (n = 14); 3) men with childhood abuse histories with current MDD (n = 15); and 4) men with current MDD and no childhood abuse history (n = 6). Plasma adrenocorticotropin (ACTH) and cortisol concentrations were measured in response to dexamethasone/CRF administration.

RESULTS

Men with childhood trauma histories exhibited increases in ACTH and cortisol responses to dexamethasone/CRF compared with non-abused men. In particular, abused men with current MDD showed increased responsiveness compared with control subjects and depressed men without childhood abuse experience. Increased response was associated with the severity, duration, and earlier onset of the abuse. The effects were not explained by concurrent posttraumatic stress disorder.

CONCLUSIONS

Childhood trauma increases HPA axis activity as measured with the dexamethasone/CRF test in adult men with MDD, potentially reflecting environmental risk for developing depression.

Stress sensitivity in metastatic breast cancer: analysis of hypothalamic-pituitary-adrenal axis function

The normal diurnal cortisol cycle has a peak in the morning, decreasing rapidly over the day, with low levels during the night, then rising rapidly again to the morning peak. A pattern of flatter daytime slopes has been associated with more rapid cancer progression in both animals and humans. We studied the relationship between the daytime slopes and other daytime cortisol responses to both pharmacological and psychosocial challenges of hypothalamic-pituitary-adrenal (HPA) axis function as well as DHEA in a sample of 99 women with metastatic breast cancer, in hopes of elucidating the dysregulatory process. We found that the different components of HPA regulation: the daytime cortisol slope, the rise in cortisol from waking to 30 min later, and cortisol response to various challenges, including dexamethasone (DEX) suppression, corticotrophin releasing factor (CRF) activation, and the Trier Social Stress Task, were at best modestly associated. Escape from suppression stimulated by 1mg of DEX administered the night before was moderately but significantly associated with flatter daytime cortisol slopes (r=0.28 to .30 at different times of the post DEX administration day, all p<.01). Daytime cortisol slopes were also moderately but significant associated with the rise in cortisol from waking to 30 min after awakening (r=.29, p=.004, N=96), but not with waking cortisol level (r=-0.13, p=.19). However, we could not detect any association between daytime cortisol slope and activation of cortisol secretion by either CRF infusion or the Trier Social Stress Task. The CRF activation test (following 1.5mg of DEX to assure that the effect was due to exogenous CRF) produced ACTH levels that were correlated (r=0.66, p<.0001, N=74) with serum cortisol levels, indicating adrenal responsiveness to ACTH stimulation. Daytime cortisol slopes were significantly correlated with the slope of DHEA (r=.21, p=.04, N=95). Our general findings suggest that flatter daytime cortisol slopes among metastatic breast cancer patients may be related to disrupted feedback inhibition rather than hypersensitivity in response to stimulation.

Physiological and emotional response to psychological stressors in psychiatric and psychosomatic disorders

Deviations from emotional and physiological homeostasis in humans occur under episodic, chronic, or traumatic stress experiences. These dysregulations can provoke emotional and physical disturbances that may result in stress-related psychiatric or psychosomatic disorders. This brief review discusses a variety of both naturally occurring and experimental stressors and the complexity of intervening variables on cardiovascular and hormonal dysregulations of the hypothalamic-pituitary-adrenal (HPA) axis. In addition to the type, intensity, and duration of the stressor, subject variables such as dispositional factors (e.g., age and sex), personality traits, and coping styles are considered. Finally, emotional and physiological stress responses to naturally occurring stressors and psychological challenge tests in depressed patients and anxiety disorder patients are presented and discussed. Stressors in humans induce emotional arousal, which leads to physiological activation of the central nervous system, an increase of hormones of the HPA axis, and coping reactions on the psychological and behavioral level. Depending on the type, intensity, and duration of the stressor, on personal and psychosocial resources of the individual, stressful situations may provoke emotional and physical disturbances. These dysfunctions may result in psychosomatic or psychiatric disorders. The following brief review intends to discuss a variety of stressors that have been examined in humans in order to gain insight into the complex relationship between physiological and behavioral stress reactions and the occurrence or maintenance of stress related psychosomatic and psychiatric disorders.

Abuse-related posttraumatic stress disorder and alterations of the hypothalamic-pituitary-adrenal axis in women with chronic pelvic pain

OBJECTIVE

Although numerous organic conditions may cause chronic pelvic pain (CPP), diagnostic laparoscopy reveals a normal pelvis in many patients with CPP. However, psychological studies yield a high frequency of psychopathology and increased prevalences of chronic stress and traumatic life events, ie, sexual and physical abuse, in women with CPP, suggesting a relationship between posttraumatic stress disorder (PTSD) and CPP. As chronic stress and PTSD have been associated with specific alterations of the hypothalamic-pituitary-adrenal (HPA) axis, we explored stress history, psychopathology and HPA axis alterations in women with CPP.

METHOD

We recruited 16 patients with CPP and 14 painfree, infertile controls from a general hospital where diagnostic laparoscopy was performed. Psychological assessment included standardized interviews on clinical symptoms, abuse experiences and major life events as well as psychometric testing for PTSD-like symptoms and depression. Endocrinological evaluation involved determinations of diurnal salivary cortisol levels and hormonal responses to a corticotropin-releasing factor (CRF) stimulation test (100 microg human CRF) and a low-dose dexamethasone suppression test (0.5 mg).

RESULTS

We observed increased prevalences of abuse experiences and PTSD in women with CPP as well as a higher total number of major life events, whereas the mean extent of depression was within the normal range. With respect to endocrine measures, women with CPP demonstrated normal to low diurnal salivary cortisol levels, normal plasma-adrenocorticotropin (ACTH), but reduced salivary cortisol levels in the CRF stimulation test, and an enhanced suppression of salivary cortisol by dexamethasone.

CONCLUSION

Women with CPP demonstrate HPA axis alterations, that partly parallel and partly contrast neuroendocrine correlates of PTSD, but show marked similarity to findings in patients with other stress-related bodily disorders. These findings suggest that a lack of protective properties of cortisol may be of relevance for the development of bodily disorders in chronically stressed or traumatized individuals.

[The necessity for perioperative cortisol substitution. Spontaneous and stimulated ACTH and cortisol secretion during unilateral adrenalectomy for renal cell carcinoma]

Impaired adrenal function during perioperative stress carries the risk of acute cortisol (Cs) deficiency (Addisonian crisis), which may be critical without Cs supplementation. Thus, with evidence of dysfunction of the adrenal glands perioperative substitution is indicated. However, it is unclear whether unilateral adrenalectomy may attenuate the adrenocorticoid response. Glucocorticosteroids are potent agents with several well-known side effects. The purpose of the present study was to evaluate if routine Cs supplementation is justified and necessary in patients undergoing adrenalectomy during nephrectomy for renal-cell cancer.

METHODS

Ten consecutive patients with renal-cell cancer (5 male, 5 female; age 58 +/- 10 years; ASA class I-II) who underwent adrenalectomy with radical nephrectomy were included in this study. None of them had received steroids for at least 5 years prior to the current surgery. Anaesthesia was induced with propofol, fentanyl, and vecuronium and maintained with isoflurane (PetIso: 0.8 +/- 0.3 vol.%) in nitrous oxide (66%) and oxygen. The patients did not receive any Cs treatment perioperatively. Monitoring included heart rate (beats/min), mean arterial pressure (mm Hg), central venous pressure (mm Hg), O2 saturation (%), and body temperature (degrees C, rectal). Plasma analyses included Cs (Cs radioimmunoassay IBL; normal 120-250 ng/ml), adrenocorticotropic hormone (ACTH) (ACTH-II IRMA; normal (10-50 pg/ml), glucose, and electrolytes determined as follows: preoperatively (8 a.m.); 1-6 h (60-min intervals) after surgery; pre-corticotropin-releasing hormone (CRH) (Corticobiss: 2 micrograms/kg i.v.) administration (1st postop. day at 8 a.m. and after 30, 60, 90, and 120 min. The study was completed with plasma analyses on postoperative days 2 and 3 (8 a.m.).

RESULTS

None of the patients showed any clinical signs of plasma parameter of adrenal insufficiency due to the unilateral adrenalectomy. Serum levels (median: 25%/75% percentiles) of Cs (maximum [max.]:253 [217/288] ng/ml) and ACTH (max.:347 ([68/405] pg/ml) were elevated above the normal range postoperatively). After intravenous stimulation with CRH (1st postoperative day), Cs (max.:273 [248/310] ng/ml) and ACTH (max.: 107 ([75/275] pg/ml) were also increased above normal. During postoperative days 2 and 3 (8 a.m.) Cs and ACTH remained in the high-normal range.

CONCLUSIONS

Data from this study indicate that unilateral adrenalectomy was associated with adequate spontaneous Cs secretion by the remaining adrenal gland. Moreover, stimulation with CRH demonstrated adequate reactivity of the pituitary-adrenal axis. None of the patients showed any signs of Cs deficiency by clinical or serum parameters. Therefore, we do not recommend routine Cs supplementation in patients undergoing adrenalectomy during tumor nephrectomy, nevertheless, Cs supplementation remains necessary for patients with primary hypothalamic-pituitary-adrenal dysfunction (Addison's disease) or hyperfunction (Cushing's disease).

High intracerebral levels of CRH result in CRH receptor downregulation in the amygdala and neuroimmune desensitization

Corticotropin-releasing hormone (CRH) acts at the pituitary level to increase ACTH secretion and, within the central nervous system, to stimulate the sympathoadrenomedullary axis and behavioral activity. In addition, the central administration of CRH has been reported to reduce cellular immunity in the periphery. This study investigated the temporal relationship between CRH receptor regulation and the changes in splenic natural killer (NK) cell and pituitary-adrenocortical hormone responses to a single intracisternal (IC) CRH challenge (acute CRH) 24 h after chronic CRH pretreatment (5 nmol/day IC CRH for 4 days). Chronic CRH significantly decreased by 44.2 +/- 7.8% (P < 0.01) the CRH receptor concentration (beta max) in the amygdala. In contrast, the CRH receptor concentration of the anterior pituitary in the chronic CRH group was similar to the pituitary CRH receptor concentration in chronic saline controls. The immunoreactive-CRH concentration of the amygdala measured 24 h after the last IC CRH injection was not different from brain CRH levels in controls receiving chronic saline pretreatment. Consequently, the downregulation of amygdala CRH receptors occurred after transient increases in intracerebral CRH levels and did not result from ex vivo receptor occupancy by residual exogenous CRH sequestrated in brain tissue at the time of the CRH binding assay. Pretreatment with chronic CRH completely abolished the ability of a central CRH injection to suppress splenic NK activity; whereas, pituitary-adrenal responses to a superimposed acute CRH challenge were not significantly altered by chronic CRH pretreatment. These results suggest that the desensitization of the brain processes mediating CRH-induced suppression of splenic NK cytotoxicity is temporally correlated with CRH receptor downregulation in the amygdala but independent of pituitary-adrenal activation. These findings represent the first in vivo demonstration of homologous downregulation of extrahypothalamic CRH receptors and provide further evidence for the role of central CRH in the modulation of immune function.

Isolated adrenocorticotropic hormone deficiency secondary to hypothalamic deficit of corticotropin releasing hormone

A 42-year-old man and a 51-year-old woman with a positive history of weakness and gastrointestinal complaints were shown to have low basal plasma cortisol and ACTH levels, and low daily urinary excretion of free cortisol. An empty sella was found in patient no. 1, while patient no. 2 was hypothyroid. Both patients showed a normal plasma cortisol response to ACTH and an increment in plasma ACTH and lipotropin levels after ovine CRH (oCRH), lysine vasopressin (LVP) and oCRH-LVP stimulation tests. These studies clearly report an isolated idiopathic ACTH deficiency due to a deficit in CRH in two adult subjects.

Safety and side effects of human and ovine corticotropin-releasing hormone administration in man

Synthetic human and ovine corticotropin-releasing hormone (hCRH, oCRH) are commonly used as a diagnostic tool of the hypothalamo-pituitary-adrenal axis. In this paper reports about side effects after various modes of CRH-application are analyzed and compared to our corresponding data of human studies with hCRH and oCRH. Generally, CRH is well tolerated after single administration and interval-application of standard doses, although minor side effects appear sometimes after higher doses (greater than 200 micrograms hCRH, oCRH) of CRH-bolus-injections. Predominantly the cardiovascular system (e.g. tachycardia, hypotension, flushing) is affected; neuropsychological symptoms are only seen sporadically (e.g. dizziness). Long term continuous infusion (several hours) of low CRH-doses (hCRH, oCRH) are well tolerated but side effects appear (see above) when cumulated doses of 200 micrograms-300 micrograms/h are given. Standard doses of hCRH and oCRH are also well tolerated in severely ill patients; it has to be considered that higher doses may provoke marked side effects in persons with neurologic disorders, in subjects with coronary heart disease and in patients with endocrinological disorders of the pituitary-adrenal axis, especially in those subjects in whom the blood-brain-barrier may have been damaged (e.g. head injury, intracranial operation). Single hCRH- and oCRH-bolus-injections in standard doses have a very low rate of complications, "non-standard" doses should provisionally be used only in clinical studies with well designed safety-precautions.

Urinary corticotropin-releasing hormone immunoreactivity is elevated during human pregnancy

Plasma corticotropin-releasing hormone immunoreactivity (CRH IR) rises with gestational age in women. In order to investigate the physiological changes of the hormone in pregnant women's urine, CRH IR was measured by radioimmunoassay in urine collected over a 24-hour period, a blood sample and a subsequent single collection of urine after the 24-hour collection (spot urine). Plasma CRH IR in pregnant subjects, 8682.8 +/- 2063.0 pg CRH IR/ml plasma (mean +/- SEM, n = 25), was significantly higher than that in the non-pregnant controls (7.2 +/- 1.6 pg/ml, n = 5; separate t = 4.21, p = 0.0003, d.f. = 24). Similarly, pregnant women had higher spot urine CRH IR - 54.6 +/- 15.5 pg/mumol creatinine (Cr) versus 5.0 +/- 0.5 pg/mumol Cr (separate t = 3.20, p = 0.0038, d.f. = 24.0) - and 24-hour urine CRH IR - 13.7 +/- 1.2 pg/mumol Cr compared with 7.7 +/- 0.8 pg/mumol Cr (separate t = 4.28, p = 0.003, d.f. = 24.4) than the non-pregnant cohort. The difference between urinary excretion of CRH IR as estimated by 24-hour urine (13.7 +/- 1.2 pg/mumol Cr) and spot urine (54.6 +/- 15.5 pg/mumol Cr) indicated that CRH IR in 24-hour urine may be degraded during storage. The weak associations between plasma and 24-hour urine CRH IR of pregnant women (correlation coefficient r = 0.34, p greater than 0.1), and total 24-hour urine and spot urine CRH IR (r = 0.25, p less than 0.1) further indicate CRH degradation. Plasma and spot urinary CRH IR, however, were strongly correlated (r = 0.80, p = 0.001). The total CRH IR excreted as estimated from the spot urine value (0.5 +/- 0.1 micrograms/day) compared with the total filtered load of CRH IR in the pregnant group (1306.9 +/- 324.6 micrograms/day) showed that 99.97% of the filtered CRH IR was reabsorbed or metabolized by the kidneys. Acidic gel chromatography of spot and 24-hour urine samples showed a CRH IR peak at CRH41 standard elution position (Kd = 0.5), indicating that the molecular form in urine is similar to the 41-residue standard. Pregnancy-induced hypertension correlated positively with plasma CRH IR (r = 0.62, p less than 0.001) and spot urine CRH IR (r = 0.46, p less than 0.01), and negatively with parity (r = -0.60, p less than 0.001). Plasma CRH IR and parity also negatively correlated (r = -0.41, p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

The corticotrophin releasing hormone test in late pregnancy: lack of adrenocorticotrophin and cortisol response

Biologically active corticotrophin-releasing-hormone (CRH) is produced by the placenta in large amounts and can be measured in the maternal circulation during third trimester of pregnancy. Its physiological significance is unknown. To further investigate the action of CRH in pregnancy, we performed a standard CRH-test (1 micrograms/kg synthetic human CRH) in seven pregnant women 1 week prior to their calculated delivery data and 4-5 weeks post-partum. No response of plasma ACTH to CRH administration could be measured in any of the third trimester pregnant women. Post-partum, basal ACTH levels were significantly lower (1.6 +/- 0.3 vs 5.3 +/- 0.2 pmol/l) and reacted promptly to CRH administration (1.6 +/- 0.3-4.2 +/- 0.5 pmol/l; P less than 0.05). Concentration of cortisol in plasma and salivary cortisol paralleled the ACTH response to administration of CRH. However, one pregnant woman experienced physical and emotional stress during the CRH-test and reacted with a sharp rise in cortisol secretion. The lack of the ACTH and cortisol response in this study to exogenously administered CRH in third trimester pregnancy may be due to high circulating glucocorticoid concentrations, desensitization of the pituitary corticotroph and/or in part due to circulating specific CRH-carrier protein.

Naloxone-induced ACTH release in man is inhibited by clonidine

1. Adrenergic mechanisms play an important role in regulation of ACTH release. We used the alpha 2-adrenergic agonist, clonidine, as a central nervous system inhibitor of ACTH release to see if it would alter naloxone-induced ACTH secretion in normal human volunteers. 2. There was a significant blunting of the mean peak level of ACTH and the mean peak change of ACTH from basal as well as the area under the ACTH-time curve when clonidine was given prior to naloxone. 3. We conclude that clonidine, by blocking central noradrenergic pathways, which stimulate corticotropin-releasing hormone secretion, inhibits naloxone-induced ACTH secretion. This suggests that naloxone causes ACTH release through these same central noradrenergic pathways.