Plasma cortisol and corticosterone concentrations in the golden hamster, (Mesocricetus auratus)

Because some recent studies of hamster adrenocortical function have depended on older studies that may have been inadequate or misinterpreted, the present study re-examined plasma corticosterone and cortisol concentrations in hamsters under several conditions to determine which plasma glucocorticoid predominated in this animal. Sensitive radioimmunoassays were used to measure separately the two glucocorticoids in the basal condition, after adrenocorticotropin (ACTH) treatment, after acute stress, and after chronic stress. In the basal condition, corticosterone concentrations were 3-4 times higher than those of cortisol. After stimulation, this difference disappeared, but rarely were any hamster's cortisol levels higher than their corticosterone levels. Both ACTH and acute stress elevated plasma corticosterone and cortisol concentrations, but only plasma cortisol concentrations were elevated following chronic stress. The dissociation between cortisol and corticosterone concentrations after chronic stress suggests that the two glucocorticoid hormones in the hamster may be regulated independently. The data also indicate that both corticosterone and cortisol should be measured when assessing adrenocortical function in the hamster.     

Pituitary-adrenocortical responses to the first dyadic encounters in male rhesus monkeys: effect of dominance relationship

Male rhesus monkeys unfamiliar with each other were paired in a cage, and blood samples were collected before and a few hours after pair formation. Adrenocorticotrophic hormone (ACTH) and cortisol levels in each blood sample were measured. Dominant-subordinate status was ascertained through two rank tests, the food competition test and the agonistic behavior test, which were performed immediately after pair formation. As a result, the dominance relationship was determined in seven pairs formed from five animals, and the differences in ACTH and cortisol values between the dominant and subordinate animal in these pairs were compared statistically. The day after the first encounter, a second encounter was conducted in randomly selected pairs of monkeys. In the first encounters, higher levels of both ACTH and cortisol were detected in dominant animals in comparison to subordinate animals. Changing the animal's partner altered the stress responses whenever the animal's dominant-subordinate status changed. The elevated levels of ACTH and cortisol in dominant animals disappeared on the day after the first encounter. In dominant animals, the pituitary-adrenocortical stress response reacts sharply to situational demands, whereas subordinate animals have a weaker response. This acute stress response is different from a chronic stress response. When the subordinate animal cannot escape, its hypothalamic-pituitary-adrenocortical axis appears to be suppressed.     

The pituitary-adrenal response to ether stress in the spontaneously hypertensive and normotensive rat

The pituitary-adrenal response to ether stress in the spontaneously hypertensive (SHR) and normotensive (WKYN) rat was investigated at three time intervals: 0, 30, and 60 min after exposure to ether vapor. Plasma corticosterone concentrations were significantly higher in the WKYN than SHR rat before stress (0 min), and 30 min after stress. However, 60 min following ether stress the magnitude of increase in plasma and adrenal concentration of corticosterone over basal values was greater in the SHR line than in the WKYN line. The adrenal response to IV administration of 100 μU of ACTH was equivalent in the two lines. The data suggest that the prolonged adrenal response to ether stress in the SHR line is the result of a greater or more prolonged secretion of ACTH in that line than in the WKYN animals.     

Effect of voluntary wheel running on circadian corticosterone release and on HPA axis responsiveness to restraint stress in Sprague-Dawley rats.

Adaptations of the hypothalamic-pituitary-adrenal (HPA) axis to voluntary exercise in rodents are not clear, because most investigations use forced-exercise protocols, which are associated with psychological stress. In the present study, we examined the effects of voluntary wheel running on the circadian corticosterone (Cort) rhythm as well as HPA axis responsiveness to, and recovery from, restraint stress. Male Sprague-Dawley rats were divided into exercise (E) and sedentary (S) groups, with E rats having 24-h access to running wheels for 5 wk. Circadian plasma Cort levels were measured at the end of each week, except for week 5 when rats were exposed to 20 min of restraint stress, followed by 95 min of recovery. Measurements of glucocorticoid receptor content in the hippocampus and anterior pituitary were performed using Western blotting at the termination of the restraint protocol. In week 1, circadian Cort levels were twofold higher in E compared with S animals, but the levels progressively decreased in the E group throughout the training protocol to reach similar values observed in S by week 4. During restraint stress and recovery, Cort values were similar between E and S, as was glucocorticoid receptor content in the hippocampus and pituitary gland after death. Compared with E, S animals had higher plasma ACTH levels during restraint. Taken together, these data indicate that 5 wk of wheel running are associated with normal circadian Cort activity and normal negative-feedback inhibition of the HPA axis, as well as with increased adrenal sensitivity to ACTH after restraint stress.     

Stress and ACTH increase circulating concentrations of 3 alpha-androstanediol in female rats.

The present experiments were carried out to determine what physiological conditions are responsible for the acute increases in serum levels of 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-androstanediol, 3 alpha-Adiol) which are seen in the intact estrous female rat within 15-30 min after mating. Blood samples were obtained from proestrus rats immediately before and 20 min after injection of exogenous hormones or initiation of stress procedures, and plasma concentrations of 3 alpha-Adiol and/or progesterone (P) were measured in these samples by RIA. Intravenous injections of ovine LH (5, 15, or 45 micrograms) or saline resulted in equivalent significant increases in plasma 3 alpha-Adiol 20 min after injection. In contrast, dose-dependent increases in 3 alpha-Adiol were seen after intravenous injection of 0 (acidic saline vehicle), 2, 4, or 8 ng ACTH1-24 to dexamethasone-pretreated rats. The highest ACTH1-24 dose also resulted in a significant increase in plasma P concentration. In a third experiment, a significant increase in 3 alpha-Adiol concentration above baseline was seen at 20 min after onset of restraint stress; in this case plasma P concentrations did not increase significantly. Finally, blood samples were obtained after onset of ether/jugular venipuncture stress two days after ovariectomy (ovx), adrenalectomy (adx), or ovx+adx on diestrus. The plasma 3 alpha-Adiol response to stress was normal in intact sham-operated and non-operated groups of controls, but was significantly diminished in the ovx and the adx groups to 28.4% of that shown by the intact animals. Circulating 3 alpha-Adiol concentrations were undetectable in 22/26 samples obtained in the ovx+adx group. These data demonstrate that plasma concentrations of 3 alpha-Adiol increase in response to stress or ACTH but not LH, and that both the ovary and the adrenal contribute to this increase.     

Adrenocorticotropin and corticosterone levels in pre-weanling spontaneously hypertensive rats

Circulating plasma ACTH and corticosterone levels were measured in spontaneously hypertensive rats (SHR) and the corresponding, normotensive Wistar-Kyoto (WKY) strain at 10 and 20 days of age. In addition, stored levels of ACTH were measured in the pituitary glands of these animals. Circulating corticosterone levels were significantly lower, in both strains, at 10 days than at 20 days. Although the glucocorticoid was undetectable in WKY animals at 10 days, significant levels were observed in age-matched SHR. No difference in corticosterone concentrations was observed between the two strains at 20 days. Circulating ACTH levels did not reflect the values for circulating glucocorticoids. There were no significant differences in the levels of ACTH between strains or between age groups. Moreover, pituitary stores of ACTH between animals of different strains and ages were not found to be significantly different among any of the groups tested. These results demonstrate that there is a difference in circulating corticosterone levels between spontaneously hypertensive and Wistar-Kyoto rats at 10 days postnatally which is not evident just prior to weaning (20 days). This difference is not due to variations in stored or circulating ACTH. Indeed, ACTH levels are high at a time (10 days) when corticosterone is low - thus suggesting that the difference may reside within the responsiveness of the adrenal cortex.     

Vasopressin pressor receptor-mediated activation of HPA axis by acute ethanol stress in rats

The plasma arginine vasopressin (AVP), ACTH, and corticosterone levels and the hypothalamic corticotropin-releasing hormone (CRH) content were measured after oral administration of 1 ml of 75% ethanol to rats, a model known to induce acute gastric erosions and stress. Elevated plasma AVP, ACTH, and corticosterone levels were detected 1 h after ethanol administration. Treatment with the vasopressin pressor (V(1)) receptor antagonist [d(CH(2))(5)Tyr(Me)-AVP] before ethanol administration significantly reduced the ACTH and corticosterone level increases. A higher hypothalamic CRH content was measured at 30 or 60 min after ethanol administration. V(1) receptor antagonist injection, 5 min before ethanol administration, inhibited the rise in hypothalamic CRH content. The protein synthesis blocker cycloheximide prevented the hypothalamic CRH content elevation after stress. The AVP-, CRH-, and AVP + CRH-induced in vitro ACTH release in normal anterior pituitary tissue cultures was also prevented by pretreatment with the V(1) receptor antagonist. The results support the hypothesis that stress-induced AVP may not only act directly on the ACTH producing anterior pituitary cells but also indirectly at the hypothalamic level via the synthesis and release of CRH.     

Plasma acth and cortisol levels in depressed patients: Relation to dexamethasone suppression test

Blood samples collected from normal subjects and newly hospitalized depressed patients at 8 AM on the day before and at 8 AM and 4 PM the day after receiving dexamethasone, 1 mg orally at 11 PM, were analyzed for ACTH and cortisol. The mean plasma ACTH values of these two groups were not significantly different at any of the times, while the cortisol levels of the depressed patients were significantly higher than those of the normal subjects at 8 AM pre-dexamethasone (P<0.001). There was no correlation between plasma ACTH and cortisol values in either group. The cortisol responses to dexamethasone in depressed patients revealed two subgroups. In one subgroup, the cortisol was suppressed as much as in normal subjects, but in the other, cortisol levels were not suppressed. The post-dexamethasone ACTH rebounded at 4 PM in the latter subgroup to higher values than in the subgroup with suppressed cortisol levels and in the normal subjects. After dexamethasone, the ACTH values were negatively correlated with plasma cortisol only in the normal subjects (P<0.01), not in the depressed patients. These results indicate that ACTH levels do not account for the elevated cortisol and the failure of dexamethasone to suppress cortisol levels in some depressed patients.     

Effect of ACTH and glucocorticoids on plasma prolactin levels in the male rat

Relationships between prolactin and adrenal secretion were studied in the adult male rat by different experimental approaches. Administration of a long acting 1-24 ACTH preparation during 11 days induced a significant decrease in plasma prolactin levels. Adrenalectomy on the contrary resulted in an increase of prolactin levels that were not affected by ACTH treatment. Dexamethasone administration to intact or adrenalectomized animals resulted in a significant reduction of plasma prolactin in both cases. In order to elucidate if the inhibitory effect of the adrenal stimulation on prolactin was mediated through the blockade of endogenous ACTH, stimulation of hypothalamic-pituitary-adrenal axis with chronic intermittent immobilization stress was performed. Stress induced a significant elevation in plasma corticosterone levels, together with a decrease in prolactin values. These data indicated that the inhibitory role of ACTH and stress on prolactin secretion was mediated through the adrenal glucocorticoid stimulation.     

Characterization of pituitary–adrenocortical activity in the Malayan flying fox (Pteropus vampyrus)

Pituitary–adrenocortical and gonadal endocrine activity was investigated in a captive colony of Pteropus vampyrus, a highly social Old World fruit bat. Both cortisol and corticosterone were present in plasma, at a ratio of approximately 5:1, respectively. Glucocorticoid but not testosterone levels significantly increased prior to and concomitant with the evening active period. Restraint stress for 15–60 min resulted in a significant and rapid increase in plasma levels of adrenocorticotropic hormone (ACTH) and glucocorticoids. ACTH levels quickly returned to baseline following restraint whereas glucocorticoid levels remained elevated for at least 30 min after restraint ended. Plasma ACTH levels after stress were similar to levels reported after stress in other mammals. Stress-induced glucocorticoid levels were several-fold greater than those reported for most mammals. Restraint for 15 min significantly inhibited testosterone levels. Restraint stress did not affect hormone levels on the morning following restraint. Brief capture, handling, and release of the animals did not elicit increases in these hormones. The physiological responsiveness of the pituitary and adrenal glands, along with P. vampyrus’s documented seasonality and range of social behaviors, makes these bats an excellent model for exploring the general physiology of the hypothalamic–pituitary–adrenal and hypothalamic–pituitary–gonadal axes, as well as social influences on these axes.     

Adrenocorticotropin secretion rates following histamine injection in adult and newborn dogs.

The metabolic clearance rate (MCR) for ACTH in adult dogs was previously shown not to vary significantly with varying plasma ACTH concentrations or among dogs. This is confirmed here for pups aged 1-7 days. Hence, ACTH secretion rates can be continuously calculated from a continuous function of plasma ACTH vs. time. Each of seven adult dogs under Nembutal anesthesia received two or three intravenous (i.v.) injections of histamine with increasing doses. The first injections in each dog ranged from 7 to 50 mug/kg, while the last dose was 62-108 mug/kg. A total of 16 injections were given. Twelve pups (two litters of six) aged 1-7 days each received one injection of histamine of 76-116 mug/kg (i.v.). ACTH concentrations in plasma were determined by an adrenal cell suspension bioassay before, and 6 times after each injection. Nine pups also underwent determinations of their MCR for ACTH, with plateau concentrations determined at three times during an ACTH infusion. Continuous curves of ACTH secretion rates were calculated for all 28 histamine injections, showing that all except the 1-day-old pups secrete considerable ACTH when stressed. Compared to adult dogs, the pups show lower secretion rate peaks and shorter periods of rapid secretion. Changes in plasma glucocorticoids also suggest that the adrenal cortex of newborn dogs can respond to ACTH by increased glucocorticoid secretion.     

The effect of MSH/ACTH 4-10 on delayed response performance and post-test locomotor activity in rats

Delayed response performance was measured in male, Long-Evans rats 1 hr after IP administration of various doses of MSH/ACTH 4-10 or control in a Hunter delayed reaction apparatus. Additional treatments consisting of naloxone 500 micrograms/kg (IP) and naloxone 500 micrograms/kg in conjunction with MSH/ACTH 4-10 95 micrograms/kg were also administered. Directly after delayed response performance was assessed, gross locomotor activity was determined. MSH/ACTH 4-10, at a dose of 95 micrograms/kg, significantly enhanced retention of a visual stimulus, while MSH/ACTH 4-10, at doses of 195 and 285 micrograms/kg, significantly impaired delayed response performance. Naloxone treatment resulted in significantly impaired delayed response performance when compared to control. However, naloxone plus MSH/ACTH 4-10 treatment failed to produce a significant difference from control in the delayed response performance paradigm. In post-test locomotor activity determination, an apparent dose-response existed for MSH/ACTH 4-10 with the two highest doses (190 and 285 micrograms/kg) resulting in significantly increased locomotor activity. The observed delayed response performance data support theories implicating MSH/ACTH peptides in attentional processes involving visual stimuli. The fact that large doses of MSH/ACTH 4-10 disrupt delayed response performance while increasing post-test activity suggest that an optimum level of effect caused by the MSH/ACTH peptide exists in this paradigm.     

Combined ACTH and glucocorticoid treatment improves survival and organ maturation in premature newborn calves

Glucocorticoids play an important role in prenatal organ maturation in many species. In humans, maternal treatment with synthetic glucocorticoids improves neonatal adaptation of prematurely born infants. In cows, pre-term calf survival is improved following a single maternal glucocorticoid administration. We hypothesized that stimulation of endogenous cortisol secretion by adrenocorticotropin (ACTH) treatment combined with maternal dexamethasone treatment, would be even more efficient in stimulating organ maturation in the prematurely delivered calf. Three groups of premature calves were delivered by caesarian section at 90% of gestation length from dams which were either untreated or injected with dexamethasone before delivery, combined with either prenatal or postnatal ACTH treatment to the calf. During the first 24h after birth, thermoregulation, blood chemistry, liver values and organ weights were recorded. In the untreated calves, survival was significantly correlated with blood oxygenation, sodium and calcium levels at the moment of birth. There were marked maturational effects of the treatments on body temperature regulation, blood acid-base status, oxygenation, glucose, insulin, IGF-1 levels, weight of the heart, liver, gastrointestinal tract and thymus weight. For many of the measured metabolic, endocrine and organ weight parameters, the intrauterine ACTH treatment was associated with improved values relative to the postnatal ACTH treatment, which appeared to have no immediate effect on calf viability. In conclusion, the premature calf delivered by caesarian section at 90% of gestation length showed blood chemistry, metabolic, endocrine and organ growth characteristics that indicated severe prematurity. However, the maturation of organ function in newborn premature calves following maternal glucocorticoid injections was further enhanced if is was preceded by intra-fetal injections of ACTH.     

Long-term salt loading impairs pituitary responsiveness to ACTH secretagogues and stress in rats

Male Wistar rats were allowed to drink tap water ad lib (W), 2% saline (S) or 2% saline containing dexamethasone (S + D, 1 mg/l) for 7 days. On the 8th day rats were subjected to a 3-min ether stress. Plasma ACTH, corticosterone and prolactin concentrations were determined before and after ether exposure. Prestress concentrations of plasma ACTH were low and did not vary among the three groups. In response to ether stress W rats exhibited twice as high plasma ACTH concentrations as did S rats. Rats of the S + D group exhibited a small but statistically significant ACTH response. Plasma corticosterone concentration in S rats was increased while in S + D rats was significantly decreased under resting conditions compared to that in W rats. Ether stress caused large increases in plasma corticosterone concentrations in W and S rats while a small but statistically significant increase was observed in S + D rats. Prolactin responses to ether were smaller in groups S and S + D than in group W. To test whether the decreased ACTH response to ether exposure was a result of a decreased sensitivity of corticotrope cells to corticotropin releasing factor (CRF)-41 or arginine vasopressin (AVP), adenohypophysial fragments from W, S and S + D rats were incubated in the presence of different doses of CRF-41 or AVP. Pituitary fragments obtained from W rats secreted larger amounts of ACTH than did pituitaries from S rats in response to either CRF-41 or AVP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Endocrine patterns before and after examination stress in males and females

Plasma levels of cortisol, adrenocorticotropin (ACTH), and growth hormone (GH), were determined by radioimmunoassay in medical students just before (Exp.1) plasma values of cortisol were higher than their control values in both sexes, statistically significantly, however, only in males. The difference of cortisol behavior between the sexes was not significant. The males' ACTH values were lower than their control levels, but there was no such difference in the females. Plasma levels and differences of growth hormone varied greatly in both sexes. After the examination (Exp.2) plasma values of cortisol were unaffected compared with their control values in both sexes. The ACTH values were lower than the control values in both sexes, significantly though only in the males. The GH values were higher than control values in the males but not in the females. The results are in line with previous observations suggesting that psychological stress is associated with slightly different hormonal effects in males and females.     

Long-term hypoxia enhances proopiomelanocortin processing in the near-term ovine fetus

Secondary stressors in long-term hypoxic (LTH) fetal sheep lead to altered function of the hypothalamic-pituitary-adrenal axis. Although ACTH is considered the primary mediator of glucocorticoid production in fetal sheep, proopiomelanocortin (POMC) and 22-kDa pro-ACTH (22-kDa ACTH) have been implicated in the regulation of cortisol production in the ovine fetus. This study was designed to determine whether POMC expression and processing are altered after LTH. Pregnant ewes were maintained at high altitude (3,820 m) from day 30 of gestation to near term, when the animals were transported to the laboratory. Reduced Po2 was maintained by nitrogen infusion through a maternal tracheal catheter. On days 139-141, fetal anterior pituitaries were collected from normoxic control and LTH fetuses. We measured POMC and corticotrophin-releasing factor type 1 receptor (CRF1-R) mRNA using quantitative real-time PCR, and we used Western blot analysis for quantitation of ACTH, ACTH precursor, and CRF1-R proteins. We measured plasma ACTH1-39 using a two-site immunoradiometric assay specific for ACTH1-39. Plasma ACTH precursors were measured by ELISA. Anterior pituitary POMC mRNA levels were not different between groups, whereas CRF1-R levels were significantly higher in the LTH anterior pituitaries compared with control (P<0.05). In contrast, protein levels of POMC, CRF1-R, 22-kDa ACTH, and ACTH1-39 were significantly lower in the LTH group. Plasma concentrations of both ACTH precursors and ACTH1-39 were significantly elevated in LTH fetuses, whereas the ratio of plasma precursors to ACTH was significantly lower. We conclude that LTH results in enhanced POMC processing and/or release to ACTH and increased hypothalamic drive.     

DHEA,PREG and Their Sulphate Derivatives on Plasma and Brain After CRH and ACTH Administration

The term neurosteroids applies to steroids that are synthesized in the nervous system, either de novo from cholesterol or from steroid hormone precursors. RIA was used to determine plasma and brain levels of the neurosteroids pregnenolone (PREG), ehydroepiandrosterone (DHEA), and their sulfate derivatives (PREG-S and DHEA-S) in male and female rats after administration of two typical stress hormones: corticotropin-releasing hormone (CRH) and adrenocorticotropin hormone (ACTH). In all cases, the parameters measured were detectable in plasma and brain. PREG, PREG-S, and DHEA increased significantly in plasma and brain after CRH and ACTH administration in males and females. Because neurosteroids play an important role in mammalian physiology, including that of humans, stress situations may alter the physiological functions regulated by these neurosteroids.     

慢性应激抑郁状态对大鼠外周神经内分泌因子生物节律的影响

目的：探讨慢性不可预见性应激状态下大鼠外周神经内分泌因子昼夜节律的表达特点。方法：成年雄性SD大鼠60只,随机分为模型组和对照组（n=30）,采用束缚、摇晃、鼠笼倾斜、湿垫料、冷刺激、拥挤（整夜）、断食或断水、夹尾、昼/夜颠倒等慢性不可预知性温和刺激结合孤养方式,每天暴露于2种应激原中饲养21 d,建立抑郁症模型。测定应激前后大鼠糖水偏爱、旷场行为及高架十字迷宫行为学变化。连续24 h分6个时间点（ZT1、ZT5、ZT9、ZT13、ZT17、ZT21）处死动物取血,每个时间点处死5只大鼠。放免法测定6个时间点血清促肾上腺皮质激素（ACTH）含量,ELISA法测定6个相同时间点血浆皮质酮（CORT）、褪黑素（MT）、血管活性肠肽（VIP）含量,采用单一余弦法比较2组大鼠上述各指标的节律周期、振幅、峰值相位、中值的变化特点。结果：与对照组相比,模型大鼠体重增加值明显降低（P<0.01）,各项行为学评分均显著减少（P<0.01）。慢性应激至抑郁样行为充分表达后,血浆ACTH、CORT的相位完全相反,时相大幅度提前,含量波动幅度减小,昼夜分泌节律紊乱;MT的24 h分泌节律完全丧失且整体水平下降,表达量显著降低;VIP虽仍存在24 h节律,但振幅明显降低,峰相位也延迟6 h,且表达量显著提高。结论：慢性应激抑郁状态可导致大鼠外周神经内分泌激素的近日节律非同步于SCN,表现为昼夜节律性和激素分泌量的异常。     

Time course of vasopressin and oxytocin secretion after stress in adrenalectomized rats.

To characterize the participation of vasopressin (AVP) and oxytocin (OT) in hypothalamus-pituitary-adrenal regulation after adrenalectomy (ADX), we evaluated corticosterone, ACTH, AVP and OT plasma concentrations and AVP and OT content of the paraventricular nucleus (PVN) at different periods (3 h, 1, 3, 7 and 14 days) in sham or ADX rats under basal conditions and after immobilization stress. ADX animals showed undetectable corticosterone levels, while sham animals showed a marked increase in corticosterone and ACTH 3 h after surgery, then lowering to basal control levels. ADX rats showed high basal ACTH levels with a triphasic response without changes after immobilization. After three hours, the ADX group showed higher OT levels than the sham group. OT was increased after immobilization stress in sham and ADX groups. AVP plasma levels did not change throughout the basal or stress studies in either group. There was a decrease in hypothalamic AVP content 1 and 3 days after ADX under basal and stress conditions. Plasma osmolality showed a significant decrease in the ADX group at 3, 7, and 14 days. In conclusion, there are different pituitary-adrenal axis set points after removal of the glucocorticoid negative feedback. The role of vasopressinergic and oxytocinergic neurons in the ACTH secretion after ADX or immobilization stress appears to differ. Magnocellular AVP is unlikely to contribute to ACTH secretion in response to ADX or immobilization stress. On the other hand, OT is elicited by immobilization stress and might contribute to the ACTH secretion during short-term ADX.     

Plasma 6beta-hydroxycortisol measurements for assessing altered hepatic drug metabolizing enzyme activity

To study the usefulness of 6beta-hydroxycortisol (6betaOHF) measurements for assessing hepatic drug metabolizing enzyme activity, plasma 6betaOHF and cortisol were measured in 22 patients with alcoholic liver disease after at least 2 weeks of alcohol abstinence, in 5 patients with severe Cushing's syndrome and in 12 healthy non-drinker subjects. Blood samples were drawn under resting conditions during midnight, in the morning at 0800 h, after a 1-mg overnight dexamethasone test and after ACTH administration. Plasma cortisol and 6betaOHF were determined with radioimmunoassay. In patients with alcoholic liver disease, the plasma cortisol levels at midnight and 0800 h, as well as after the administration of dexamethasone and ACTH were not different from corresponding values measured in non-drinker controls. In addition, these patients with alcoholic liver disease had similar plasma 6betaOHF levels at midnight, 0800 h and after dexamethasone administration as compared to corresponding values in controls. By contrast, ACTH administration in patients with alcoholic liver disease resulted in a significantly (p<0.05) larger increase of plasma 6betaOHF (from 106 +/- 22 to 1102 +/- 106 ng/dl, mean +/- SE) as compared to that found in controls (from 74 +/- 3 to 337 +/- 76 ng/dl). The markedly increased 6betaOHF response to ACTH administration in patients with alcoholic liver disease was similar to that measured in patients with severe Cushing's syndrome, in whom increased and non-suppressible plasma cortisol levels were accompanied by markedly elevated plasma 6betaOHF levels. These results indicate that alcohol abstinence in patients with alcoholic liver disease is associated with an exaggerated 6betaOHF response to ACTH and that this abnormality may prove to be a clinically useful parameter for a sensitive detection of altered drug metabolism present in these patients.