Comparison of growth hormone and prolactin stimulation induced by chlorimipramine and desimipramine in man in connection with chlorimipramine metabolism

Neuroendocrine responsivity to clomipramine challenge test in neuroleptic naive psychotic patients before and after treatment with haloperidol

The prolactin, cortisol and growth hormone (GH) responses to intravenous administration of 25 mg clomipramine (CMI) were studied in young male psychotic patients who had never received neuroleptics and suffered from schizophrenia (13 patients), delusional disorder (three patients) or schizoaffective disorder (one patient). The test was repeated after 1 month in 16 patients who were hospitalized and treated with haloperidol in doses appropriate for best clinical response (range: 7.5–40 mg daily). Symptomatology was assessed by the Brief Psychiatric Rating Scale (BPRS). There was no association of the side effects caused by the administration of CMI (nausea and emesis) to the GH responses. The side effects appeared significantly less in the after treatment trials. Treatment with haloperidol did not influence the response patterns of the three hormones. An indication that high haloperidol doses may inhibit the prolactin response to CMI was obtained when the data were compared between low (7.5–10 mg/day, mean 9.7) and high (15–40 mg/day, mean 22.0) dose subgroups. Significant positive correlations were found between the prolactin and cortisol responses to CMI in the drug-free state, and the scores in the positive symptoms subscale of the BPRS. The degree of improvement did not correlate to any of the hormonal data.

Serotonergic vulnerability and depression: assumptions, experimental evidence and implications

In recent years, the term serotonergic vulnerability (SV) has been used in scientific literature, but so far it has not been explicitly defined. This review article attempts to elucidate the SV concept. SV can be defined as increased sensitivity to natural or experimental alterations of the serotonergic (5-HTergic) system. Several factors that may disrupt the 5-HTergic system and hence contribute to SV are discussed, including genetic factors, female gender, personality characteristics, several types of stress and drug use. It is explained that SV can be demonstrated by means of manipulations of the 5-HTergic system, such as 5-HT challenges or acute tryptophan depletion (ATD). Results of 5-HT challenge studies and ATD studies are discussed in terms of their implications for the concept of SV. A model is proposed in which a combination of various factors that may compromise 5-HT functioning in one person can result in depression or other 5-HT-related pathology. By manipulating 5-HT levels, in particular with ATD, vulnerable subjects may be identified before pathology initiates, providing the opportunity to take preventive action. Although it is not likely that this model applies to all cases of depression, or is able to identify all vulnerable subjects, the strength of the model is that it may enable identification of vulnerable subjects before the 5-HT related pathology occurs.

S-Citalopram in neuroendocrine challenge-tests: serotonergic responsivity in healthy male and female human participants

The aim of the present study was to assess the usefulness of the selective serotonin-reuptake-inhibitor S-Citalopram as a serotonergic challenge probe in 24 healthy male and 24 healthy female participants. The participants received a single oral dose of 10 and 20mg of S-Citalopram in a placebo-controlled double blind crossover design. In female subjects phases of the menstrual cycle were controlled. Changes in concentrations of cortisol in saliva were used to indicate serotonergic reactivity. S-Citalopram induced a reliable dose dependent rise in cortisol concentrations. Results reveal a clear dose-response relationship in both sexes. However, in contrast to the 10mg condition the dosage of 20mg led to significantly higher cortisol levels in females, whereas no differences could be observed with respect to different phases of the menstrual cycle (follicular vs. luteal). Adverse side effects were reported only after 20mg. The results clearly indicate that the dosage of 10mg should be preferred when challenging males and females. Results will be discussed with regard to the further use of S-Citalopram in neuroendocrine challenge tests.

Comparison of the effects of citalopram and escitalopram on 5-Ht-mediated neuroendocrine responses

Acute oral administration of selective serotonin re-uptake inhibitors (SSRIs) increases plasma cortisol by facilitating brain serotonin activity. Recently, salivary cortisol sampling has grown in popularity as a noninvasive means of assessing HPA axis activity. The aim of the present study was to find out whether acute oral administration of the SSRI, citalopram, increases salivary cortisol in healthy volunteers and whether the increase produced by an equivalent dose of its active isomer, escitalopram, is greater. A total of 15 healthy subjects were tested on three occasions receiving either oral citalopram (20 mg), escitalopram (10 mg), or placebo in a double-blind, randomized, crossover design. Salivary cortisol and plasma cortisol and prolactin were measured for 240 min after each treatment. Relative to placebo, both citalopram and escitalopram increased salivary and plasma cortisol levels with no evidence of consistent differences between them. Plasma prolactin concentration was not altered by either active treatment. Plasma and salivary cortisol responses after citalopram but not escitalopram correlated significantly. The present study does not support an enhanced effect of escitalopram on 5-HT-mediated neuroendocrine responses.

Paroxetine as a 5-HT neuroendocrine probe

RATIONALE

Acute administration of 40 mg paroxetine (a selective serotonin reuptake inhibitor) reportedly increases plasma cortisol in human subjects. This suggests that paroxetine may be a useful tool to probe brain serotonin function.

OBJECTIVE

To investigate a dose-response relationship for paroxetine administration, and to determine whether a lower dose of paroxetine is sufficient to increase plasma ACTH and cortisol.

METHODS

Twenty subjects were tested on three occasions in a double-blind, cross-over design receiving: (a) placebo, (b) paroxetine 20 mg and (c) paroxetine 40 mg administered orally at 8.00 a.m. In addition, five of the 20 subjects received paroxetine 20 mg plus cyproheptadine (a 5-HT(2) receptor antagonist) 4 mg and four subjects were given paroxetine 40 mg plus cyproheptadine 4 mg in an open manner. Plasma ACTH and cortisol levels were measured prior to administration and every hour for 6 h thereafter.

RESULTS

Paroxetine, particularly 20 mg rather than 40 mg, significantly increased plasma ACTH and cortisol. Paroxetine 40 mg but not 20 mg caused significantly more nausea than the placebo. Cyproheptadine attenuated ACTH and cortisol responses to 20 mg but not to 40 mg paroxetine.

CONCLUSIONS

Low-dose (20 mg) paroxetine has greater potential utility than larger doses as a neuroendocrine challenge test. The endocrine responses to paroxetine are probably mediated at least partially by 5-HT(2A/2C) receptors.

Prolactin responses to acute clomipramine and haloperidol of male schizophrenic patients in a drug-free state and after treatment with clozapine or with olanzapine

Atypical neuroleptics share a common feature, showing higher affinity for 5-HT2 receptors than for D2 dopamine receptors, but show considerable differences in their clinical and pharmacological properties. In clinical doses, they occupy serotonergic receptors near saturation, but show considerable differences regarding the D2 receptor occupancies, with clozapine showing the lowest degree of occupation. We assessed serotonergic and dopaminergic receptor responsiveness in two groups of male schizophrenic patients, one treated with the atypical neuroleptic clozapine (14 patients, doses 200-600 mg/d) and the other treated with olanzapine (11 patients, doses 10-30 mg/d). We measured the prolactin responses to the acute administration of a serotonergic drug, clomipramine, and a dopaminergic one, haloperidol. Tests were first performed in the drug-free state, and were repeated after the patients had been treated with stable doses of either drug for six weeks. Clomipramine administration induced significant increases of prolactin in the drug-free state. These responses were eliminated after treatment of the patients with either drug, thereby indicating a high 5-HT receptor occupancy by both clozapine and olanzapine. The prolactin responses to haloperidol were not altered after treatment with clozapine, but were significantly reduced after the olanzapine treatment. The baseline prolactin levels were not influenced by clozapine treatment, and were moderately but significantly increased after treatment with olanzapine. The results indicate that there is a difference between the two drugs in their capacity to block dopamine receptors at the hypothalamus-pituitary level, and match the results obtained by SPECT receptor binding studies for striatal dopamine receptors.

Changes in central serotonergic function as a correlate of duration of illness in paranoid schizophrenia

There is evidence that the duration of untreated psychosis may affect both the course and outcome of treatment in schizophrenic patients. In the present study, we used neuroendocrine probes to test the hypothesis that untreated psychosis may induce time-dependent changes in central serotonergic and dopaminergic neurotransmission. Prolactin responses to the administration of clomipramine (i.v.) and haloperidol (i.m.) were measured in healthy control subjects and in 16 never-treated male patients with DSM-IV diagnoses of schizophreniform or schizophrenic disorders of paranoid subtype, both before and after 5 weeks of treatment with haloperidol. In the drug-free state, schizophrenic patients exhibited significantly increased prolactin responses to clomipramine administration compared with both the healthy control subjects and the schizophreniform patients. Maximum prolactin responses to clomipramine in the total group of patients were positively correlated with the duration of psychotic illness and negatively correlated with changes in Positive and Negative Syndrome Scale (PANSS) total, negative symptoms and general psychopathology scores after 5 weeks of treatment with haloperidol. Prolactin responses to haloperidol challenge in the drug-free state were lower in the schizophreniform group than in the control and the schizophrenic groups, but the differences did not reach statistical significance. The results provide evidence that the persistence of psychotic psychopathology induces secondary neuroadaptive effects, which seem to involve changes in central serotonergic function.

Neuroendocrine predictors of response to intravenous clomipramine therapy for refractory obsessive-compulsive disorder

The current study examines the neuroendocrine response to intravenous clomipramine (IV CMI) in oral CMI-resistant obsessive-compulsive disorder (OCD) patients on day 1 and day 14 of treatment to identify predictors of response. Forty-four OCD patients with an inadequate response or poorly tolerant to oral CMI were begun at 25 mg IV CMI, increasing to 250 mg by day 10, and continuing on that dose to day 14. On day 1, plasma levels of prolactin (PRL), growth hormone (GH), and cortisol were obtained immediately before the 25 mg IV infusion, and at five 30-minute time points after the infusion. On day 14, hormonal samples were obtained in a similar fashion. Response was assessed by the Clinical Global Impressions (CGI). Low PRL(MAX) to IV CMI and low cortisol levels overall on day 1 were both significantly associated with clinical response at day 14. An overall increase in growth hormone (GH) secretion during the day 14 testing was associated with positive response. A pronounced PRL response to IV CMI on day 14 was exhibited by the nonresponders, whereas a smaller and later but significant increase in PRL was noted in the responders. The findings suggest that in this sample of oral CMI-resistant patients with OCD, neuroendocrine measures derived from pharmacological challenge with IV CMI are capable of distinguishing IV CMI treatment responders from nonresponders. The limitations of IV CMI as a specific probe of serotonin function are discussed.

The citalopram challenge test in patients with major depression and in healthy controls

Neuroendocrine challenge tests in depressed patients have revealed a blunted hormonal reaction to serotonergic stimuli. In the present study, citalopram was chosen as the serotonergic agent for neuroendocrine stimulation. Compared to earlier challenge agents, citalopram has the advantage of serotonergic selectivity, its application is well tolerated and the possibility of intravenous application reduces pharmacokinetic interference. Sixteen patients suffering from an acute episode of major depression and 16 healthy controls underwent the stimulation procedure with 20 mg of citalopram and placebo. Whereas significant differences in the secretion of prolactin and cortisol between citalopram and placebo challenge were observed in the control group, no differences were found in the group of depressed patients. Comparison of depressed patients and controls showed a significantly blunted prolactin secretion in patients. Differences in cortisol secretion following serotonergic stimulation with citalopram did not become significant. The stimulation procedure was well tolerated in all subjects, although a higher number of side effects was observed in the control group. The amount of side effects did not correlate with the hormone responses. These results are in line with the hypothesis of serotonergic hypofunction in depressed patients. In conclusion, the 20-mg citalopram challenge test is thought to be a promising tool for further investigation of serotonergic function in psychiatric illness.

Parenteral clomipramine challenge in depressed adolescents: mood and neuroendocrine response

BACKGROUND

Major depressive disorder (MDD) in the adolescent demonstrates a unique clinical profile, and pathogenic serotonergic dysregulation is hypothesized. Parenteral clomipramine (CMI) is known to distinguish adult MDD from control, but neurochallenge data are lacking in adolescent MDD.

METHODS

Thirteen drug-free outpatient adolescents who met DSM-III-R criteria for MDD were compared to adolescent controls by acute neuroendocrine and mood response to 12.5 mg of parenteral CMI.

RESULTS

Repeated measures analysis revealed significant changes from baseline for sadness (p < .01) between groups, with normal controls increasing sadness rating after CMI. Prolactin (PRL) maximum change score from baseline was decreased in MDD relative to controls (p < .05). Gender effects on PRL were evident in controls but not in MDD.

CONCLUSIONS

The findings of PRL blunting in adolescent MDD mirrors previous work in adults. A unique finding is the induction of sadness in normal adolescent controls after CMI infusion.

Intravenous clomipramine challenge in obsessive-compulsive disorder: predicting response to oral therapy at eight weeks

BACKGROUND

Challenge with intravenous clomipramine (CMI) is serotonin selective and has been reported to transiently exacerbate symptoms in obsessive-compulsive disorder (OCD) patients, and to predict subsequent response to oral CMI therapy.

METHODS

We administered CMI (12.5 mg, i.v.) to medication free OCD patients (N = 29) and normal controls (N = 22) to characterize neurohormonal response. A subset of OCD patients (26/29), was then treated with either pulse load i.v. or oral CMI followed by 8 weeks of oral CMI therapy.

RESULTS

In response to CMI challenge, OCD patients exhibit blunted cortisol and exaggerated growth hormone response relative to normal controls. OCD patients differ from controls in "sadness" ratings, with control exhibiting increased dysphoria in response to CMI. Growth hormone response to CMI challenge predicts treatment response (> or = 25% decreases YBOCS from baseline) to oral CMI at 8 weeks.

CONCLUSIONS

Growth hormone abnormalities associated with OCD in response to CMI challenge differentiates nonresponders after 8 weeks of oral CMI treatment from responders.

Changes in plasma prolactin during SSRI treatment: evidence for a delayed increase in 5-HT neurotransmission

We studied the effect of the selective serotonin reuptake inhibitor (SSRI), paroxetine, on basal plasma prolactin concentrations in 11 healthy subjects. Subjects were tested before paroxetine, and after 1 and 3 weeks of treatment (20 mg daily). On each test occasion prolactin levels were sampled before and following administration of a placebo capsule, for a total of 4 h. After 3 weeks paroxetine treatment plasma prolactin levels were significantly higher than those seen either pre-treatment or after 1 week of treatment. In contrast, 1 week of paroxetine treatment did not significantly increase prolactin concentrations over pre-treatment values. Plasma concentrations of paroxetine did not differ between 1 and 3 weeks of treatment. The secretion of plasma prolactin is, in part, under the tonic regulation of serotonergic pathways and the present results therefore support animal experimental data suggesting that SSRIs produce a delayed increase in some aspects of brain serotonin neurotransmission.

Nefazodone. A review of its pharmacology and clinical efficacy in the management of major depression

Nefazodone hydrochloride is a phenylpiperazine antidepressant with a mechanism of action that is distinct from those of other currently available drugs. It potently and selectively blocks postsynaptic serotonin (5-hydroxytryptamine; 5-HT) 5-HT2A receptors and moderately inhibits serotonin and noradrenaline (norepinephrine) reuptake. In short term clinical trials of 6 or 8 weeks' duration, nefazodone produced clinical improvements that were significantly greater than those with placebo and similar to those achieved with imipramine, and the selective serotonin reuptake inhibitors (SSRIs) fluoxetine, paroxetine and sertraline. The optimum therapeutic dosage of nefazodone appears to be between 300 and 600 mg/day. Limited long term data suggest that nefazodone is effective in preventing relapse of depression in patients treated for up to 1 year. Analyses of pooled clinical trial results indicate that nefazodone and imipramine produces similar and significant improvements on anxiety- and agitation-related rating scales compared with placebo in patients with major depression. Short term tolerability data indicate that nefazodone has a lower incidence of adverse anticholinergic, antihistaminergic and adrenergic effects than imipramine. Compared with SSRIs, nefazodone causes fewer activating symptoms, adverse gastrointestinal effects (nausea, diarrhoea, anorexia) and adverse effects on sexual function, but is associated with more dizziness, dry mouth, constipation, visual disturbances and confusion. Available data also suggest that nefazodone is not associated with abnormal weight gain, seizures, priapism or significant sleep disruption, and appears to be relatively safe in overdosage. Nefazodone inhibits the cytochrome P450 3A4 isoenzyme and thus has the potential to interact with a number of drugs. Further long term and comparative studies will provide a more accurate assessment of the relative place of nefazodone in the management of major depression. Nonetheless, available data suggest that nefazodone is a worthwhile treatment alternative to tricyclic antidepressants and SSRIs in patients with major depression.

Behavioral and endocrine responses to clomipramine in panic disorder patients with or without alcoholism

Central nervous system serotonin functions may differ between certain subgroups of alcoholics, patients with panic disorder, and healthy volunteers. To investigate these possibilities we administered the serotonin uptake inhibitor, clomipramine (12.5 mg, i.v.), to patients with alcohol dependence, patients with panic disorder with or without alcohol dependence, and healthy volunteers. Alcoholics did not differ from healthy volunteers in their neuroendocrine or behavioral responses. In contrast, patients with panic disorder exhibited marked dysphoric reactions and/or panic attacks following low-dose i.v. clomipramine, whereas their neuroendocrine responses were similar to the other two groups. Patients with panic disorder may have super-sensitive postsynaptic serotonin receptors in areas of their central nervous system, which are important for mood regulation.

A review of GHRH stimulation test in psychiatry

We critically reviewed controlled investigations of the growth hormone releasing hormone (GHRH) stimulation test in depression, anorexia nervosa, bulimia, panic disorder, schizophrenia, and Alzheimer's disease. Comparisons of GH responsiveness between patients and controls within each diagnostic category were equivocal and in some cases contradictory. Factors that may contribute substantially to the inconsistent findings within diagnostic categories include (1) the variability of GHRH-simulated GH among control groups; (2) the lack of uniformity in test procedures and outcome measures; and (3) the age and gender of subjects. In addition, the individual reproducibility of the GHRH stimulation test has not been adequately investigated and until the test's stability within subjects can be determined, the validity of interpretations resulting from the GHRH simulation test are in question.

Clomipramine-induced sleep disturbance does not impair its prolactin-releasing action

The present study was undertaken to examine the role of sleep disturbance, induced by clomipramine administration, on the secretory rate of prolactin (PRL) in addition to the direct drug effect. Two groups of supine subjects were studied under placebo-controlled conditions, one during the night, when sleeping (n = 7) and the other at daytime, when awake (n = 6). Each subject received a single 50 mg dose of clomipramine given orally 2 hours before blood collection. Plasma PRL concentrations were analysed at 10 min intervals and underlying secretory rates calculated by a deconvolution procedure. For both experiments the drug intake led to significant increases in PRL secretion, acting preferentially on tonic secretion as pulse amplitude and frequency did not differ significantly from corresponding control values. During the night clomipramine ingestion altered the complete sleep architecture in that it suppressed REM sleep and the sleep cycles and induced increased wakefulness. As the relative increase in PRL secretion expressed as a percentage of the mean did not significantly differ between the night and day time studies (46 +/- 19% vs 34 +/- 10%), it can be concluded that the observed sleep disturbance did not interfere with the drug action per se. The presence of REM sleep was shown not to be a determining factor either for secretory pulse amplitude and frequency, as, for both, mean nocturnal values were similar with and without prior clomipramine ingestion.

Altered prolactin response to clomipramine rechallenge in healthy subjects

The effect of an initial challenge with the serotonin (5-HT) uptake inhibitor clomipramine (CMI) on subsequent rechallenge was studied in healthy men who served as volunteers. Carefully screened volunteers were assigned to one of three conditions: (1) CMI challenge followed 2 weeks later by CMI rechallenge; (2) placebo challenge followed 2 weeks later by CMI challenge; and (3) CMI challenge followed 4 weeks later by CMI rechallenge. We found significant blunting of the prolactin response to CMI rechallenge 2 weeks (Signed Rank = -12, p = 0.05), but not 4 weeks after an initial challenge. Placebo challenge did not effect CMI challenge 2 weeks later. These findings suggest that a single exposure to IV CMI may cause 5-HT receptor changes that are present 2, but not 4 weeks later. The ramifications of this finding with regard to the use of 5-HT challenge paradigms in a test-retest design are discussed.

Neuroendocrine and temperature effects of nefazodone in healthy volunteers

The effects of a novel antidepressant, nefazodone (50 mg, 100 mg, and 200 mg orally) on neuroendocrine function and temperature were assessed using a single-blind, crossover design in eight healthy male volunteers. Nefazodone significantly increased plasma levels of prolactin (PRL) and raised oral temperature. There was also a trend towards an increase in plasma cortisol. These results are consistent with an acute facilitatory effect of some aspects of 5-HT neurotransmission, perhaps mediated through nefazodone's metabolism to its major metabolite, m-chlorophenylpiperazine (mCPP).

Neuroendocrine probes of serotonergic function: a critical review

Neuroendocrine probes of serotonergic function are based on the premise that serotonin (5-HT) exhibits an excitory influence on the release of certain anterior pituitary hormones and that the extent of release of these hormones following a challenge with a 5-HT agonist would provide an index of central 5-HT activity. This paper critically reviews studies published to date on healthy volunteers to assess the validity of tests of serotonergic function. Using standardized criteria, it is concluded that although extensive data is available on 5-HT-neuroendocrine probes, there is no test that is currently available that would fulfil all the proposed requirements for a test to be acceptable, although ipsapirone, m-chlorophenylpiperazine (m-CPP), and possibly fenfluramine challenge tests come very close. The rapid development and availability of more specific and stereo-selective 5-HT agonists/antagonists seem to indicate that it will not be too long before a valid neuroendocrine test for the assessment of serotonergic function emerges.

ECT treatment does not enhance neuroendocrine responses to serotonergic challenge

We prospectively investigated the effects of a course of electroconvulsive therapy (ECT) on neuroendocrine responses to serotonergic challenge in five depressed patients. Low dose intravenous chlorimipramine (CMI) challenge produced a modest release of prolactin and significant increases in plasma adrenocorticotrophic hormone (ACTH) and cortisol. Interestingly, ECT did not alter the neuroendocrine responses to serotonergic challenge despite clinical response in four of the five patients. If anything, the modest prolactin (PRL) response to CMI, rather than being enhanced, appeared to be abolished following ECT. Using confidence intervals, we estimate that there is less than a 5% probability of a 78% increase in prolactin response to CMI after ECT. To detect this, a sample size of greater than 35 would be needed. These findings suggest that neither ECT nor the clinical response in severely depressed patients is likely to produce consistent changes in neuroendocrine response to the acute serotonergic effects of CMI infusion. The lack of effect of ECT on prolactin response to serotonergic challenge might be explained by simultaneous enhancement of both serotonergic and dopaminergic neurotransmission.

Kinetic effects of desmethylimipramine treatment on platelet serotonin uptake in depressed patients: a comparison with imipramine

The kinetic effects of desmethylimipramine (DMI) on platelet serotonin (5HT) uptake were compared to those of imipramine (IMI) in eight DMI-treated depressed patients and seven IMI-treated depressed patients, and compared to values after patients were off drug for 19 (+/- 8 SD) and 33 (+/- 15) days. As expected, IMI was a stronger inhibitor of 5HT uptake than DMI during treatment, with the mean apparent Km in treated patients being elevated nearly threefold over that of the drug-free condition. In DMI-treated patients, the mean Km was elevated nearly twofold over that of the drug-free condition. Although DMI is considered a preferential norepinephrine uptake inhibitor, the results suggest the following: (1) Significant decreases in the apparent platelet 5HT affinity are achieved with DMI; (2) the inhibition kinetics in depressed patients are competitive; (3) there was a significant relationship between Km change and depression outcome with DMI discontinuation; and (4) DMI, as a metabolite, appears to contribute to the 5HT uptake inhibition of IMI in vivo.

Prolactin in childhood obsessive-compulsive disorder: clinical correlates and response to clomipramine

Basal prolactin concentrations were measured before treatment in 18 children and adolescents with obsessive-compulsive disorder as well as in 15 of these patients after 4 and 8 weeks of clomipramine treatment. Basal prolactin levels were influenced by a history of chronic tic disorder and by the duration and severity of obsessive-compulsive symptoms. Clomipramine administration significantly increased basal prolactin levels. A slight decline in prolactin levels during the last 4 weeks of clomipramine treatment was positively correlated with a favorable treatment response and negatively correlated with duration of illness. If the changes in prolactin levels observed during clomipramine treatment are due primarily to changes in serotonergic neurotransmission, these data suggest that clomipramine treatment of obsessive-compulsive disorder produces an adaptive decrease in the responsiveness of serotonergic receptors.

Immediate effects of intravenous clomipramine on sleep and sleep-related secretion in depressed patients

An i.v. challenge dose of clomipramine (12.5 mg) was given to eight outpatients with major depression. The procedure facilitated the examination of all-night sleep and sleep-related neuroendocrine changes (cortisol, growth hormone, and prolactin). In comparison to baseline saline nights, the patients experienced a profound suppression of rapid eye movement (REM) sleep throughout the night with no rebound recovery in the second half of the night. Furthermore, REM-suppressing effects were noted on the following no-drug night. In contrast, little effect on delta wave sleep was found, except for increased consolidation of delta waves within stage 3 and 4 sleep. Delta sleep measures were significantly correlated with levels of cortisol and growth hormone.

Acute effect of intravenous clomipramine upon sleep-related hormone secretion in depressed outpatients and healthy control subjects

Tricyclic antidepressants have been used frequently as pharmacological probes in neuroendocrine studies even though they appear to lack neurochemical specificity. Despite this, the hormonal responses to these drugs have been used to provide evidence that depressed patients have alterations in both noradrenergic and serotonergic tone within the central nervous system. Most studies have been conducted in the morning, which is not a time of high physiological neuroendocrine secretory activity. The present study has used the relatively specific serotonergic probe intravenous clomipramine given to depressed patients and healthy subjects immediately before sleep onset, which is a time of increased neuroendocrine activity. Under these conditions, 12.5 mg clomipramine stimulates the secretion of both cortisol and prolactin, but unlike studies conducted in the morning, clomipramine suppresses the secretion of growth hormone in both groups. These data suggest that serotonergic mechanisms are involved in the regulation of the secretion of these three hormones at the time of sleep onset.

Differential effect of clomipramine treatment on m-chlorophenylpiperazine-induced increases in plasma prolactin and corticosterone in rats

Intravenous administration of m-chlorophenylpiperazine (m-CPP, a serotonin agonist) to rats increased plasma prolactin and corticosterone concentrations. Long-term (21-day) and short-term (3-day) treatment with the tricyclic antidepressant, clomipramine, did not have any significant effect on baseline levels of either prolactin or corticosterone. Long-term but not short-term clomipramine treatment significantly potentiated m-CPP's effect on plasma prolactin. On the other hand, both long-term and short-term clomipramine treatment significantly attenuated m-CPP's effect on plasma corticosterone. These findings are consistent with other animal and clinical studies demonstrating a differential effect of antidepressant treatment on two different serotonin-mediated neuroendocrine functions.

Desipramine increases circulating growth hormone in elderly depressed patients: a pilot study

Serial blood samples were collected from 15 elderly depressed inpatients, ages 62 to 95 years, following random assignment to a 50 mg oral test dose of desmethylimipramine (DMI) or amitriptyline (AMI). Nine female and six male subjects began the 210-min study at 0800h. Serum growth hormone (hGH), cortisol, and prolactin (hPRL) were determined by radioimmunoassay. Baseline hormone concentrations were related to self and observer ratings of anxiety and depression. There was a trend for the hGH, cortisol, and hPRL concentrations to decline during the period of study. This trend for all three hormones reversed in those subjects receiving DMI, beginning approximately 90 min after drug ingestion. The DMI-induced increase of hGH reached statistical significance at the very end of the sampling period. There was an apparent latency in the DMI-induced effect for all three hormones. There was no stimulatory effect of AMI on hGH, cortisol, or hPRL. The female subjects had higher baseline hGH levels than the men. In addition, a significant negative correlation was found between baseline hPRL levels and self ratings of anxiety.

Lithium increases 5-HT-mediated prolactin release

The effects of short-term (3-4 days) lithium treatment on the prolactin responses to intravenous clomipramine (0.1 mg/kg), metoclopramide (5 micrograms/kg) and haloperidol (2.5-5 micrograms/kg) were assessed in male volunteers. Prolactin responses to clomipramine were significantly enhanced by lithium while those following administration of haloperidol and metoclopramide were not significantly altered. Lithium did not change the cortisol response to clomipramine. The results suggest that lithium may selectively enhance 5-HT mediated prolactin release. These data are consistent with the hypothesis that synergistic effects of lithium and clomipramine on brain 5-HT function may be involved in their therapeutic effect in resistant depression.

Growth hormone response to desmethylimipramine in depressed and suicidal adolescents

Desipramine 75 mg i.m. was given in the morning to 20 adolescents with major depressive disorder and 23 normal controls. Depressed adolescents secreted significantly less growth hormone (GH) over the next 2 h than did normal adolescents, although a substantial proportion of the differences were accounted for by the depressed adolescents who had a specific suicidal plan or attempt during the episode. Severity of depression or the presence of other depressive symptoms did not predict GH secretion within the depressed group. Age, sex and maturational factors in the control of GH are discussed. It is concluded that these differences in GH secretion probably reflect differences in CNS beta-adrenergic and/or serotonergic function. Suicidality and depression may have different psychobiological correlates in adolescents.

Prolactin in patients with major depressive disorder and in healthy subjects. II. Longitudinal study of basal prolactin and post-TRH-stimulated prolactin levels

Longitudinal investigations of basal prolactin (PRL) and prolactin concentrations following thyrotopin-releasing hormone (TRH) stimulation (delta PRL) were conducted in 17 patients with major depressive disorder and healthy subjects. The patients were being treated with either clomipramine or maprotiline. Both basal and delta PRL increased significantly after clinical response during treatment with both drugs. However, these increases in basal and delta PRL were independent of each other. Surprisingly, elevations of basal PRL were significantly greater in responders than in nonresponders, whereas those in delta PRL showed no corresponding significant difference. These results suggest that the two drugs stimulate basal and delta PRL by different mechanisms. The increases in basal prolactin levels found in responders may possibly be due to weaker inhibition of prolactin due to "down-regulated" beta adrenergic receptors and/or enhanced activity of supersensitive serotonergic receptors. Neither basal PRL nor delta PRL proved to be a predictor of therapy response. The intraindividual retest reliabilities of both basal and delta PRL in healthy subjects was so good that a single blood sample would seem to be sufficient for investigating most issues involving PRL in psychiatric patients.

Clomipramine in obsessive-compulsive ritualisers treated with exposure therapy: relations between dose, plasma levels, outcome and side effects

Forty-nine obsessive-compulsive ritualisers completed a double-blind controlled study of clomipramine and exposure therapy. More severely ill patients allowed higher doses of medication to be prescribed and had higher plasma levels of both clomipramine and desmethylclomipramine. Exposure instructions had a strong effect, whereas the clomipramine effect was small and short-lived. Plasma levels of desmethylclomipramine but not of clomipramine correlated with outcome at weeks 8 and 17. There was no evidence of a therapeutic window for either clomipramine or its metabolite. Patients' physical complaints before treatment correlated positively with depression and anxiety, especially sexual difficulties. Dry mouth, as a side effect, was most evidently related to clomipramine and its usefulness in monitoring drug compliance for patients on clomipramine is reaffirmed.

Effects of desipramine and total sleep deprivation on hormonal levels of healthy subjects

Plasma prolactin (PRL) and growth hormone (GH) were serially measured over a 5-hour morning period in healthy subjects who twice received a single oral dose of 100 mg desipramine (DMI). The study was carried out both after a regular night of sleep and after 1 night of total sleep deprivation. Clinical studies have suggested that sleep deprivation could potentiate the therapeutic effects of antidepressants, and there were reports on DMI stimulation of GH. The basal PRL levels decreased after sleep deprivation, but subsequently increased after DMI, whereas the same dose of DMI did not affect PRL in the absence of after DMI, whereas the same dose of DMI did not affect PRL in the absence of sleep deprivation. The GH levels increased substantially (8- to 10-fold) after DMI in both experimental conditions. Sleep deprivation neither changed GH basal levels nor potentiated the DMI-induced GH increase.

The neuroendocrine effects of oral imipramine

The release of growth hormone, prolactin and cortisol following oral imipramine was studied in nine fit young men. Imipramine 100 mg, but not 40 mg, led to reliable rises in the circulating levels of all three hormones in the majority of subjects. These responses are likely due to the enhancement of central noradrenergic and serotonergic function as a result of reuptake inhibition. The safety, sensitivity and reliability of these responses make imipramine 100 mg orally a potentially valuable neuroendocrine challenge test.

Effect of chlorimipramine and maprotiline on experimental anxiety in humans

In order to assess the role played by serotonin (5-HT) and noradrenaline in anxiety, four groups of healthy volunteers were given 25 mg of the selective inhibitor of 5-HT uptake chlorimipramine, 50 mg of the selective inhibitor of noradrenaline uptake maprotiline, 1 mg of the benzodiazepine anxiolytic lorazepam or placebo, and submitted to a simulated public speaking (SPS) test, consisting of speaking in front of a videocamera. Subjective anxiety was evaluated by the visual analog mood scale (VAMS) of Norris as well as by the state-trait anxiety inventory (STAI) of Spielberger. Chlorimipramine enhanced SPS-induced anxiety, whereas maprotiline and lorazepam reduced anxiety during as well as outside the test period. Mental and physical sedation (VAMS) were increased by either maprotiline or lorazepam. In a scale of bodily symptoms, chlorimipramine tended to increase muscle tension, agitation and palpitation, whereas maprotiline caused lethargy. The rise in blood pressure induced by the SPS procedure outlasted the period of stress in the group treated with chlorimipramine. In contrast, the SPS-induced increase in heart rate was enhanced by lorazepam. Chlor imipramine and maprotiline reduced salivation to the same extent. Pupillary diameter, however, was significantly increased by chlorimipramine alone. It may be tentatively sug gested that the proanxiogenic effect of chlorimipramine is related to changes in central 5-HT neurotransmission while the anxiolytic effect of maprotiline is associated with alteration of noradrenergic mechanisms. Increased peripheral sympathetic tone may also contribute to the proanxiety action of chlorimipramine.

Does alprazolam, in contrast to diazepam, activate alpha 2-adrenoceptors involved in the regulation of rat growth hormone secretion?

The conventional benzodiazepine diazepam and the novel triazolobenzodiazepine alprazolam were compared with respect to effects on growth hormone (GH) release in reserpine pretreated rats. The reserpine pretreatment was undertaken to eliminate brain monoaminergic influence on GH secretion, hence obtaining a low GH baseline from which a drug induced increase could be easily detected. Previous studies have indicated that activation of brain alpha 2-adrenoceptors is an indispensable prerequisite for GH release induced by other agents such as serotonin and opiate receptor agonists. In line with these findings, diazepam was found to induce GH release in reserpine pretreated rats only when the alpha 2-receptor agonist clonidine was simultaneously administered. In contrast, alprazolam caused a dose-dependent increase in plasma GH when given alone to reserpine pretreated rats. This effect of alprazolam was effectively antagonized by either of the two selective alpha 2-receptor antagonists yohimbine or idazoxane. The data indicate that alprazolam, but not diazepam, activates brain alpha 2-adrenoceptors involved in rat GH regulation. The possibility that an alpha 2-agonistic profile of alprazolam may contribute to the suggested effectiveness of the drug in the treatment of panic disorder is discussed.

Effects of receptor blockers (methysergide, propranolol, phentolamine, yohimbine and prazosin) on desimipramine-induced pituitary hormone stimulation in humans--II. Prolactin

In this report the effects of various receptor blockers on desimipramine (DMI)-induced prolactin (PRL) secretion in healthy male subjects are presented. Each trial consisted of two administrations: one of DMI i.v. alone and one of DMI i.v. in combination with the respective receptor blocker: methysergide (serotonin (5-HT) receptor blocker), propranolol (beta receptor blocker), phentolamine (alpha-1/alpha-2 receptor blocker), yohimbine (alpha-2 greater than alpha-1 receptor blocker), and prazosin (alpha-1 receptor blocker). Following administration of methysergide (12 mg p.o., n = 12), a significantly lower (p less than 0.01) DMI-induced PRL secretion compared to DMI alone in another group of subjects (n = 12) was observed. Combined administration with propranolol (15 mg i.v.) significantly enhanced the DMI-induced PRL secretion compared to DMI 50 mg i.v. alone (n = 18, incomplete block design) (p less than 0.01). Neither combined administration with phentolamine (60 mg i.v., n = 12), yohimbine (10 mg i.v., n = 6), nor prazosin (1 mg p.o., n = 12) significantly influenced the DMI-induced PRL secretion compared to DMI alone in the same subjects. The results of the present study, especially the inhibitory effect on DMI-induced PRL secretion of methysergide, indicate that the primarily noradrenaline (NA) and lesser serotonin (5-HT) reuptake inhibiting antidepressant DMI stimulates PRL secretion via 5-HT neurons. Furthermore, the significantly enhanced PRL release following combined administration of DMI and propranolol suggests that a noradrenergic inhibitory effect also may be involved in the transmission of the PRL stimulus.

Dose-dependent growth hormone, prolactin and cortisol stimulation after i.v. administration of desimipramine in human subjects

In previous studies it was shown that the tricyclic antidepressant desimipramine (DMI) had different stimulatory effects on growth hormone (GH), prolactin (PRL), ACTH and cortisol secretion in healthy subjects, depending on the mode of administration. The present study examined the effects following i.v. administration of placebo and DMI (5, 15, 25, 50 and 75 mg) on GH, PRL and cortisol secretion in male subjects (n = 6). This primarily noradrenergic and secondarily serotonergic reuptake-inhibiting substance was found to stimulate the secretion of GH, PRL and cortisol in a dose-dependent manner. Compared to placebo, significant increases occurred in GH (p less than 0.05) and in PRL (p less than 0.05) from a dose of DMI 25 mg on, and in cortisol (p less than 0.05) from 15 mg on. The results indicate that, in addition to the dose, the method of administration influenced the effects of DMI on the three hormones.

Hormonal responses to zimelidine and desipramine in depressed patients

Plasma prolactin (PRL), growth hormone (GH), luteinizing hormone (LH), and cortisol were repeatedly measured during the morning over a 4-hour period in patients who received single or chronic doses of desipramine (DMI) or zimelidine (ZIM). Preclinical studies had suggested that DMI, an uptake inhibitor specific for norepinephrine, would have different effects than ZIM, a selective serotinin uptake inhibitor. The GH response to DMI was blunted in the depressed patients. Neither DMI nor ZIM produced changes in LH or cortisol. DMI acutely increased plasma PRL, whereas ZIM had an effect only after chronic pretreatment. Chronic DMI but not ZIM increased baseline PRL. The patterns and magnitude of responses raise questions concerning the role of serotonin and norepinephrine in PRL release in man and the applicability of current preclinical models.