ABSTRACT
In addition to the occurrence of pain, the evidence of a diminished capacity to feel pleasure is one of the most common cancer-related symptoms. Recent advances in psychoneuroendocrinological knowledge has shown that the perception of pleasure is mainly mediated by the dopaminergic pathways in the brain. Moreover, it has also been demonstrated that the brain dopaminergic sensitivity may be clinically explored by evaluating the endocrine response to the administration of dopaminergic agents, such as apomorphine, which consists of a decline in PRL concentrations and an increase in GH and cortisol levels. The present study was performed to evaluate dopaminergic sensitivity by the administration of apomorphine in cancer patients in an attempt to document possible cancer-related neuroendocrine anomalies, which could explain the psychological status of the patients. The study included 24 cancer patients (breast cancer: 12; colorectal cancer: 7; non-small cell lung cancer: 5), 12 of whom showed distant organ metastases. Apomorphine was given orally at 0.01 mg/kg b.w., by collecting venous blood samples before and after 20 and 60 minutes. A normal decline in PRL levels was seen in both non-metastatic and metastatic cancer patients. No cortisol increase in response to apomorphine was achieved and the lack of cortisol response was particularly evident in metastatic patients. No GH rise occurred in either metastatic or non-metastatic cancer patients. Finally, no significant difference in the endocrine response to apomorphine was seen in relation to the histotype of tumor. The results of this study show that the neoplastic disease is characterized by neurochemical alterations involving pleasure-related dopaminergic pathways, which are more evident in the metastatic disease, without particular differences in relation to tumor histotype. Therefore, the psychological condition of cancer patients would not depend only on psychological factors, but it could be due at least in part to cancer-related neuroendocrine alterations involving the dopaminergic system.
Subject(s)
Brain Chemistry/physiology , Breast Neoplasms/physiopathology , Breast Neoplasms/psychology , Colorectal Neoplasms/physiopathology , Colorectal Neoplasms/psychology , Dopamine/physiology , Adult , Aged , Breast Neoplasms/secondary , Carcinoma, Non-Small-Cell Lung/physiopathology , Carcinoma, Non-Small-Cell Lung/psychology , Carcinoma, Non-Small-Cell Lung/secondary , Colorectal Neoplasms/secondary , Female , Happiness , Human Growth Hormone/blood , Humans , Hydrocortisone/blood , Lung Neoplasms/physiopathology , Lung Neoplasms/psychology , Lung Neoplasms/secondary , Male , Middle Aged , Perception , Prolactin/bloodABSTRACT
OBJECTIVES: Recent studies have suggested the involvement of the pineal gland and its main hormone melatonin (MLT) in the pathogenesis of psychiatric disturbances, namely the depressive syndrome. In contrast, the behavior of MLT secretion in schizophrenia is still controversial. MATERIAL & METHODS: The present study was carried out to analyze light/dark rhythm of MLT secretion in relation to that of cortisol and prolactin (PRL) in schizophrenic patients. The study included 13 schizophrenic patients, 8 of whom were untreated, while the other 5 patients were on neuroleptic therapy. Serum levels of MLT, PRL and cortisol were measured by RIA on venous blood samples collected at 8 A.M., 12 A.M., 8 P.M. and 1 A.M. The control group consisted of 20 age-matched healthy subjects. RESULTS: A physiological nocturnal increase in MLT levels occurred in 6/13 patients, whereas the other 7 patients showed an abnormally low MLT peak during the night. Moreover, both light and night mean levels of MLT were significantly lower in patients than in controls. In addition, mean nocturnal levels of MLT were significantly lower in chronic patients than in those evaluated at the onset of disease. Cortisol rhythm was normal in 11/13 patients, whereas PRL levels were abnormally high in 10/13 patients. CONCLUSIONS: This preliminary study would suggest that schizophrenia may be associated with a diminished secretion of MLT from the pineal gland, and pineal deficiency would be more evident in the chronic disease. Finally, pineal alterations have appeared to be associated with an altered secretion of PRL and cortisol, by suggesting that the schizophrenic disease may be characterized by marked neuroendocrine disturbances, whose physio-pathological and prognostic significance needs to be established by successive clinical investigations.
