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Journal Article 2007; 28(5): 585-590 PubMed PMID: 17984949 Citation  Keywords:  Adaptation, Psychological:physiology, Aggression:physiology, Animals, Corticosterone:blood, Dominance-Subordination, Hypothalamo-Hypophyseal System:physiology, Male, Mice, Mice, Inbred BALB C, Social Environment, Stress, Psychological:blood, Territorialit.   

OBJECTIVE: Social stressors modulate the hypothalamic-pituitary-adrenal axis in rodents. However, reports on the association between corticosterone level and behavioural responses to the stressor are ambivalent. This may depend on the experimental paradigm, species- and strain-differences, duration of exposure to the stressor, but also on using either the social state (dominant or subordinate) or the coping style (proactive or passive) of an animal to correlate the corticosterone level with.

DESIGN AND SETTING: We used male Balb-C mice in a resident-intruder paradigm. Adolescent intruders (aged five to eight weeks) were transferred into the cage of an adult resident (aged about four month) for five minutes. The interactions were video-taped for behavioural analysis. Ten minutes after the encounters, intruders were sacrificed and blood samples were collected.

RESULTS: Dominant intruders showed offensive behaviours (attack, chase, tail tracking) and won most of the fights, whereas subordinate intrudes showed mainly submissive behaviours (flight, freezing) and were further classified into active and passive subordinates. Active subordinates displayed significantly more flight-behaviour than passive subordinates. Dominant intruders showed significantly higher post-stress levels of corticosterone than subordinates, which did not differ from control mice, which experienced five minutes of novel-cage exposure. Comparing all three behavioural phenotypes we found the lowest corticosterone levels in active subordinates.

CONCLUSION: Social state significantly affects the HPA-axis response to acute social stressors....

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Journal Article 2007; 28(5): 639-642 PubMed PMID: 17984948 Citation  Keywords:  Adaptation, Psychological, Adult, Depressive Disorder:blood, Dissociative Disorders:blood, Female, Humans, Hypothalamo-Hypophyseal System:physiopathology, Male, Middle Aged, Pituitary-Adrenal System:physiopathology, Prolactin:blood, Statistics, Nonparamet.   

OBJECTIVES: Usual neuroendocrinological manifestation of traumatic stress and dissociation is dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. The aim of the present study is to perform examination of HPA axis as indexed by basal serum prolactin and test its relationship to dissociative symptoms and symptoms of traumatic stress.

PATIENTS AND METHODS: 25 inpatients treated at the university hospital with diagnosis of unipolar depression mean age 41.23 (SD=11.53) were assessed using psychometric measures of dissociation (DES) and traumatic symptoms (TSC-40), and using standard biochemical analytical methods basal serum prolactin levels were investigated.

RESULTS: Data show that prolactin manifests significant relationship to dissociative symptoms (r=0.52, p=0.004). Significant correlation was not found between prolactin and traumatic symptoms measured by TSC-40 (r=0.31, p=0.07).

CONCLUSIONS: The present data suggest that serum prolactin levels in unipolar depressive patients are related to dissociative symptoms that is likely caused by passive coping mechanisms leading to dissociation....

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Comparative Study 2006; 27(3): 369-372 PubMed PMID: 16816828 Citation  Keywords:  Adaptation, Physiological:drug effects, Analysis of Variance, Animals, Cholesterol:metabolism, Cold Temperature, Female, Hot Temperature, Kidney:metabolism, Lipid Metabolism:drug effects, Lipids:blood, Liver:metabolism, Male, Mice, Muscarinic Antagonists:.   

OBJECTIVES: The effect of scopolamine administration at dose 0,5 g/kg b.w. and high (+40 degrees C) and low (+4 degrees C) temperature on the level of triacyloglycerides, total lipids and cholesterol in the mouse liver, kidney and muscle of males and females.

METHODS: The homogenates of the liver, kidney and muscle were taken for examination. The concentrations of triacyloglycerides, total lipids and cholesterol was estimated according to the Bio-La-Tests (Poland).

RESULTS: The concentration of triacyloglycerides and total lipids in the liver, kidney and muscle increased of males and females after scopolamine injections and after exposure to high and low temperatures.

CONCLUSION: Scopolamine may effect an increase in the rate of the lipid metabolism....

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Comparative Study 2005; 26(6): 719-723 PubMed PMID: 16380689 Citation  Keywords:  Adaptation, Physiological, Adrenal Glands:enzymology, Animals, Electron Transport Complex IV:biosynthesis, Enzyme Induction:drug effects, Hypothalamo-Hypophyseal System:physiopathology, Liver Circulation:drug effects, Liver Cirrhosis, Experimental:chemica.   

OBJECTIVES: Cytochrome oxidase activity has been determined in the adrenal glands of thioacetamide (TAA)-cirrhotic rats.

MATERIAL AND METHODS: Two groups of animals (Control group; n=10 and TAA group; n=11) of three months evolution were used to study the cytochrome oxidase activity in the suprarenal cortex (glomerular, fascicular and reticular layers) and medulla. TAA was administered orally and cytochrome oxidase (COX) activity was assayed by an immunohistochemical technique.

RESULTS: In TAA-cirrhotic rats, COX activity increases in the cortex fascicular layer (221 +/- 1.79 vs 181.9 +/- 2.75; p<0.001) as well as in the medulla (146.6 +/- 1.72 vs 129 +/- 3.09; p<0.001).

CONCLUSION: These results make it possible to consider the existence of hypothalamic-pituitary-adrenal-axis and adrenomedullary sympathetic system hyperactivity, both peripheral limbs of the stress system, in this experimental model of cirrhosis....

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Clinical Trial 2005; 26(6): 771-774 PubMed PMID: 16380685 Citation  Keywords:  Adaptation, Psychological, Adolescent, Adult, Analysis of Variance, Cultural Evolution, Female, Hierarchy, Social, Homosexuality, Humans, Male, Psychological Theory, Reproduction, Sex Factors, Sexual Behavior:psychology, Social Behavior,.   

OBJECTIVES: The alliance theory holds that homosexual behavior in humans may have evolved because it reinforced same-sex alliances which contributed to survival and reproduction. The present study was designed to test this evolutionary hypothesis in view of the strongly negative perception of homosexual behavior. It was predicted that targets who engaged in homosexual behavior would be perceived as likely to achieve greater social status and reproductive opportunities when the behavior reinforced an alliance that led to increased social opportunities.

METHODS: Three hundred sixteen men and women read scenarios in which a target engaged in homosexual behavior and then answered questions about the target's future social status and reproductive opportunities as measured by number of sexual partners. The data were analyzed in two 3 (social outcome: positive vs. neutral vs. negative) x 2 (gender of target) x 2 (gender of participant) analyses of variance.

RESULTS: The results supported the predictions and demonstrated that targets were perceived as likely to have the greatest social status and reproductive opportunities in the positive outcome condition.

CONCLUSION: The alliance theory of homosexual behavior may have heuristic value for the evolutionary study of homosexual behavior and its perception....

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Journal Article 2005; 26(4): 355-360 PubMed PMID: 16136009 Citation  Keywords:  Adaptation, Psychological, Adult, Aggression:physiology, Female, Hostility, Humans, Male, Middle Aged, Personality:physiology, Reference Values, Stress, Psychological:blood, Testosterone:blood,.   

OBJECTIVES: Many studies assessing the role of sex hormones, like testosterone, on stress and hostility factors have been primarily conducted in selected atypical populations such as violent criminals as well as androgen users and abusers. Therefore, the main aim of the current study was to investigate the association between testosterone levels and two psychosocial variables: stress and hostility in a cohort of healthy individuals who were members of a health maintenance organization (HMO).

METHODS: At five quarterly visits, psychosocial scales and blood draws were collected. Psychological stress was measured by using several scales that assessed different types of stress, including daily hassles, major life events and perceived stress. Similarly, different aspects of hostility were measured, among them cynicism, hostile affect and aggressive responding. Plasma collected from each visit was used for testosterone level determinations.

RESULTS: Testosterone levels were significantly associated with stress in both males and females. However, whereas this association exhibited a "threshold effect" in males, it demonstrated a direct and continuous linear relationship between these variables in females. Hostility was not correlated with testosterone levels in neither males nor females.

CONCLUSIONS: These results suggest that testosterone levels in normal males and females may be more reflective of an intricate balance between physiological responding and emotional coping to stressors than the hostility profile of the individual....

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Comparative Study 2004; 25(1-2): 102-108 PubMed PMID: 15159692 Citation  Keywords:  Adaptation, Physiological, Animals, Circadian Rhythm:radiation effects, Darkness, Light, Male, Photoperiod, Photoreceptor Cells:radiation effects, Pineal Gland:radiation effects, Rats, Rats, Wistar,.   

OBJECTIVE: This study was aimed to examine the pineal gland of rats exposed to constant light and darkness at light and electron microscopic level.

DESIGN: For this purpose 18 male Wistar rats were used. Animals were divided into three groups. Rats in group I (Control) were kept under 12 hrs light: 12 hrs dark conditions. Rats in group II were exposed to constant darkness, while rats in group III were exposed to constant light for 6 weeks. At the end of the experiment, all animals were killed by decapitation. The pineal glands of rats were removed, then processed for light and electron microscopy.

RESULTS: In our study, extensive number of pinealocytes was observed in the structure of pineal gland of rats exposed to constant darkness and some of the observed pinealocytes were determined to contain double nucleoli. Furthermore, mitochondria and lipid droplets in the cytoplasm of pinealocytes were increased and rough endoplasmic reticulum sacs were enlarged in this group. Whereas, in rats those exposed to the constant light, a decrease in pinealocyte intensity was associated with increase in the connective tissue between parenchymal cells. Additionally, mitochondria and lipid droplets in the cytoplasm of cells were decreased.

CONCLUSIONS: It was observed that the pinealocyte cell activity of rats exposed to constant darkness was increased but decreased in rats exposed to constant light....

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Clinical Trial 2004; 25(1-2): 75-77 PubMed PMID: 15159687 Citation  Keywords:  Adaptation, Physiological, Adolescent, Adult, Altitude, Atmospheric Pressure, Fasting:blood, Humans, Jordan, Luteinizing Hormone:blood, Male, Reference Values, Religion, Testosterone:blood,.   

OBJECTIVES: To study a possible effect of Ramadan fasting on luteinizing hormone and testosterone in people of the Jordan Valley.

METHODS: A comparative study (n=40) of serum levels of luteinizing hormone (LH) and testosterone (T) between people living in the Jordan Valley (JV), n=20, 360 meters below sea level, and those living in Ramtha City (RC), n=20, 600 meters above sea level, was conducted in December, 1998. A similar study (n=40) was also done during January 1999 in fasting people during the month of Ramadan.

RESULTS: Serum levels of LH in non-fasting people of the JV were statistically similar to those in people of RC. There was also no difference in serum levels of T between non-fasting people of the JV and those in RC. Serum levels of LH in fasting people of the JV were statistically indifferent from those fasting in RC. Serum T levels in fasting people of the JV, on the other hand, were higher than those in fasting people of RC (76+/-18.3 ng/ml compared to 62.7+/-24.2 ng/ml).

CONCLUSIONS: It is probably the environmental factors such as the higher barometric pressure of the JV compared to that at above sea level that play a role in higher serum levels of T in people of the JV. Other factors, such as genetic background and/or the cultural and nutritional characteristics of the people of the JV, may also contribute to this difference in serum T levels....

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