Biomedical subjects

A I Esquifino

Publications and source records attributed to A I Esquifino.

At least 19 recordsLinked to original sources

PubMed2006

Circadian rhythms of prolactin secretion in neonatal female rabbits after acute separation from their mothers.

Newborn rabbits (Oryctolagus cuniculus) are only nursed for 3-5 min every 24 h and show a circadian increase in activity in anticipation of nursing. The objective of this study was to determine, in neonatal female rabbits after acute separation from the doe for 48 h, the changes in 24-h rhythms of plasma prolactin and median eminence and anterior pituitary concentration of dopamine (DA) and serotonin (5HT). In addition, median eminence concentration of the excitatory amino acid transmitters glutamate (GLU) and aspartate (ASP) and of the inhibitory amino acid transmitters gamma-aminobutyric acid (GABA) and taurine (TAU) was measured. A significant 21% increase of circulating prolactin occurred in isolated pups. In controls pups, plasma prolactin levels showed two peaks, during the first half of the light phase and at the beginning of the scotophase, respectively. In the isolated pups, a phase advance of about 4 h occurred for the two prolactin peaks. Hemicircadian changes of median eminence DA were found in controls, whereas a single daily peak (at 17:00 h) was found in the separated pups. Plasma prolactin and median eminence DA correlated significantly and inversely in the control group only. Pituitary DA content exhibited a single peak in controls and a hemicircadian pattern in isolated pups. Plasma prolactin and pituitary DA correlated significantly in isolated pups only 00000. Pup isolation decreased median eminence 5HT levels, augmented pituitary 5HT levels and disrupted their 24 h rhythmicity. Circulating prolactin correlated inversely with median eminence 5HT and directly with adenohypophysial 5HT only in controls. Isolation of pups generally modified the 24 h pattern of median eminence excitatory and inhibitory amino acid content by causing a prominent decrease at the beginning of the light phase. The results indicate that circadian rhythmicity of prolactin secretory mechanisms in female rabbit pups is significantly affected by pup's isolation from the doe.

Animals↗

PubMed2006

Twenty-four hour rhythm of plasma prolactin in female rabbit pups. Correlation with hypothalamic and adenohypophysial dopamine, serotonin, gamma-aminobutyric acid and taurine content.

Lactation in the rabbit is a nocturnal activity, extremely short and regular, that can be a strong synchronizer for the development of circadian rhythmicity in the pups. In the present study, 24-h rhythmicity of plasma prolactin and median eminence and anterior pituitary content of dopamine (DA), serotonin (5HT), gamma-aminobutyric acid (GABA) and taurine were examined in 11 days old female pups kept under 16 h light:8 h dark photoperiods (lights on at 08:00 h). Groups of six to seven female rabbit pups were killed by decapitation at six different time points throughout a 24-h cycle, starting at 09:00 h. Plasma prolactin levels changed significantly throughout the day, showing two peaks, one at first half of rest span (at 13:00 h) and another one at the beginning of the scotophase (at 01:00 h), just preceding doe visit. Median eminence DA content changed in a bimodal way as a function of time of day, displaying two maxima, at the beginning of the rest span and of the activity phase. Median eminence DA and plasma prolactin correlated significantly in an inverse way. Two maxima in median eminence 5HT levels were found, about 4 h in advance to the prolactin peaks. Circulating prolactin correlated inversely with median eminence 5HT content and directly with adenohypophysial 5HT content. Median eminence GABA content reached its maximum at the beginning of the scotophase and correlated significantly with plasma prolactin concentration. A positive correlation between plasma prolactin and adenohypophysial taurine content was observed. These results show that the circadian rhythmicity in prolactin secretory mechanisms in female rabbit pups develops during the early neonatal life.

Aging↗

PubMed2005

Melatonin, immune function and aging.

Aging is associated with a decline in immune function (immunosenescence), a situation known to correlate with increased incidence of cancer, infectious and degenerative diseases. Innate, cellular and humoral immunity all exhibit increased deterioration with age. A decrease in functional competence of individual natural killer (NK) cells is found with advancing age. Macrophages and granulocytes show functional decline in aging as evidenced by their diminished phagocytic activity and impairment of superoxide generation. There is also marked shift in cytokine profile as age advances, e.g., CD3+ and CD4+ cells decline in number whereas CD8+ cells increase in elderly individuals. A decline in organ specific antibodies occurs causing reduced humoral responsiveness. Circulating melatonin decreases with age and in recent years much interest has been focused on its immunomodulatory effect. Melatonin stimulates the production of progenitor cells for granulocytes-macrophages. It also stimulates the production of NK cells and CD4+ cells and inhibits CD8+ cells. The production and release of various cytokines from NK cells and T-helper lymphocytes also are enhanced by melatonin. Melatonin presumably regulates immune function by acting on the immune-opioid network, by affecting G protein-cAMP signal pathway and by regulating intracellular glutathione levels. Melatonin has the potential therapeutic value to enhance immune function in aged individuals and in patients in an immunocompromised state.

Journal Article↗

PubMed2005

Oestrus synchronisation of rabbit does at early post-partum by doe-litter separation or ECG injection: Reproductive parameters and endocrine profiles.

Inseminating rabbit does at early post-partum, in combination with early weaning, can increase prolificacy (total kits born and still born per parturition) and decrease parturition intervals. Oestrus synchronisation increases fertility and prolificacy, while decreasing the number of inseminations required for gestation. However, little is known about the effectiveness of different oestrus synchronisation methods at early post-partum. In this study, does (n = 138) were artificially inseminated nine times (over a period of 1 year, kits weaned at 25 days), on day 4 post-partum after separation from the litter (for 48 or 24 h) or 48 h after 25 UI eCG injection. Plasma levels of prolactin and estradiol were also evaluated in a subsample of 12 multiparous lactating does per treatment, on days 2, 3 and 4 post-partum. The three treatments increased overall fertility of multiparous females compared to controls (which were not synchronised), but there were no differences among treatments in total kits born or stillborn. Does treated with eCG had a higher culling rate. The interval between parturitions and the number of inseminations required for gestation tended to decrease with increasing number of inseminations. In lactating does, there was an interaction between treatment and insemination order. Fertility decreased with increasing inseminations in eCG does but tended to increase above control values in the separated does until the fourth insemination. Control lactating does had significantly less kits per parturition compared to treatments, but eCG lactating does had more stillborn kits. Oestradiol levels increased on day 4 post-partum in all synchronised lactating does (and immediately before artificial insemination in 48 h doe-litter separation), so ovarian activity could be stimulated at early post-partum using all treatments. However, the increase could not be explained by prolactin levels, since there were no effects of suckling absence on plasma prolactin in separated does. In conclusion, separating does from the litter before insemination can be just as effective as eCG treatment, especially during for the first four inseminations.

Animals↗

PubMed2005

Toxic effects of cadmium on the regulatory mechanism of dopamine and serotonin on prolactin secretion in adult male rats.

This work was designed to analyze the effects of cadmium on the regulatory mechanism of prolactin in cadmium-exposed rats. Adult male rats were given cadmium at a dose of 25 ppm of cadmium chloride (CdCl2) in the drinking water for 1 month. At the end of the treatment, the rats were killed at six different time intervals throughout a 24 h cycle to measure circulating prolactin levels and dopamine and serotonin content in the median eminence and in both anterior and posterior pituitary. Control and cadmium-exposed animals exhibited significant time of day-dependent variations in plasma prolactin levels and in dopamine and serotonin concentration in all analyzed tissue. Cadmium exposure did not modify the mean values of the hormone around the clock but it modified the amplitude of the secretory peaks at 08:00 and 12:00 h. Cadmium decreased dopamine content in the median eminence, while increased its content in the posterior pituitary and induced a phase advanced peak at 20:00 h. On the other hand, serotonin content was not modified in the median eminence. Only differences in specific time points were observed, while serotonin concentration in anterior and posterior pituitary were increased in cadmium-treated rats. Differences in time peaks were also observed. The negative correlation between plasma prolactin and dopamine content in pituitary, and between plasma levels of the hormone and serotonin content in posterior pituitary, disappeared in cadmium-treated animals.

Animals↗

PubMed2005

Role of melatonin in neurodegenerative diseases.

The pineal product melatonin has remarkable antioxidant properties. It scavenges hydroxyl, carbonate and various organic radicals, peroxynitrite and other reactive nitrogen species. Melatonyl radicals formed by scavenging combine with and, thereby, detoxify superoxide anions in processes terminating the radical reaction chains. Melatonin also enhances the antioxidant potential of the cell by stimulating the synthesis of antioxidant enzymes like superoxide dismutase, glutathione peroxidase and glutathione reductase, and by augmenting glutathione levels. The decline in melatonin production in aged individuals has been suggested as one of the primary contributing factors for the development of age-associated neurodegenerative diseases, e.g., Alzheimer's disease. Melatonin has been shown to be effective in arresting neurodegenerative phenomena seen in experimental models of Alzheimer's disease, Parkinsonism and ischemic stroke. Melatonin preserves mitochondrial homeostasis, reduces free radical generation, e.g., by enhancing mitochondrial glutathione levels, and safeguards proton potential and ATP synthesis by stimulating complex I and IV activities. Therapeutic trials with melatonin have been effective in slowing the progression of Alzheimer's disease but not of Parkinson's disease. Melatonin's efficacy in combating free radical damage in the brain suggests that it may be a valuable therapeutic agent in the treatment of cerebral edema after traumatic brain injury.

Aging↗

PubMed2005

Toxic effects of cadmium on GABA and taurine content in different brain areas of adult male rats.

This work assesses the possible changes in gamma amino butyric acid (GABA) and taurine content in the hypothalamus, the median eminence and striatum after the exposure to various doses of cadmium. Cadmium chloride (CdCl2) was administered in the drinking water at the doses of 5, 10, 25, 50 or 100 ppm to adult male rats for 1 month. In the anterior hypothalamus, taurine and GABA content decreased with the dose of 10 ppm of CdCl2 only. Cadmium exposure decreased both GABA and taurine content in mediobasal hypothalamus except for the 50 ppm dose. In posterior hypothalamus GABA and taurine content was not affected by cadmium treatment. As far as the median eminence, 5 or 10 ppm of CdCl2 increased taurine concentration, and at a dose of 5 ppm enhanced GABA content. A significant decrease of GABA and taurine concentration was seen in the striatum at any dose of cadmium used. The concentration of cadmium increased in the hypothalamus and in the striatum in animals receiving CdCl2 in the drinking water at doses of 25, 50 or 100 ppm. The results indicate that cadmium globally decreased GABA and taurine content in the brain areas studied through effects that were not dose dependent.

Animals↗

PubMed2004

Superior cervical ganglionectomy differentially modifies median eminence and anterior and mediobasal hypothalamic GABA content in male rats: effects of hyperprolactinemia.

This work was undertaken to analyze the changes in GABA concentrations in the anterior and mediobasal hypothalamus and in the median eminence after acute or chronic superior cervical ganglionectomy (SCGx), and whether high prolactin levels interfere with the effects of SCGx on GABA content. Acute but not chronic SCGx increased GABA content in all the areas studied, as compared to controls. The presence of a pituitary graft abolished the effects of acute SCGx in the median eminence and anterior hypothalamus, as compared to controls, but potentiated its effects in the mediobasal hypothalamus. Chronic SCGx increased GABA content in the mediobasal and anterior hypothalami, as compared to pituitary grafted controls. Acute SCGx decreased plasma prolactin and GH levels, but chronic surgery did not modify these hormone plasma levels. Acute SCGx increased plasma ACTH levels, whereas chronic SCGx did not modify them. Pituitary grafting increased circulating values of prolactin, ACTH and GH, as compared to controls. Acute SCGx did not modify plasma prolactin levels in grafted animals, although it increased plasma GH levels and decreased those of ACTH in this experimental group. Chronic SCGx further increased both plasma prolactin and GH levels, without modifying plasma ACTH levels. These results suggest that SCGx differentially modifies GABA content within the hypothalamus and median eminence. Induction of hyperprolactinemia in the neonatal age interferes with SCGx effects on both GABA content within the hypothalamus and median eminence and the secretory patterns of the pituitary hormones studied.

Animals↗

PubMed2004

Cadmium exposure differentially modifies the circadian patterns of norepinephrine at the median eminence and plasma LH, FSH and testosterone levels.

This work was designed to analyze the cadmium effects on time-of-day variations of norepinephrine (NE) content in median eminence and on plasma levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone in adult male rats. Rats were given cadmium at a dose of 25 ppm of cadmium chloride (CdCl(2)) in the drinking water for 1 month. Significant 24-h changes of NE content in the median eminence, plasma LH and testosterone levels occurred in control animals. Cadmium exposure induced a phase advance of the nocturnal peak of NE content that was described in the control group, to 12h and increased its amplitude. However, the mean NE content was not changed by cadmium. Metal exposure abolished the daily pattern of plasma LH levels, although the mean levels of the hormone were not modified by cadmium. For testosterone, the metal increased the amplitude of its nocturnal peak and induced the appearance of another peak during the light phase at 12h, thus increasing the mean plasma levels of this hormone. An interaction between the metal and time for NE and plasma testosterone levels was observed. These data suggest that cadmium exerts differential effects at the median eminence, the pituitary and the testes, that may explain the changes in the 24-h pattern of plasma testosterone levels.

Animals↗

PubMed2004

Experimental allergic encephalomyelitis in male Lewis rats subjected to calorie restriction.

This work analyzes the effect of calorie restriction on the development of experimental allergic encephalomyelitis (EAE) in Lewis rats. Plasma levels of ACTH, corticosterone, prolactin and growth hormone (GH) and mitogenic responses in submaxillary lymph nodes were measured. Male Lewis rats (6 weeks-old) were submitted to a calorie restriction equivalent to 66% of food restriction or to a normal diet. Fifteen days later, rats were injected with complete Freund's adjuvant plus spinal chord homogenate (SCH) or with complete Freund's adjuvant alone. Rats were monitored daily for clinical signs of EAE and were killed on day 15 after immunization. Only rats subjected to normal diet exhibited clinical signs of the disease. The increase in plasma ACTH and corticosterone found after SCH immunization in controls was not detectable in calorie restricted rats. Likewise, the correlation between circulating ACTH and corticosterone was no longer found after calorie restriction. Generally, calorie restriction by itself augmented plasma ACTH or corticosterone and this increase was not further amplified by SCH immunization. Only calorie restricted rats exhibited augmented plasma prolactin levels after SCH immunization, and decreased plasma GH levels regardless of immunization. Calorie restriction depressed the mitogenic response of lymphoid cells to concanavalin A but not to lipopolysaccharide. Calorie restricted rats did not exhibit augmented mitogenic response to concanavalin A following SCH immunization as those found in controls. The results are compatible with the view that the course of EAE can be significantly modified by caloric restriction.

Adrenocorticotropic Hormone↗

PubMed2004

Changes of prolactin regulatory mechanisms in aging: 24-h rhythms of serum prolactin and median eminence and adenohypophysial concentration of dopamine, serotonin, (gamma-aminobutyric acid, taurine and somatostatin in young and aged rats.

Twenty-four hour rhythmicity of serum prolactin and median eminence and anterior pituitary content of dopamine (DA), serotonin (5HT), gamma-aminobutyric acid (GABA), taurine and somatostatin were examined in 2 months-old and 18-20 months-old Wistar male rats. The concentration of prolactin was higher in aged rats, with peaks in both groups of rats at the early phase of the activity span. Median eminence DA content of young rats attained its maximum at the middle of rest span and decreased as prolactin levels augmented while the lowest values of adenohypophysial DA were observed at the time of prolactin peak. DA rhythmicity disappeared in aged rats. GABA content of median eminence and adenohypophysis was lower in aged rats, with maximal values of median eminence GABA at light-dark transition in young rats and at the second half of activity span in aged rats. Serum prolactin correlated positively with median eminence GABA in young rats and negatively with pituitary GABA in young and aged rats. Median eminence somatostatin peaked at the beginning of the activity phase (young rats) or at the end of the rest phase (aged rats). Prolactin levels and somatostatin content correlated significantly in young rats only. Median eminence and pituitary 5HT and taurine content did not change with age. The results indicate disruption of prolactin regulatory mechanisms with aging in rats.

Aging↗

PubMed2004

Differential effects of light/dark recombinant human prolactin administration on the submaxillary lymph nodes and spleen activity of adult male mice.

OBJECTIVES: Day/night variations in cellularity, percentage of CD4+, CD8+ and double-positive (CD4+-CD8+) lymphocytes, lipopolysaccharide (LPS)- and concanavalin A (Con A)-induced lymphocyte proliferation and natural killer (NK) activity, and the effect of timed administration of recombinant human prolactin (h-PRL) on the above-mentioned parameters were investigated in the submaxillary lymph nodes and spleen of adult male mice. RESULTS: In controls, the percentage of CD4+, double-positive lymphocytes, LPS- or Con A-induced blastogenic proliferation and NK activity in the spleen differ during the dark phase as compared to the light phase. When administered during the dark period, h-PRL induced immunosuppresion in the percentage of CD4+, double-positive (CD4+-CD8+) lymphocytes. Con A- and LPS-induced lymphocyte proliferation and NK activity as compared to untreated controls. When h-PRL was administered during the light period, the cellularity increased, and h-PRL was immunosuppressive in Con A- and LPS-induced lymphcoyte proliferation and NK activity as compared to controls. Moreover, in control submaxillary lymph nodes the cellularity, percentage of CD8+, double-positive lymphocytes, blastogenic proliferation in the presence of Con A and LPS and NK activity differ when comparing the dark with the light phase. When administered during the dark period h-PRL induced immunosuppression in the percentage of double-positive (CD4+-CD8+) lymphocytes, Con A- and LPS-induced lymphocyte proliferation as compared to controls. When h-PRL is administered during the light period, no effects were observed. CONCLUSIONS: These results indicate the existence of differential day/night variations in the cellular immune response depending upon the lymphoid organ considered. Because of the administration of h-PRL a differential modulation of this circadian variation was also observed.

Animals↗

PubMed2003

Effect of cadmium on 24-h variations in hypothalamic dopamine and serotonin metabolism in adult male rats.

This study was designed to analyze the possible cadmium effects on time-of-day variations of anterior, mediobasal, and posterior hypothalamic contents of dopamine (DA), serotonin (5-HT), and norepinephrine (NE) content in adult male rats. Also DA and 5-HT metabolism, as expressed by the ratio 3,4-dihydroxyphenyl acetic acid (DOPAC) to DA and 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT, respectively, were studied. Adult male rats were given cadmium at a dose of 25 ppm of cadmium chloride in drinking water for 1 month. Age-matched rats having access to cadmium-free water were used as controls. Weight gain for the whole period was not changed by cadmium exposure. The metal accumulated in the hypothalamus of rats. In the three hypothalamic regions, significant 24-h variations of NE and 5-HT concentration were found in controls, while DA content changed rhythmically in mediobasal hypothalamus only. Mean content of NE, 5-HT, and DA of anterior, mediobasal, and posterior hypothalamus decreased after cadmium exposure. After cadmium the 24-h pattern of NE changed only in mediobasal hypothalamus, whereas the metal changed significantly the pattern of 5-HT in all regions. DOPAC to DA and 5-HIAA to 5-HT ratios decreased and were differentially changed in all hypothalamic regions analyzed in cadmium-treated rats. There was a statistically significant relationship between time of administration of metal and time that the change took place in biogenic amines in the hypothalamus. These results indicate that cadmium may depress hypothalamic biogenic amine release.

Aging↗

PubMed2003

Effect of cadmium on lymphocyte subsets distribution in thymus and spleen.

This work was designed to analyze the possible dose dependent effects of cadmium on the distribution of lymphocyte subsets within the thymus and spleen. Cadmium accumulation was also evaluated in these tissues. For this purpose, adult male rats were exposed for one month to 0, 5, 10, 25, 50 or 100 ppm of cadmium chloride (CdCl2) in the drinking water. In both spleen and thymus, the B lymphocytes increased with the doses of 5 and 10 ppm of CdCl2, and decreased with the doses of 25-100 ppm. In spleen, the doses of 25 and 50 ppm decreased CD4+ cells and the doses of 5 and 10 ppm increased CD8+ cells, while the percentage of thymus T, CD4+, CD8+ and CD4(+)-CD8+ cells was not modified by cadmium treatment at any dose used in this study. After cadmium exposure, the metal was accumulated in the spleen only from the dose of 50 ppm on, and in the thymus, from the dose of 10 ppm on. In conclusion, although the accumulation of the metal is higher in thymus than in spleen, the metal affected CD4+ and CD8+ lymphocytes at the spleen but not at the thymus.

Animals↗

PubMed2002

Effects of overexpression of growth hormone on T cell activity in transgenic mice.

Growth hormone plays a key role in the maturation and maintenance of the immune response, however, the effects of chronic high circulating concentrations of the hormone on the immune system is poorly understood. Transgenic mice overexpressing bovine growth hormone (b-GH) gene, fused to the rat phosphoenolpyruvate carboxykinase promoter (PEPCK), with very high plasma concentration of heterologous b-GH and their littermate normal siblings were used. Spleen cellularity, percentages of total T lymphocytes, CD4+ and CD8+ cells, ratio of T cell subpopulations, mitogen-induced lymphocyte proliferation and natural killer (NK) cell activity were examined in male transgenic mice and normal littermate mice at 2 and 6 months of age. The number of splenic lymphocytes was greater in transgenic mice than in matched normal littermates at both ages. The NK cell activity was lower in transgenic mice than in the matched normal littermates at both ages, with the lowest values found in older mice. The b-GH transgenic mice had lower percentages of T cells at both ages, however, in young transgenic mice, the percentage of CD4+ cells was reduced while percentage of CD8+ cells was increased in comparison to normal controls. Both basal and mitogen-induced proliferation capacity of splenocytes were reduced in PEPCK-b-GH-25 mice as compared to normal littermates of both ages. Proliferative indexes in response to concanavalin A and phytohemagglutinin were markedly decreased in 6 month old PEPCK-b-GH-25 mice as compared to littermate controls or younger mice. These results indicate that overexpression of b-GH in mice is associated with decreased T cell function and that these abnormalities are age-dependent.

Age Factors↗

PubMed2002

Effects of oral cadmium exposure through puberty on plasma prolactin and gonadotropin levels and amino acid contents in various brain areas in pubertal male rats.

This work was undertaken to analyze if the effects of oral cadmium exposure through puberty, on plasma prolactin and gonadotropin levels are mediated by changes in amino acid contents in various brain areas in male rats. The contents of glutamate, glutamine, aspartate, GABA and taurine in the median eminence, anterior, mediobasal and posterior hypothalamus and prefrontal cortex in pubertal male rats exposed to 50 ppm of cadmium chloride (CdCl2) in the drinking waterfor 1 month (through puberty) were measured by high performance liquid chromatography (HPLC). Plasma prolactin, LH and FSH levels were measured by specific RIA methodology. Plasma prolactin levels decreased after cadmium exposure, whereas plasma levels of LH and FSH were not changed by the metal administration. After cadmium exposure, both glutamine and glutamate contents decreased in the median eminence and in anterior and posterior hypothalamus. Metal exposure also decreased aspartate content in anterior and posterior hypothalamus, but increased it in prefrontal cortex. GABA content decreased in any studied brain region after cadmium administration. Besides, the metal decreased taurine content in the median eminence, anterior and posterior hypothalamus and in prefrontal cortex. The results suggest that cadmium effects on plasma prolactin levels may be partially explained by the changes in aspartate, glutamate or taurine contents, but not by the decrease in GABA content in the brain regions studied.

Administration, Oral↗

PubMed2002

Possible role of glutamate, aspartate, glutamine, GABA or taurine on cadmium toxicity on the hypothalamic pituitary axis activity in adult male rats.

This work was designed to evaluate the possible changes in glutamate, aspartate, glutamine, GABA and taurine within various hypothalamic areas the striatum and prefrontal cortex after oral cadmium exposure in adult male rats, and if these changes are related to pituitary hormone secretion. The contents of glutamine, glutamate, aspartate, GABA and taurine in the median eminence, anterior, mediobasal and posterior hypothalamus, and in prefrontal cortex in adult male rats exposed to 272.7 micromol l(-1) of cadmium chloride (CdCl2) in the drinking water for one month. Cadmium diminished the content of glutamine, glutamate and aspartate in anterior hypothalamus as compared to the values found in the untreated group. Besides, there is a decrease in the content of glutamate, aspartate and taurine in the prefrontal cortex. The amino acids studied did not change in median eminence, mediobasal and posterior hypothalamus or the striatum by cadmium treatment. Plasma prolactin and LH levels decreased in rats exposed to the metal. These results suggest that (1) cadmium differentially affects amino acid content within the brain region studied and (2) the inhibitory effect of cadmium on prolactin and LH secretion may be partially explained by a decrease in the content of both glutamate and aspartate in anterior hypothalamus, but not through changes in GABA and taurine.

Administration, Oral↗

PubMed2002

Chronobiological features of the immune system. Effect of calorie restriction.

The circadian organization of living organisms is fully established being a key component the activity of the neuro-endocrin-immune system that maintains the homeostasis. Secondary lymph organs, such as submaxillary lymph nodes and spleen, have been shown to exhibit a 24 h variation in blastogenic proliferative capacity and distribution of B and T subsets, with specific achrophases depending on the parameter studied or the lymphoid organ considered. However, less is known about the thymus. The immune system has been shown to change by calorie restriction, although no information is available about possible effects in 24 h variations. Similar questions can be posed for the neuro-endocrine system. As an example, some data are shown in this article about the effects of calorie restriction on the neuro-endocrin-immune system in growing male Wistar rats. Calorie restriction blunted the circadian secretory pattern of TSH observed in the control group that was characterized by the existence of two peaks at 17:00 or 01:00 h and that explained the low basal metabolic rate of these animals under this experimental condition. Concerning the immune system, the thymus gland exhibited 24 h variations in T, B and immature cells in both control and calorie-restricted male rats, thus confirming the circadian organization of the immune system. Moreover this circadian organization was changed by calorie restriction.

Animals↗