Effect of Beta-Adrenergic Stimulation on the Circulatory Lymphocyte Count: Studies in Normals and in Patients with Chronic Airflow Obstruction

In eight non-allergic patients with chronic airflow obstruction (CAO) and eight age and sex matched, healthy control subjects the circadian variation in circulatory lymphocyte count was studied in relation to serum Cortisol and urinary epinephrine levels. In addition, we investigated the effect of the beta-adrenergic agent terbutaline on the lymphocyte count in two ways: as a long-term effect after 8 days of oral slow-release terbutaline with constant diurnal and nocturnal serum levels in patients, and as a short-term effect by a constant rate infusion of 0.2μg/min over 4hr in normals. Both patients and controls showed similar circadian patterns of urinary epinephrine excretion and lymphocyte counts. Patients with CAO, however, had significantly lower epinephrine levels and significantly higher lymphocyte counts at all hours of observation (every 4 hr from 0800 to 0800 hr the next day), as compared with normal controls. After 8 days of slow-release terbutaline the lymphocyte count in the patient group decreased to levels not significantly different from that of normals. The circadian rhythm of the lymphocytes, however, persisted under terbutaline therapy. No correlation existed between the lymphocyte count modulating factor, serum Cortisol and the lymphocyte count over 24 hr. On placebo infusion in the control persons an increase of lymphocytes over 4hr occurred, as a consequence of circadian rhythmicity. On terbutaline infusion a significant increase of lymphocytes after 1hr was follwed by a decrease to levels significantly below those on the placebo day. The same pattern was found in the leucocyte count. From this study it is concluded that beta-adrenergic stimulation corrects the relative lymphocytosis to counts comparable with normals. Other coinciding factors must regulate, however, the circadian rhythmicity.     

The Use of Salivary Steroids to Monitor Circadian Rhythmicity on Expeditions in the Arctic

The circadian variation in salivary Cortisol concentration was investigated in four men during a traverse on foot, of the Greenland ice cap and of salivary Cortisol and testosterone on a summer expedition to Spitzbergen. In both instances circadian rhythmicity was demonstrated both before leaving the U.K. and throughout the expedition. The acrophase of the rhythms followed the changes in activity patterns on both expeditions although there was a dissociation between the Cortisol and testosterone following an acute 8 hr phase shift in Spitzbergen. The mesor of Cortisol in both instances tended to be higher than in the U.K. but the difference was never statistically significant. This work demonstrates the feasibility of using salivary steroid concentrations to investigate their circadian rhythmicity in circumstances where frequent blood sampling would be precluded.     

Circadian Assessment of Lipids in the Hyperphagic Obese Rat Compared with Lean Litter-Mates

Time and feeding influences on cholesterol, triglyceride, glucose and insulin levels, and serum cholinesterase activity were assessed in a genetically-hyperlipidemic hyperphagic obese rat model, and compared with its lean litter-mate. Following a 28-day acclimation to a 12-hr light/dark cycle, blood samples were obtained every 2 hr from rats via tail bleed for a 24-hr period. Synchronization with other animal studies was established by endogenous serum Cortisol levels [acrophase 18–20 hr after light onset (HALO) in both groups]. Triglycerides cholesterol, insulin and glucose levels were significantly elevated in obese versus lean rats. Obese rats were observed to feed throughout the 24-hr cycle, whereas lean litter-mates ate only during the dark cycle. No circadian rhythmicity was found in glucose levels with either rat group. Insulin levels were not correlated. Although triglyceride levels peaks at 13 HALO in lean rats, no pattern was observed in obese rats. Cholesterol levels were unchanged with time in either group. Cholinesterase activity followed a circadian rhythm in the lean, but not obese, rats with an acrophase estimated at 8 HALO. In contrast to previous reports, enzyme activity was not correlated with triglyceride levels in either rat group. Circadian similarities in insulin levels between rat groups suggest changes in insulin metabolism and/or secretion which are likely to be independent of feeding or activity. Conversely, triglyceride levels remained elevated throughout the 24-hr period in obese rats, whereas significant increases were observed in lean rats during the dark active cycle. These data suggest that triglyceride levels, and not insulin and cholesterol levels, are most likely dependent on feeding patterns.     

Circadian Assessment of Lipids in the Hyperphagic Obese Rat Compared with Lean Litter-Mates

Time and feeding influences on cholesterol, triglyceride, glucose and insulin levels, and serum cholinesterase activity were assessed in a genetically-hyperlipidemic hyperphagic obese rat model, and compared with its lean litter-mate. Following a 28-day acclimation to a 12-hr light/dark cycle, blood samples were obtained every 2 hr from rats via tail bleed for a 24-hr period. Synchronization with other animal studies was established by endogenous serum Cortisol levels [acrophase 18-20 hr after light onset (HALO) in both groups]. Triglycerides cholesterol, insulin and glucose levels were significantly elevated in obese versus lean rats. Obese rats were observed to feed throughout the 24-hr cycle, whereas lean litter-mates ate only during the dark cycle. No circadian rhythmicity was found in glucose levels with either rat group. Insulin levels were not correlated. Although triglyceride levels peaks at 13 HALO in lean rats, no pattern was observed in obese rats. Cholesterol levels were unchanged with time in either group. Cholinesterase activity followed a circadian rhythm in the lean, but not obese, rats with an acrophase estimated at 8 HALO. In contrast to previous reports, enzyme activity was not correlated with triglyceride levels in either rat group. Circadian similarities in insulin levels between rat groups suggest changes in insulin metabolism and/or secretion which are likely to be independent of feeding or activity. Conversely, triglyceride levels remained elevated throughout the 24-hr period in obese rats, whereas significant increases were observed in lean rats during the dark active cycle. These data suggest that triglyceride levels, and not insulin and cholesterol levels, are most likely dependent on feeding patterns.     

Circadian Profile of Serum Melatonin in Cushing's Disease and Acromegaly

We evaluated the circadian profiles of serum melatonin (MT) and Cortisol in 6 patients with Cushing's disease while those of serum MT and GH were evaluated in 8 patients with acromegaly. The control group consisted of 15 healthy subjects in whom MT, Cortisol and GH were determined. The presence of a circadian rhythmicity was validated by the cosinor method, while the diurnal and nocturnal amount of MT secretion were expressed in terms of area under the curve. Gross alterations of MT rhythm were not apparent in Cushing's patients. In acromegalics, we observed a blunted day-night oscillation of MT accounted for by a significant increase of its secretion during the day-time period.     

Immunoneutralization of corticotropin-releasing hormone prevents the diurnal surge of ACTH

To determine whether CRH is required for the evening rise in plasma ACTH, rats were injected at 0800 hr with CRH antiserum (anti-CRH) or normal rabbit serum (NRS). Blood samples were taken through venous catheters at 0800 hr before treatment and at 1300, 1700, and 2100 hr. Plasma was assayed for immunoreactive ACTH and corticosterone. There was no significant difference in pretreatment values between the two groups. Immunoneutralization of CRH abolished the rise in plasma ACTH seen at 1700 hr in the NRS group but had little effect on earlier levels. The diurnal elevation in plasma corticosterone continued after anti-CRH treatment, but peak levels occurred earlier. Plasma ACTH and corticosterone were significantly correlated at the time of the diurnal surge, but not at 0800 hr or 1300 hr in the NRS controls or at any time point in the anti-CRH group. These results suggest that CRH is required for the diurnal surge of plasma ACTH. They also confirm previous observations by others that the adrenal cortex does not require active CRH or a diurnal surge of ACTH in order to exhibit a significant diurnal increase in secretion of corticosterone, and that factors other than CRH may be relatively more active than CRH in regulation of ACTH secretion during the time of circadian inactivity.     

Neuroendocrine effects of interferon alpha 2-a in healthy human subjects

The acute effects of interferon alpha-2a (3 x 10 IU im) on catecholamine and immunoreactive beta endorphin plasma levels, cortisol serum levels and lymphocyte beta 2-adrenoceptor density were evaluated in ten healthy volunteers. Interferon induced a significant increase in plasma norepinephrine; there was an increased norepinephrine standing response, too. On the contrary, epinephrine standing response was reduced by interferon. Lymphocyte beta 2-adrenoceptors decreased significantly after interferon administration; dissociation constant of binding was unchanged. Cortisol serum levels increased significantly with respect to control test, whereas immunoreactive beta endorphin did not change. These results support the hypothesis of functional relationships between neuroendocrine and immune systems; moreover they may be useful in clinical trials given the administration of interferon alpha in an increasing number of diseases.     

Alteration of circadian rhythmicity of CD3+CD4+ lymphocyte subpopulation in healthy aging

The CD4+ T helper/inducer and the CD8+ T suppressor/cytotoxic are major lymphocyte subsets that play a key role in cell-mediated immunity. Aging-related changes of immune function have been demonstrated. The purpose of this study is to analyze the dynamics of variation of these specific lymphocyte subsets in the elderly. In our study cortisol and melatonin serum levels were measured and lymphocyte subpopulation analyses were performed on blood samples collected every four hours for 24 hours from fifteen healthy young middle-aged subjects (age range 36-55 years) and fifteen healthy elderly male subjects (age range 67-79 years). A clear circadian rhythm was validated for the time-qualified changes of CD3+ and CD4+ cells with acrophase at night and for the time-qualified changes of CD8+ cells with acrophase at noon in young middle-aged subjects and for the time-qualified changes of CD3+ cells with acrophase at night and for the time-qualified changes of CD8+ cells with acrophase at noon in elderly subjects. No clear circadian rhythm was validated for the time-qualified changes of CD4+ cells in elderly subjects. No statistically significant correlation among lymphocyte subsets was found in elderly subjects. In elderly subjects CD3+ lymphocyte percentage was higher in the photoperiod and in the scotoperiod and cortisol serum level were higher in the scotoperiod in respect to young middle-aged subjects. In the elderly there is an alteration of circadian rhythmicity of T helper/inducer lymphocytes and this phenomenon might contribute to the aging-related changes of immune responses.     

Dissociation between increased growth hormone and prolactin secretion during the morning hours of early pregnancy in the rat

We investigated whether serum growth hormone (GH) concentration changes in association with the rise in serum prolactin (PRL) concentration known to occur during the early morning hours in the pregnant rat. Animals were kept in a room with the lights on from 0500 to 1900 hours (hr) daily and decapitated for the collection of trunk blood at 2200 or 2400 hr on Day 6 of pregnancy or at 0200, 0400, 0800 or 1000 hr on Day 6 of pregnancy. Serum GH concentration rose more than 4-fold from low levels at 2200 and 2400 hr to higher levels at 0400 and 0800 hr and then declined by 1000 hr. Serum prolactin (PRL) concentration followed a similar pattern except that it returned to low levels earlier, by 0800 hr. Serum luteinizing hormone, follicle-stimulating hormone and thyroid-stimulating hormone concentrations showed no significant changes. Serum GH levels at 0800 hr in pregnant rats were higher than those observed in cyclic rats (13 time periods sampled). The results demonstrate that serum GH concentration is elevated during a circumscribed period in the 6- to 7-day pregnant rat. The time of onset of the rise is similar to that for serum PRL but the elevation in GH levels persists longer than that for PRL.     

Neuro-endocrine correlations of hypothalamic-pituitary-thyroid axis in healthy humans

Neuro-endocrine hormone secretion is characterized by circadian rhythmicity. Melatonin, GRH and GH are secreted during the night, CRH and ACTH secretion peak in the morning, determining the circadian rhythm of cortisol secretion, TRH and TSH show circadian variations with higher levels at night. Thyroxine levels do not change with clear circadian rhythmicity. In this paper we have considered a possible influence of cortisol and melatonin on hypothalamic-pituitary-thyroid axis function in humans. Melatonin, cortisol, TRH, TSH and FT4 serum levels were determined in blood samples obtained every four hours for 24 hours from ten healthy males, aged 36-51 years. We correlated hormone serum levels at each sampling time and evaluated the presence of circadian rhythmicity of hormone secretion. In the activity phase (06:00 h-10:00 h-14:00 h) cortisol correlated negatively with FT4, TSH correlated positively with TRH, TRH correlated positively with FT4 and melatonin correlated positively with TSH. In the resting phase (18:00 h-22:00 h-02:00 h) TRH correlated positively with FT4, melatonin correlated negatively with FT4, TSH correlated negatively with FT4, cortisol correlated positively with FT4 and TSH correlated positively with TRH. A clear circadian rhythm was validated for the time-qualified changes of melatonin and TSH secretion (with acrophase during the night), for cortisol serum levels (with acrophase in the morning), but not for TRH and FT4 serum level changes. In conclusion, the hypothalamic-pituitary-thyroid axis function may be modulated by cortisol and melatonin serum levels and by their circadian rhythmicity of variation.     

Responses to epinephrine in patients with anorexia nervosa

To examine the sensitivity to epinephrine in patients with anorexia nervosa, 20-60 micrograms/kg body weight/min of epinephrine was infused for 30 min each in 5 patients and 5 controls. The increase in pulse rate and the decrease in diastolic blood pressure were significantly smaller in the patient group. Elevated plasma GH levels in the patients were markedly suppressed by epinephrine infusion. These results indicate the beta-adrenergic function is decreased at least in the cardiovascular system in patients with anorexia nervosa.     

Time dependent effects of hormones on rate of protein synthesis in lymphoid organs of chickens

Total protein content in blood serum and different lymphoid organs, such as bursa, spleen and thymus was investigated in chickens at two different circadian stages (0800 or 1600 hrs; early or late photophase) following administration of either saline or hormones (thyroxine or hydrocortisone or epinephrine). The results suggest that the lymphoid organs may respond differently to the exogenous administration of different hormones depending on the time of their administration.     

Leukocytosis of exercise: role of cardiac output and catecholamines

The effect of propranolol (5 mg iv) on the leukocytosis of exercise was studied in seven normal young males. Leukocyte counts, plasma norepinephrine (NE), epinephrine (E), and cardiac output were measured at rest and in the steady state of several submaximal work loads when subjects exercised on a cycle ergometer. The results in control experiments were compared with those obtained on a different day with propranolol. Propranolol decreased heart rate at all work loads (P less than 0.001) but had no effect on the increase in cardiac output at increasing work loads. Plasma NE and E levels were similar at rest and in exercise in control and propranolol studies. There was no effect of propranolol on the increase in leukocyte counts with increasing work loads. Although propranolol did not affect the increase in total leukocyte count, the increase in lymphocyte count at higher work loads was less with propranolol. We conclude that the demargination of leukocytes from the pulmonary circulation in exercise is probably a mechanical effect of the increase in cardiac output. However, we have not excluded a contribution from a humoral event that would decrease the adherence of leukocytes to endothelium during exercise. The smaller increase in lymphocytes at higher work loads in the presence of propranolol suggests that catecholamines affect the lymphocyte count over and above their effect on cardiac output.     

Epithelial distribution of neural receptors in the guinea pig small intestine

Neural and paracrine agents, such as dopamine, epinephrine, and histamine, affect intestinal epithelial function, but it is unclear if these agents act on receptors directly at the enterocyte level. The cellular localization and villus-crypt distribution of adrenergic, dopamine, and histamine receptors within the intestinal epithelium is obscure and needs to be identified. Single cell populations of villus or crypt epithelial cells were isolated from the jejunum of adult guinea pigs. Enterocytes were separated from intraepithelial lymphocytes by flow cytometry and specific binding was determined using fluorescent probes. Alpha1-adrenergic receptors were located on villus and crypt intraepithelial lymphocytes and enterocytes. Beta-adrenergic receptors were found on villus and crypt enterocytes. Dopamine receptors were found on all cell types examined, whereas histamine receptors were not detected (<10% for each cell population). These studies demonstrated that (1) receptors for epinephrine and dopamine exist on epithelial cells of the guinea pig jejunum, (2) beta-adrenergic receptors are found primarily on villus and crypt enterocytes and (3) intraepithelial lymphocytes contain alpha1-adrenergic, but have few beta-adrenergic, receptors. The presence of neural receptors suggests that these agents are acting, at least in part, at the enterocyte or intraepithelial lymphocyte levels to modulate intestinal and immune function.     

Effect of starvation and refeeding on the circadian rhythms of hematological and clinico-biochemical values, and water intake of rats

We investigated the effect of starvation for 24 hr and subsequent refeeding for 12 hr on the circadian rhythms of 39 hematological and clinico-biochemical parameters, and water intake of F344 rats. The rats scarcely drank any water during the starvation period, but subsequently their intake of water were normal, even in the light period. During starvation, 12 parameters such as serum levels of alkaline phosphatase activity and PaCO2 decreased with time-related and time-related increases of 8 parameters such as the erythrocyte count and cholinesterase activity. During refeeding for 12 hr, almost all these biochemical parameters were normalized, but none of the hematological values except the leukocyte count returned to normal levels. Starvation and refeeding had little affect on the circadian rhythms of others.     

Lymphocyte and granulocyte migration across the endothelial layer of bovine pulmonary artery intimal explants towards lymphocyte conditioned medium

An intravenous infusion of endotoxin into sheep results in accumulation of equal numbers of lymphocytes and granulocytes in the pulmonary microcirculation. The role of the sequestered lymphocytes in acute lung injury is not known. The present study examines whether lymphocyte migration through pulmonary endothelium contributes to endothelial damage and also examines the effect of lymphokines on granulocyte migration. Bovine pulmonary artery intimal explants were mounted in Boyden chambers and conditioned media, prepared from bovine peripheral blood lymphocytes, was used as the chemoattractant. The rate of 51Cr labelled bovine granulocyte lymphocyte migration into intimal explants was determined over a 3 hr incubation period. Permeability changes were assessed by adding trace amounts of 14C-sucrose and 3H-water to the upper well and following their rate of equilibration with the lower well. 6-Keto-PGF1 alpha was measured in the upper well. Lymphocyte conditioned media was found to be chemotactic for both lymphocytes and granulocytes (lymphocyte migration at 60 min: lymphocyte conditioned media = 18.5 +/- 2.3%, mean +/- s.e. RPMI control = 12.5 +/- 1.5; granulocyte migration at 120 min: conditioned media = 36.1 +/- 5.7, RPMI control = 18.2 +/- 3.0). Ultrastructural examination revealed leukocyte migration followed an orderly sequence during which the leukocytes maintained close contact with the adjacent endothelial cells. No structural evidence of endothelial cell damage was seen at any time examined. Granulocyte migration was associated with an increased rate of 14C-sucrose equilibration after 2 hr of incubation (lower well counts/upper well counts at 2 hr, RPMI control = 0.18 +/- 0.02; lymphocyte conditioned medium = 0.30 +/- 0.04) indicating alteration in the endothelial barrier function. Leukocyte migration, particularly lymphocyte migration, was accompanied by a marked increase in prostacyclin accumulation (3 hr: no leukocytes, 188 +/- 17 ng/ml; lymphocytes, 560 +/- 104). These in vitro findings suggest that lymphocytes and lymphokines may be involved in acute lung injury and also that permeability changes associated with granulocyte migration may depend on the chemoattractant.     

Seasonal hematology and serum chemistry of wild beluga whales (Delphinapterus leucas) in Bristol Bay, Alaska, USA

We collected blood from 18 beluga whales (Delphinapterus leucas), live-captured in Bristol Bay, Alaska, USA, in May and September 2008, to establish baseline hematologic and serum chemistry values and to determine whether there were significant differences in hematologic values by sex, season, size/age, or time during the capture period. Whole blood was collected within an average of 19 min (range=11-30 min) after the net was set for capture, and for eight animals, blood collection was repeated in a later season after between 80-100 min; all blood was processed within 12 hr. Mean hematocrit, chloride, creatinine, total protein, albumin, and alkaline phosphatase were significantly lower in May than they were in September, whereas mean corpuscular hemoglobin concentration, monocytes, phosphorous, magnesium, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltranspeptidase, and creatinine kinase were significantly higher. Mean total protein, white blood cell count, neutrophils, and lymphocytes were significantly higher early in the capture period than they were later. No significant differences in blood analyte values were noted between males and females. Using overall body length as a proxy for age, larger (older) belugas had lower white blood cell, lymphocyte, and eosinophil counts as well as lower sodium, potassium, and calcium levels but higher creatinine levels than smaller belugas. These data provide values for hematology and serum chemistry for comparisons with other wild belugas.     

Mechanisms of the haematological changes induced by hyperventilation

During voluntary hyperventilation an increase in the lymphocyte and thrombocyte counts occurs, paralleled by an increase in plasma epinephrine and norepinephrine. All these changes are rapidly reversible after hyperventilation and are followed by an increase in the neutrophil granulocyte count. The pathophysiological mechanisms of these changes were investigated by comparison of the hyperventilation-induced changes of the blood picture in 11 normal, 9 splenectomized and 12 beta-blocked volunteers. Splenectomy did not affect the hyperventilation-induced mobilization of lymphocytes and neutrophils but totally suppressed the change in the thrombocyte count. beta-blockade by 80 mg propranolol did not suppress the hyperventilation-induced increase in neutrophils. It reduced the absolute increase of lymphocytes and thrombocytes by half, but it also increased the baseline counts of these cells. The study shows that hyperventilation mobilizes thrombocytes from the spleen but not from extralienal pools, and that lymphocytes and neutrophils are mobilized from extralienal pools. Whereas neutrophil mobilization is not suppressed by beta-blockade, the reduction of hyperventilation-induced mobilization of lymphocytes and thrombocytes may be due to a reduction in the size of the mobilizable cell pools, and therefore cannot be interpreted as a sure indication that adrenergic mechanisms are involved in their hyperventilation-induced mobilization.     

Cardiorespiratory and cellular changes with interleukin 2 infusion in sheep

Recombinant interleukin 2 (rIL-2) administration, a new form of therapy for patients with far-advanced cancer, is associated with a "third space" syndrome, i.e., pulmonary edema, respiratory distress, and hypoxemia, which limits the dose and duration of treatment. To extend our knowledge regarding this toxicity, we established a sheep chronic lung lymph fistula model and measured hemodynamics, arterial blood gases, caudal mediastinal (lung) lymph flow (QL), and blood and lung lymph cellular changes before, during, and after (recovery) a 3-day continuous rIL-2 infusion (9 x 10(5) U/kg). Moderate systemic hypotension, mild pulmonary hypertension, and an increase in alveolar-arterial PO2 gradient was present on day 3 of rIL-2 infusion. QL increased from a base line of 1.9 +/- 0.2 to a maximum of 4.3 +/- 1.1 ml/15 min on day 3 of rIL-2 infusion. At no time was there a change in lymph-to-plasma protein ratio. The leukocyte count increased significantly to 16.1 +/- 4.5 x 10(3) cells/mm3 at recovery day 1. The percentage of blood lymphocytes decreased significantly by day 1 of rIL-2 infusion, returned to base-line levels on day 3, and significantly increased on day 2 of recovery. Lung lymph lymphocytes decreased significantly on days 1 and 2 of rIL-2 infusion. There was a shift in their size; i.e., their area increased from 32 +/- 7 to 57 +/- 19 micron 2 (P less than 0.05) by day 2 of rIL-2 infusion. By day 1 of recovery, lung lymph lymphocyte counts increased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epinephrine-induced conditioned taste aversion

The ability of the hormone epinephrine to induce a conditioned taste aversion was investigated in three experiments. Aversions induced by epinephrine appear more easily conditioned to a highly preferred sucrose solution than to a less preferred sucrose/saline solution. A dose-response curve also exists; better conditioning is evident following injection of either 0.3 or 0.5 mg/kg epinephrine than it is following a 0.1 mg/kg dose. A arcadian rhythmicity also occurs for epinephrine-induced sucrose aversions. When the endogenous levels of this hormone are at trough, conditioning is greater than when they are elevated. This circadian pattern is interpreted with respect to the degree of discriminability between endogenous and exogenous epinephrine levels.