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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present work outlines the presence of specific binding for chinook salmon growth hormone (sGH) in different tissue preparations of rainbow trout. Optimal incubation conditions (pH, Tris, MgCl2) were determined. Specific binding was very sensitive to salt concentration during incubation. The specific binding reached a plateau after 15 and 25 hr of incubation at 12 and 4 degrees. At 20 degrees, specific and nonspecific binding were not stable. Specific binding dissociation was slower than association and was only partial. The binding was saturable (Bmax = 187 +/- 167 pmol), of high affinity (Ka = 2.4 +/- 0.8 10(9) M-1), and very specific for GH, properties which are in agreement with the characteristics of hormonal receptors. Sea bream and mammalian GH appeared 2- and 30-fold, respectively, less potent than cold sGH2 for displacing 125I-sGH2. Tissue preparations from ovary, testis, fat, skin, cartilage, gill, blood pellet, brain, spleen, kidney, and muscle showed significant saturable binding.
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PMID:Presence of specific growth hormone binding sites in rainbow trout (Oncorhynchus mykiss) tissues: characterization of the hepatic receptor. 202 19

Thermoregulation was investigated pre and postoperatively in 5 and only preoperatively in 7 patients with suprasellar pituitary adenomas by exposing them to external cold and heat in a climatic chamber. Five healthy subjects served as controls. Body core and skin temperatures, oxygen consumption, electromyographic activity, skin blood flow and local sweating rates were continuously measured. Threshold temperatures for activation of heat production and heat loss were calculated from these data. Hormone analysis was performed before and after stimulation with releasing factors. In the patients, core temperatures as well as threshold temperatures for heat production and heat loss were elevated by about 0.5 degrees C as compared with controls. This elevation of core and threshold temperatures was achieved, despite a reduced resting metabolic rate, by a reduction of skin blood flow indicated by a low mean skin temperature. After successful operation the thermoregulatory alterations normalized. Serum levels of growth hormone were reduced preoperatively and stimulation by GHRF did not cause an appropriate increase. Prolactin was elevated in 6 patients with prolactinomas, but there was no correlation with changes in thermoregulatory threshold temperatures. Stimulation of the other hypophyseal hormones by the combined anterior pituitary function test revealed a normal hormonal response. Apart from prolactin there were no significant hormonal changes postoperatively. It is concluded that disturbances of temperature regulation are present in patients with suprasellar adenomas, but that they are not detectable by routine clinical methods. These alterations probably depend on a disturbance of hypothalamic function and are reversible by surgery.
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PMID:Modifications of thermoregulation in patients with suprasellar pituitary adenomas. 204 43

The effects of central 5-hydroxytryptamine (5-HT) infusions on the cold-stimulated thyrotropin (TSH) levels were studied in male rats. Stainless-steel cannulas were implanted stereotaxically into the anterior or the posterior third ventricle or just lateral to the hypothalamic paraventricular nuclei bilaterally 7 days before experiments. Infusion of 5-HT (4.5 and 9 micrograms/rat) into the posterior third ventricle attenuated significantly the cold-stimulated TSH levels. Inversely, infusion of 5-HT (9 micrograms/rat) into the anterior third ventricle augmented significantly the TSH cold response. Bilateral 5-HT infusions into the vicinity of the hypothalamic paraventricular nuclei did not affect the TSH cold response. Serum prolactin levels increased significantly after 5-HT administration into the anterior and the posterior third ventricle, but no consistent effect on growth hormone (GH) levels could be detected. Infusion of 5-HT into the anterior and the posterior third ventricle decreased body temperature irrespective of the observed hormonal response to 5-HT. The results are in favor of a dual and possibly site-dependent role for 5-HT in the regulation of the cold-stimulated TSH secretion in the rat. The opposite effects of 5-HT on the TSH cold response may result from the predominant inhibition of either the thyrotropin-releasing hormone or the somatostatin-secreting cell groups.
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PMID:Site-dependent action of intracerebroventricular 5-hydroxytryptamine on the cold-stimulated thyrotropin secretion in male rats. 210 86

The ability of hormones to bind to their functional receptors on turtle (Pseudemys scripta) endocrine target tissues in the cold was tested by treating tissues with secretagogues at low temperatures (5-15 degrees) and then following subsequent target stimulation in the absence of secretagogue at a warm temperature (28 degrees). Administration of thyrotropin-releasing hormone (TRH), corticotropin-releasing hormone, and growth hormone-releasing hormone to pituitaries at low temperatures (20 degrees or below) suppressed responses in growth hormone (GH) and thyrotropin (TSH) secretion and there was little or no response in pituitaries subsequent to warming. In contrast, gonadotropin-releasing hormone treatment of pituitaries, TSH treatment of thyroid glands, and gonadotropin (FSH and LH) treatment of testes in the cold (down to 5 degrees) was followed by a large response in the target glands (secretion of LH, thyroxine, and testosterone (T), respectively) following warming. Additional studies with FSH and LH showed that these hormones can bind to testes rapidly (within 5 min) at low temperatures where no acute response is observed, although the dose sensitivity and the extent of this priming in the cold are less than at warm temperatures. Thus, postreceptor events may be more important than binding per se for temperature effects on hormone responses of tissues, but even this component of cell function varies among tissues. The effects of a receptor-independent secretagogue (tetraethylammonium chloride), which causes cell depolarization by blocking K+ efflux, were also blocked at low temperatures in thyrotropes and somatotropes but not in gonadotropes. Rapid depressions in TSH and GH secretions following cooling of TRH-stimulated pituitaries and of T secretion in LH-stimulated testes provide further evidence for cold sensitivity of postreceptor processes in these tissues.
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PMID:The role of hormone binding in the cold suppression of hormone stimulation of the pituitary, thyroid, and testis of the turtle. 228 80

Maximal growth hormone (GH) increments following exercise were compared in asthmatic (n = 14) and normal (n = 8) children. Exercise, which consisted of 6 min ergometer cycling while breathing cold dry (CD) air, induced asthma in all asthmatic patients but not in normal subjects. Baseline plasma GH levels were similar in both groups. Following exercise, however, asthmatic patients had significantly higher mean GH increments than normal subjects (14.8 vs 4.9 ng/ml, P less than 0.025). To evaluate the possible role of bronchoconstriction in the GH response all subjects exercised again, this time while breathing warm humid (WH) air. Despite the absence of exercise-induced asthma (EIA) while breathing WH air, asthmatic patients still had significantly higher mean GH increments than normal subjects (9.2 vs 2.3 ng/ml, P less than 0.05). We conclude that some asthmatic children show excessive GH secretion after exercise regardless of inspired air conditions or the development of EIA.
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PMID:Growth hormone response to exercise in asthmatic and normal children. 233 18

To establish whether thyroid hormone modifies the heart rate directly or through an action on other neuroendocrine modulators, the authors have examined several animals models differing in the plasma levels of such compounds. Induction of the hypothyroid state in rats produced a slow onset of bradycardia, which may be removed by a prolonged triiodothyronine treatment. The involvement of TSH was excluded as, by comparing thyroidectomized, hypophysectomized and cold exposed rats, the heart rate was found to vary according to the thyroid levels and not to the TSH levels. Moreover growth hormone, corticotropin and gonadotropins do not influence the heart rate, as the bradycardia induced by hypophysectomy was fully removed by triiodothyronine treatment. The lack of influence by ACTH and GnH was confirmed by treatment of thyroidectomized rats with corticosteroids or testosterone, respectively. Finally, thyroid hormone did not act on the heart rate by changing the norepinephrine output at the sympathetic nerve endings in the heart. In fact, thyroidectomy produced a more intense bradycardia than sympathectomy, and such bradycardia was equally removed by triiodothyronine treatment in thyroidectomized rats and in thyroidectomized and then sympathectomized ones. The authors suggest that the direct effect of the thyroid hormone on cardiac chronotropism is due to an early enhancement of beta-adrenoceptors, followed by a late modification of the electrophysiological properties of the myocardium.
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PMID:The direct effect of the thyroid hormone on cardiac chronotropism. 248 2

Previous research has established that growth hormone pulse amplitude declines with increasing age. The purpose of this study was to determine whether this decline is associated with (1) increased pituitary response to somatostatin, and/or (2) increased number or affinity of pituitary somatostatin receptors. In the first study, pituitary slices from young (3-4 months), middle-aged (12-14 months), and old (22-24 months) male Fischer 344 rats were superfused with minimal essential medium (1 ml/min) and fractions collected at 5-min intervals. Tissues were stimulated with 10(-7) M hpGRF (1-44) for 1 min and, 40 min later, with hpGRF in the presence of 5 x 10(-9) M somatostatin-14 or somatostatin-28. Two pituitaries from each age group were superfused simultaneously and the experiment replicated 4 times. Growth hormone release was measured by radioimmunoassay. In a second study, somatostatin receptors in purified pituitary membranes from the three age groups were compared using iodo-[Tyr0]-D-Trp8 somatostatin-14. Animals from each age group were pooled, membranes extracted, and incubated with increasing doses of cold peptide. Binding characteristics were analyzed by Scatchard analysis and Ka and Bmax calculated. Results indicated that (1) basal growth hormone release diminished both with age and somatostatin administration, (2) GRF-induced release of growth hormone was similar in all age groups when data were expressed as percent increase from baseline, and (3) in the presence of somatostatin-14, GRF-induced release of growth hormone was attenuated in old as compared to young or middle-aged rats (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increased pituitary response to somatostatin in aging male rats: relationship to somatostatin receptor number and affinity. 257 35

A 28 year-old woman was admitted to Jichi Medical School Hospital because of amenorrhea, cold intolerance, easy fatigability and body weight loss. She was pregnant at the age of 26 years. She delivered a 3230 g healthy girl at full term without any complications. However, she did not have any lactation or recurrence of menstruation after the delivery. Serum cortisol was 0.7 micrograms/dl, and plasma adrenocorticotropic hormone (ACTH) was less than 10 pg/ml. Both hormones failed to increase in response to insulin-induced hypoglycemia or exogenous arginine vasopressin. However, serum cortisol and urinary excretion of 17-hydroxycorticosteroids (17-OHCS) were significantly increased by the repeated administration of ACTH. Serum prolactin was 2.2 ng/ml and the level did not rise after the administration of thyrotropin releasing hormone (TRH). Responses of release of adenohypophysial hormones including gonadotropins, growth hormone and thyroid stimulating hormone (TSH) were normal. Serological studies showed an antibody to the pituitary gland which was demonstrated by an indirect immunofluorescence technique. Plain skull X-ray film and brain computerized tomography revealed an empty sella of the normal size. These results indicate the presence of partial deficiency of ACTH and prolactin, and that autoimmune disorders may be involved in the pathogenesis of her hypopituitarism.
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PMID:A case of partial hypopituitarism with empty sella following normal course of pregnancy and delivery. 301

The specific binding of 125I-labelled human chorionic gonadotrophin (hCG), human low-density lipoprotein (hLDL), human FSH (hFSH) and human prolactin (hPRL) to homogenates of human corpus luteum tissue was measured. Specific binding of 125I-labelled hCG was dependent on the temperature and duration of incubation, was inhibited by divalent metal ions or chelating agents, and increased linearly with homogenate concentration. Recovery of bound hormone was more effective using Millipore filtration or polyethylene glycol precipitation compared with centrifugation alone. Binding of 125I-labelled hCG was inhibited specifically by low levels of hCG and human LH (hLH) but not by ovine LH or bovine LH. Incubation of human luteal tissue with ice-cold citrate buffer (pH 3) released more than 90% of specifically bound 125I-labelled hCG within 5 min. This treatment inactivated LH receptors, but did not affect the immunoactivity of hLH released, enabling the measurement of released hormone by radioimmunoassay. Scatchard plots of binding of 125I-labelled LDL to human corpus luteum demonstrated a single class of binding sites. Binding was saturable, increased linearly with increasing concentration of homogenate, and was displaceable by low concentrations of unlabelled LDL. Binding of 125I-labelled hPRL to human luteal homogenates was increased by Mg2+ and was specific for lactogenic hormones (human prolactin, human growth hormone and ovine prolactin). Binding of 125I-labelled hFSH was not dependent on divalent metal ion concentration (in marked contrast to hFSH binding to immature pig granulosa cell receptors) and was displaced by hFSH preparations but not by hPRL, ovine LH or hCG at 1 microgram/ml. These results establish optimal conditions and hormone specificities for the measurement of human luteal gonadotrophin and LDL receptors, and methods for the estimation of hLH/hCG endogenously bound to human corpus luteum tissue.
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PMID:Specific binding sites for LH/chorionic gonadotrophin, low-density lipoprotein, prolactin and FSH in homogenates of human corpus luteum. I: Validation of methods. 310 40

A technique is described to study the effect of acetylation of individual lysine residues in peptide hormones on the affinity for their receptors, and is illustrated for the case of human growth hormone (hGH) binding to somatogenic receptors. The hGH was partially acetylated with high specific activity [3H]-acetic anhydride and the product ([3H]-Ac-hGH) was incubated with solubilised affinity-purified somatogenic receptors (from male rat liver) in the presence and absence of excess unlabelled hGH. The receptor-bound and unbound labelled hormone were separated by gel filtration and subjected to HPLC tryptic peptide mapping after the addition of cold carrier Ac-hGH. Peaks of [3H] radioactivity were assigned to peptides corresponding to the acetylation of specific lysine residues in the hGH sequence by amino acid analysis and sequencing. Comparison of the relative intensities of corresponding [3H] peaks in the peptide maps of added receptor, bound and unbound [3H]-Ac-hGH, enabled the relative receptor-binding potencies of different acetylated hGH species to be determined. Acetylation of lysine 168 or 172 in hGH greatly decreases its receptor-binding affinity, acetylation of lysine 115 probably causes a minor decrease, whereas acetylation of lysines 38, 70, and the N-terminal amino group have no appreciable effect. Acetylation of lysine 140 causes a significant increase in receptor-binding affinity.
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PMID:Determination of the effect of acetylation of specific lysine residues in human growth hormone on its affinity for somatogenic receptors by an affinity selection technique. 312 56


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