Glutamate decarboxylase and γ-Aminobutyrate transaminase in developing rat brain

Résumé Le décarboxylase de glutamate (GAD) et le transaminase -aminobutyro--cétoglutarique (GABAT) ont été étudiés dans le cerveau du rat pendant le développement postnatal. Le résultat le plus frappant de cette recherche a été de montrer que le rapport de ces deux enzymes est à peu près constant au cours du développement. Ce rapport (GABAT/GAD) est de 2,5 à 3,7.     

Increase in rabbit hypothalamic histidine decarboxylase activity after oophorectomy and thyroidectomy

Zusammenfassung Die Histidin-Decarboxylase-(HD)-Aktivität im Hypothalamus des Kaninchens wurde nach Oophorectomie und Thyroidectomie gemessen. Die Resultate zeigten, dass die HD-Aktivität sich 20 Tage nach der Oophorectomie und der Thyroidectomie verdoppelt. 20 Tage nach kombinierter Oophorectomie und Thyroidectomie stieg die HD-Aktivität ungefär 4mal, verglichen mit der Aktivität des Kontrollmatrials. Sham-operierte Kontrollen zeigten keine Veränderungen der HD-Aktivität im Hypothalamus.     

The effect of continuously cooling the hypothalamic preoptic area on antibody titre in the rat

Summary Continuous cooling of the hypothalamic preoptic area for 5 days, as well as sublethal infection withSalmonella enteritidis, increased the titre of antibodies against sheep erythrocytes, suggesting that the febrile response stimulates the humoral immune response.We thank Dr W. Mannheim from the Institute of Hygiene for kindly supplying the cultures ofS. enteritidis. This work was supported by the Schwerpunktprogramm Temperaturregulation und-adaptation of the Deutsche Forschungsgemeinschaft.     

Glutamate decarboxylase activity in brain regions of differentially-housed mice; a difference in the olfactory bulb

Summary Glutamate decarboxylase (GAD) activities were determined in homogenates of 8 brain regions of mice that had been differentially housed (isolated vs grouped) for 4–9 weeks. GAD activity was lower in whole forebrains and in olfactory bulbs of isolated mice, changes which might be associated with their increased aggressiveness.     

Histidine decarboxylase and DOPA decarboxylase in the stomach of the developing rat

Zusammenfassung Im Magen der fötalen Ratte erreicht die Dopadecarboxylase-Aktivität 19 Tage nach der Paarung Werte, die den Aktivitätswerten des erwachsenen Tieres entsprechen. Die Aktivität bleibt auch während der weiteren Entwicklung hoch. Die Histidindecarboxylase des fötalen Rattenmagens ist während der embryonalen Entwicklung hoch, aber die Aktivitätswerte fallen bei der Geburt zu nicht messbaren Werten ab. Ungefähr 8 Tage post partum steigt die Histidindecarboxylase des Magens wieder an und erreicht einen Monat nach der Geburt Werte, die den Aktivitätswerten des erwachsenen Tieres entsprechen. In der jungen Ratte wird die Magenhistidindecarboxylase weder durch Gastrininjektion noch durch Hungern beeinträchtigt. Vom 18. Tag nach der Geburt an kann die Enzymaktivität durch Hungern verringert und durch Gastrin wieder erhöht werden.     

Glutamate and GABA levels and glutamate decarboxylase activity in brain regions of rats after prolonged treatment with alkali cations

Resume L'administration chronique des cations des métaux alcalins (Na⁺, Rb⁺, Cs⁺) à les rats a provoqué la croissance des niveaux de glutamate et GABA dans certaines régions du cerveau. On n'a remarqué aucun changement en activité GAD de ces régions.     

Influence of castration and testosterone replacement on hypothalamic tyrosine hydroxylase activity in the rat

Summary Hypothalamic tyrosine hydroxylase (TH) activity of castrate rats is modulated by testosterone propionate (TP) in vivo. Kinetic studies revealed that bothV _max andK _m were virtually unaltered for substrate tyrosine in the presence of an excess of DMPH₄ cofactor. TP replacement to castrate rats increased theK _m for added DMPH₄ cofactor, whileV _max decreased. These results suggest that TP decreases TH activity of castrate rats by inhibiting the enzymereduced pteridine cofactor complex.     

Influence of castration and testosterone replacement on hypothalamic tyrosine hydroxylase activity in the rat.

Hypothalamic tyrosine hydroxylase (TH) activity of castrate rats is modulated by testosterone propionate (TP) in vivo. Kinetic studies revealed that both Vmax and Km were virtually unaltered for substrate tyrosine in the presence of an excess of DMPH4 cofactor. TP replacement to castrate rats increased the Km for added DMPH4 cofactor, while Vmax decreased. These results suggest that TP decreases TH activity of castrate rats by inhibiting the enzyme-reduced pteridine cofactor complex.     

Is the basal activity of rat stomach histidine decarboxylase affected by antrectomy?

The serum gastrin concentration and the gastric histidine decarboxylase activity are high in freely fed, unoperated rats but low in antrectomized rats. Following food deprivation the serum gastrin level and the enzyme activity are reduced simultaneously in the unoperated rats. After fasting for 36-48 h - but not before - the enzyme activity drops to the same low levels as in antrectomized rats.     

Glutamate decarboxylase in barley aleurone and its relationship toα-amylase development during germination

Résumé L'enzyme glutamate décarboxylase se trouve dans les extraits d'eau de l'aleurone de l'orge. Au début de la germination, l'activité de cette enzyme augmente, mais après, quand apparait l'enzyme -amylase, elle diminue. Quoiqu'au dessous d'une concentration de 2×10^–6 M l'acide -amino butyrique (GABA) n'affecte pas l'activité de l'-amylase in vitro, la GABA à 5×10^–6 M peut provoquer une inhibition de 25% qui n'est pas modifiée par des concentrations de GABA comprises entre 5×10^–6 M et 10^–3 M.     

Histidine decarboxylase in the bone marrow of the rat

Résumé Dans l'étude ci-dessus la formation d'histamine dans la moelle osseuse du rat adulte a été attribuée à une enzyme identique ou semblable à la décarboxylase d'histidine du rat foetal. Par conséquence, l'enzyme de la moelle osseuse diffère de l'enzyme qui, étant présente dans l'écorce rénale des animaux adultes, forme l'histamine.     

Gonadotrophic activity in hypothalamic extracts

Résumé Si l'on administre à des rats stériles par testostérone des extraits hypothalamiques de mouton préparés suivant la technique deGuillemin, on déclenche l'apparition des corps jaunes aussi bien chez les rats entiers que chez les animaux privés d'hypophyse. Ces extraits ont une activité gonadotrophique intrinsèque.     

Neuron numbers in hypothalamic nuclei of young, middle-aged and aged male rats

Morphologic analysis of nine hypothalamic areas revealed significant decreases in the number of neurons per unit area in the ventral medial and arcuate nuclei. These data suggest that altered neuron numbers in the VMW and perhaps the ARC may participate in the well documented reductions in endocrine and neuroendocrine function observed in aging rats.     

Neuron numbers in hypothalamic nuclei in young,middle-aged and aged male rats

Summary Morphologic analysis of nine hypothalamic areas revealed significant decreases in the number of neurons per unit area in the ventral medial and arcuate nuclei. These data suggest that altered neuron numbers in the VMW and perhaps the ARC may participate in the well documented reductions in endocrine and neuroendocrine function observed in aging rats.     

Effect of deglycyrrhizinized liquorice on gastric acid secretion,histidine decarboxylase activity and serum gastrin level in the rat

Zusammenfassung Nachweis, dass die Behandlung mit einem deglycyrrhizinierten Lakrizpräparat die basale Säurereaktion bei Ratten hemmt. Erhöhtes antrales pH führt zu vermehrter Freisetzung von antralem Gastrin mit bedeutender Aktivierung der Histidindecarboxylase in der Magenschleimhaut.

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Acknowledgments: This study was supported by the Swedish Medical Research Council No. B73-04x-1007-08 and by the Albert Påhlsson Foundation.     

Increase in the hypothalamic tyrosine hydroxylase activity after lesion of the catecholaminergic neurons of the rat pontine tegmentum]

Hypothalamic tyrosine hydroxylase activity is increased 6 and 18 h after bilateral lesioning of the Locus Coerulues, in the Rat. An adrenocortical hypertrophy was observed previously, under the same experimental conditions. The neurochemical and neuroendocrinological implications of theses results are discussed.     

Changes in cAMP concentration in the rat preoptic area during synchronized and desynchronized sleep

Summary cAMP concentration was found to be significantly lower during desynchronized sleep than during synchronized sleep in the preoptic area of rats kept at normal laboratory temperature. No significant changes in cerebral cortex cAMP concentraion were observed in the same experimental conditions.This work was supported by grants from Consiglio Nazionale delle Ricerche and Ministero della Pubblica Istruzione.The authors wish to thank G. Mancinelli and L. Sabattini for technical assistance and M. Luppi for secretarial assistance.     

Glutamate dehydrogenase activity in normal and tumoural skin in humans

Résumé Les auteurs ont étudié l'activité de la glutamate déhydrogénase dans la peau normale et dans les épithéliomes de la peau chez l'homme. Ils ont observé que l'enzyme est dans les tumeurs beaucoup plus active que dans la peau normale. De même, dans l'épithéliome, l'inhibition par le Zn⁺⁺ et la O-phénantroline necessite de plus hautes concentrations que pour la peau normale. Les modifications constatées pourraient servir au diagnostic différentiel des tumeurs de la peau chez l'homme.     

Changes in cAMP concentration in the rat preoptic area during synchronized and desynchronized sleep

cAMP concentration was found to be significantly lower during desynchronized sleep than during synchronized sleep in the preoptic area of rats kept at normal laboratory temperature. No significant changes in cerebral cortex cAMP concentration were observed in the same experimental conditions.