PubMed Health⌕ Search

Biomedical subjects

S Porta

Publications and source records attributed to S Porta.

70 records · Page 4Linked to original sources
PubMed1982

Changes in blood catecholamines, insulin, corticosterone and glucose during the course of the Sephadex inflammation.

During an acute inflammation, the blood levels of noradrenaline, dopamine and insulin increase uniformly until the fourth day, then reach a climax which for dopamine is above the norm, while the suppressed levels of noradrenaline and insulin approach the norm. All values decrease on the fifth day (end of the experiment). Glucose behaves inversely, showing a minimum on the fourth day. Corticosterone displays two peaks, on the first and fourth days. The adrenaline level differs distinctly from these patterns: it is elevated on the second, fourth and fifth days. By releasing each catecholamine independently, the organism can possibly influence the course of the inflammation.

Animals↗
PubMed1982

[Implantable repository adrenaline tablets for long-term studies on rats].

Implantable coated Eudragit matrix tablets containing adrenaline in various concentrations should overcome the problem of additional handling stress during long term infusions. The efficiency of those tablets was tested in vitro, as well as in vivo using labeled adrenaline. Both in vitro and in vivo testing yielded satisfactorily output rates up to 20 h whereby the liver and serum content of 14C-fragments served as an additional prove for the postulated mode of action. Good correlation has been found between the mentioned out-put rates and adrenaline serum levels (measured according to Da Prada).

Animals↗
PubMed1981

[The metabolism of hydrocortisone, prednisolone and fluocortolone (author's transl)].

The plasma levels of hydrocortisone, prednisolone and fluocortolone were studied in healthy males by a competitive protein-binding technique after separation by thin-layer chromatography. Cortisone showed a mean morning level of 440 nmol/l +/- 165 nmol/l and a half life of 4.8 hours. The half life of prednisolone was determined after intravenous injection of 25 mg and found to be 2.4 hours and that of fluocortolone, after oral administration of 60 mg, was calculated to be 1.7 hours.

Adolescent↗
PubMed1981

Adrenal depletion during hypoglycemia without participation of the Golgi apparatus.

Adrenal depletion in rats due to hypoglycemia was effected by prolonged administration of adrenaline, without artificial increase in insulin levels. In spite of significantly enhanced catecholamine turnover in this stadium Golgi complexes - which are usually reported to develop hypertrophy during adrenal depletion using insulin induced hypoglycaemia - could never be observed. This leads to the conclusions, that firstly the presence of hypertrophic Golgi complexes is not necessarily linked with increased catecholamine turnover and secondly that permanent adrenalin application suppresses and insulin application promotes the formation of Golgi systems. Moreover, our electromicrographs do strongly suggest, that catecholamine turnover is linked with the rough endoplasmatic reticulum.

Adrenal Medulla↗
PubMed1980

Effects of adrenaline-tablets on rat heart cells in tissue culture at normal and raised temperature.

Primary cultures of rat heart cells were incubated at 37 degrees C or 39.5 degrees C. For permanent treatment with adrenaline recently developed tablets were added to the cultures. After 10 hours the cell counts, glucose, lactate, LDH, alpha-HBDH and GOT were determined. Permanent adrenaline-application led to a decrease of cell counts, an increase of lactate, LDH, alpha-HBDH and GOT. The results indicate an injured membrane function of rat heart cells. Raised temperature sensitized the cells for adrenaline-treatment.

Animals↗
PubMed1979

The influence of a permanent isoproterenol (ISO) application on the dynamics of the Sephadex inflammation.

The influence of Isoproterenol on the number of the different types of white blood cells appearing during the course of the Sephadex inflammation was investigated in rats. Isoproterenol treatment causes a decrease of the number of the immigrating neutrophils within the first two days and an increase of the lymphocytes during almost the entire experiment. A sudden decrease of the number of these cell types, indicating a massive cell destruction, was followed by immigration of eosinophilic granulocytes after 24 hrs. Isoproterenol accelerated and augmented this immigration. We conclude, that perishing neutrophils and lymphocytes produce or mediate the production of factors which attract eosinophils and moreover that Isoproterenol enhances the production or the effect of these factors. The mechanism underlying this enhancement is not known. We suppose a specific beta-adrenergic influence, because we could not reproduce this increasing effect with adrenaline.

Animals↗
PubMed1979

Inhibition of adrenalin depletion in hypoglycaemic rats following permanent adrenalin application by depot capsule.

Chronic treatment of rats with adrenalin by means of a subcutaneous depot capsule (cont. 40 mg dry adrenalin/HCl, Merck, ca. 10 mg ascorbic acid and ca. 0.4 ml 0.9% NaCl, and sealed with a dialysis membrane to provide constant adrenalin output) leads after a primary hyperglycaemic phase to hypoglycaemia. At the onset of hypoglycaemia the adrenalin contents of the suprarenal glands decrease to levels of about one third of their normal state. Simultaneous glucose infusions by intraperitoneal depot capsules prevent hypoglycaemia as well as adrenalin depletion. The fact that adrenalin depletion does not always correspond with blood sugar levels below 80 mg/dl and that this depletion could be prevented by glucose infusions altogether seems to provide a strong hint that the mentioned depletion is due to hypersecretion and not to the blocking of adrenalin synthesis. If is true, then there must be no direct negative feed-back system between adrenalin secretion and its extraglandular level.

Adrenal Medulla↗
PubMed1979

Antiinflammatory substances appearing during an acute inflammation and the alteration of their properties by isoproterenol (ISO). An in vivo investigation in rats.

It could be demonstrated that antiinflammatory substances appear during the course of an acute inflammation. The inhibition of leucocyte immigration into the site of inflammation (caused by Sephadex) was taken as criterion for the antiinflammatory property. The highest quantity or effect of the antiinflammatory substances was found on the 3rd day after inflammation has started. Not only the absolute number of cells but also the composition of the cellular exudate (compared with a fresh inflammation) was changed: The percentage rate of the neutrophils was reduced, whereas the portion of the eosinophils and the lymphocytes was increased. A permanent ISO application on the animals altered the quantity of the composition of these substances, in consequence of which the immigration of eosinophils and lymphocytes was promoted. The reaction of the neutrophils was unaffected.

Animals↗
PubMed1979

Evidence for adrenalin secretion regardless of high extraglandular levels.

Chronic adrenalin administration (4 mg/18 hrs) by means of a subcutaneous depot capsule leads to hypoglycaemia and adrenalin depletion of the suprarenal gland within 18 hrs. Stimultaneous application of glucose prevents hypoglycemia as well as adrenalin depletion. By injection of 3H-labelled tyrosine 10, 20 or 30 min before killing and subsequent detection of the quantity of labelled tyrosine and adrenalin in the sera by mixing them with a standard solution containing considerable amounts of unlabelled tyrosine and adrenalin, and by passing them through a Sephadex G-10 column and finally detecting the radioactivity of the fractions in a liquid scintillation-counter, we could prove that during the stage of hypoglycaemia an enhanced adrenalin synthesis and secretion did take place regardless of a high extraglandular level. In animals treated with adrenalin and glucose, NaCl solution or alpha-methyl-tyrosine methylester-HCl no increased resp. no turnover at all could be seen. Therefore, we conclude that there is not only a lack of a direct negative feedback system between adrenalin synthesis, secretion and extraglandular level but also that the enhanced synthesis of adrenalin that can take place in spite of a high serum level can initiate a fatel circulus vitiosus.

Adrenal Glands↗
PubMed1977

[Serological and histological investigations as well as studies on changed food uptake during adrenaline application by intraperitoneal depot capsule].

The authors have developed a method for long-term permanent application of water soluble substances by a intraperitoneal depot capsule [KLINGENBERG et al., Exp. Path. 13, 302-311 (1977)]. The present study deals with the effects on the liver and several metabolic processes induced by continuous long-term adrenaline application by means of such a depot capsule.

Animals↗
PubMedDate not supplied

Prolonged hyperadrenalinemia impairs exercise ability in rats.

This study was performed on rats with sustained (24 h) hyperadrenalinemia produced by sc implantation of retard adrenaline (A) tablets. Comparing with control, sham-operated animals, in A-treated rats duration of endurance exercise until exhaustion was shortened by approx. 40%. This was accompanied by: significant decreases of the pre-exercise muscle glycogen and creatine phosphate values in both "slow twitching" (soleus) and "fast twitching" (white portion of gastrocnemius) muscles, and of ATP content in soleus. Muscle lactate and pyruvate contents as well as blood glucose and FFA levels were elevated. After exercise muscle substrate and metabolite contents were similar in both groups in spite of the difference in exercise duration. It is concluded that prolonged hyperadrenalinemia diminishes the intramuscular energy substrate content, thereby reducing endurance capacity of rats.

Animals↗