The cytoarchitecture of the adrenal medulla in the rat.

The disposition of adrenaline and noradrenaline storing cells in the adrenal medulla has been studied in the rat. It has been demonstrated that no morphological or functional reason exists for the follicular designation of clumps of chromaffin cells in the medulla. No significant difference was found between the outer and inner zone as regards the frequency of NA cells by morphometric and statistical methods. The cytoarchitectural differences between adrenaline- and noradrenaline-storing cell arrangement are described. Special features of the interrelation between noradrenaline storing cells, cortical cells and the connective tissue framework are stressed. The light and electron microscopic appearance of two types of cortical cells, assumed to represent different states of functional activity is described.     

The response of rat adrenal medulla to oxytocin

Effects of oxytocin (OT) on the adrenal chromaffin tissue of male rats were examined by coupled morphometric and biochemical techniques. Synthetic OT was administered in doses of 0.14 and 0.25 IU/100 g/d during 7 or 10 consecutive days and the effects were followed 1, 24, 72 and 168 hours after the last injection. The function and structure of chromaffin cells were affected by the higher dose of OT only. They caused divergent responses on their amine contents. Adrenaline, noradrenaline and dopamine contents were increased, while serotonin content was decreased. These changes were different in duration and time of incidence. Stereological analysis showed an enhanced number of chromaffin cells and an increase in their total volume. The parallelism between the changes in chromaffin cell number and the catecholamine content strongly suggests a mitogenic effect of the applied OT.     

The effect of salts on catecholamine fluxes and adenosine triphosphatase activity in storage vesicles from the adrenal medulla

1. Influx and efflux of catecholamine and adenosine triphosphatase activity in storage vesicles from the adrenal medulla were studied with dl-[(14)C]adrenaline in different media. 2. The lowest values for flux and adenosine triphosphatase activity were observed in sucrose media in which an ATP-dependent influx of catecholamine compensated for an efflux of the same magnitude. Efflux in the presence or absence of ATP was similar. 3. In media containing sodium succinate or glutarate adenosine triphosphatase activity was higher and the ATP-dependent influx of catecholamine was about twice that observed in iso-osmotic sucrose medium. In the presence of ATP influx and efflux of catecholamine were balanced; in its absence there was a net release of catecholamine, since efflux was more than twice the influx. Efflux in the presence or absence of ATP was similar. 4. In media containing sodium or potassium chloride and in the presence of ATP influx and adenosine triphosphatase activity were further enhanced, but in the absence of ATP there was no further increase in influx, since catecholamine was released with or without ATP at the same rate. Efflux was therefore twice as high in the presence of ATP as in its absence. 5. Sodium nitrate suppressed the ATP-dependent influx nearly completely, but caused a greatly enhanced efflux, which was twice as high in the presence of ATP as in its absence. 6. The extinction of vesicular suspensions remained unchanged in the presence of ATP under conditions where the catecholamine efflux was balanced by the influx. Under conditions where the efflux was not compensated by influx, the extinction of the suspensions decreased in the presence of ATP more than in its absence.     

The restoration of the enzyme activity of chernozem soil after gamma-irradiation

The Influence of gamma-radiation by dozes 1, 5, 10 and 20 kGy on enzyme activity of ordinary chemozem were studied. Dynamics of the restoration of the enzyme activity after the influence of gamma-radiation in model experiments in 3, 30, 90 and 180 days was investigated. The doze 1 kGy did no statistically significant influence on the investigated enzymes. Dehydrogenase is more radiosensitive enzyme than catalase. Values of the saccharase activity differed a significant variation so in most cases it has not been registered statistically significant changes. In 90-180 days of the incubation enzymes activity was restored up to control values. Dehydrogenase activity in 180 days in variants with dozes 10 and 20 kGy was restored up to a level of the control, over variants with dozes 1 and 5 kGy--is higher than the control over 78% and 23% accordingly. Saccharase activity in 180 days after the influence of gamma-radiation with a doze 20 kGy was on 61% lower than the control.     

Tissue-type plasminogen activator in rat adrenal medulla

Rat adrenal glands were stained immunocytochemically using antibodies against plasminogen activators of the tissue-type (t-PA) and urokinase-type (u-PA). A subpopulation of the cells in the adrenal medulla showed intense cytoplasmic t-PA immunoreactivity, while no u-PA immunoreactivity was detected in any adrenal cells. Fluorescence microscopy of adjacent sections demonstrated that the cells stained for t-PA contained noradrenaline. Analysis with a histochemical fibrin slide technique demonstrated a plasminogen-dependent fibrinolysis in the adrenal medulla. SDS-PAGE of adrenal gland extracts followed by zymography established the molecular weight of this plasminogen activator to be similar to that of rat t-PA. In addition SDS-PAGE followed by immunoblotting with anti-t-PA IgG of adrenal gland extracts revealed one band with an electrophoretic mobility indistinguishable from that found in the zymography. When tissue-sections and immunoblots were incubated with antibodies absorbed with highly purified t-PA no staining was found. In view of the previous finding of t-PA in growth hormone-containing cells of the pituitary gland, these findings substantiate that t-PA can be found in the intact normal organism outside endothelial cells, and further point to t-PA having a function in endocrine cells.     

Characterization of the rat adrenal medulla cultured in vitro

Summary A wide variety of experimental animal models have been used to investigate the mechanisms of synthesis, storage, and release of catecholamines. Whereas in vivo experimental models are situated at one end of the spectrum, cell culture models are situated at the other end. In the present study, we have characterized various aspects of the rat adrenal medulla cultured in vitro as a whole tissue, aiming to establish a new experimental model in between in vivo animal models and cell culture models. We adapted a bottle rotator system commonly used for culturing rodent whole embryos. Changes in histology, activities and mRNA levels of catecholamine-synthesizing enzymes, and concentrations of catecholamines in the adrenal medulla were studied. In addition, the effects of cholinergic stimulation on catecholamine release from the adrenal medulla were examined. Overall the results indicate that various aspects of the adrenal medulla become stable after 4 d of culture and the adrenal medulla at this stage releases catecholamines in response to cholinergic stimulation. The whole adrenal medulla culture system may be a useful tool for investigating catecholamine-related functions dependent on intercellular reactions or communications.     

High-affinity angiotensin receptors in rat adrenal medulla

Angiotensin II receptors have been quantitated in single rat adrenal medullas by incubation of tissue sections with 125I-[Sar1]-AII, autoradiography with exposure to 3H-sensitive Ultrofilm, computerized densitometry and comparison with 125I-labelled standards. Rat adrenal medulla contains a single class of high affinity AII receptors with a Ka of 0.84 +/- 0.02 X 10(9) M-1 and a Bmax of 3259 +/- 502 fmol/mg protein, one of the highest densities in AII receptors found in rat tissues. These observations provide evidence for a local site of action of AII in the release of adrenal medullary catecholamines.     

Tissue-type plasminogen activator in rat adrenal medulla

Summary Rat adrenal glands were stained immunocytochemically using antibodies against plasminogen activators of the tissue-type (t-PA) and urokinase-type (u-PA). A subpopulation of the cells in the adrenal medulla showed intense cytoplasmic t-PA immunoreactivity, while no u-PA immunoreactivity was detected in any adrenal cells. Fluorescence microscopy of adjacent sections demonstrated that the cells stained for t-PA contained noradrenalin. Analysis with a histochemical fibrin slide technique demonstrated a plasminogen-dependent fibrinolysis in the adrenal medulla. SDS-PAGE of adrenal gland extracts followed by zymography established the molecular weight of this plasminogen activator to be similar to that of rat t-PA. In addition SDS-PAGE followed by immunoblotting with anti-t-PA IgG of adrenal gland extracts revealed one band with an electrophoretic mobility indistinguishable from that found in the zymography. When tissue-sections and immunoblots were incubated with antibodies absorbed with highly purified t-PA no staining was found. In view of the previous finding of t-PA in growth hormone-containing cells of the pituitary gland, these findings substantiate that t-PA can be found in the intact normal organism outside endothelial cells, and further point to t-PA having a function in endocrine cells.