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PubMed1977

[Problem of thickening of the adrenal cortex in acute thermal stress].

The problem was studied on albino rats: five rats served as controls; five--were overheated in a thermochamber at 45 degrees C up to the state of motor excitation (the first series); five--up to the heat stroke (the second series). By means of cytometry it was statistically stated that the cross section area of the fascicular zone spongiocytes of the adrenal cortex in the first series decreased by 14,77% in comparison with the control. The cross section area of the adrenocorticocytes of the reticular zone in the animals of the second series decreased by 7,91%. The vascular reaction of the adrenal cortex in the animals of the first series was manifested in hyperemia, which increased in animals of the second series. Hence, the adrenal cortex thickness is the result of blood congestion rather than derived from real hypertrophy; an abrupt vasodilatation disturbs the parallelism in spongiocytes arrangement, that gives a semblance that the thickness of the reticular cortex zone goes at the expense of the fascicular zone.

Acute Disease↗
PubMed1976

Fat distribution in the adrenal cortex as an indication of the mode of intrauterine death.

The presence of fat in the fetal zone of the adrenal cortex in the stillborn macerated fetus is indicative of the mode of intrauterine death. Three basic patterns are recognized. In the type I pattern there is only a scant amount of fat, close to the medullary zone. In the type II pattern fat is more widespread and is present in many more cells of the fetal zone. The type III pattern reflects a massive fatty change of almost all cells throughout the fetal cortical zone. Correlation of the three fat patterns with the pathology of the placenta and clinical data relevant to the etiology of intrauterine death has led to the following conclusions. The type I fat pattern is indicative of an acute mode of death, the type II pattern is indicative of a more prolonged period of intrauterine deterioration prior to death, whereas the type III pattern is indicative of a chronic mode of death. Determination of the fat patterns in the fetal zone of the adrenal cortex can be helpful when the clinician is confronted with the problem of fetal death, especially when maceration may hamper more detailed pathologic studies.

Adrenal Cortex↗
PubMed1989

Mechanism of action of serotonin on frog adrenal cortex.

The mechanism of action of serotonin (5-HT) on frog adrenal cortex has been investigated in vitro using the perifusion system technique. The direct effect of 5-HT on corticosteroid secreting cells was demonstrated, using enzymatically dispersed adrenocortical cells. Melatonin and 5-HTP appeared to be less potent than 5-HT to enhance corticosteroid secretion. In contrast Trp and 5-HIAA were totally devoid of effect on steroid secretion. To investigate the type of receptor involved in the stimulatory effect of 5-HT on adrenocortical cells, adrenal slices were stimulated with 5-HT in absence or presence of various antagonists. We observed that classical antagonists of 5-HT1, 5-HT2 and 5-HT3 type receptors failed to block 5-HT-induced corticosteroid secretion in our model. These results show that 5-HT exerts a direct effect on corticosteroid-secreting cells. Our data also indicates that the type of receptor involved in the action of 5-HT in frog adrenal cortex differs from mammalian 5-HT receptors.

5-Hydroxytryptophan↗
PubMed1975

Mitochondrial structure in the rat adrenal cortex.

Two distinct classes of mitochondria are described in the normal adrenal cortex of the Sprague Dawley CFY rat. Polyaminar mitochondria were frequently observed in the zona fasciculata and zona reticularis, particularly after ACTH stimulation of the cortex resulting from cold-stress exposure. It is uncertain whether such organelles are degenerating forms, or whether they have a specific functional role related to steroidogenesis in the normal cortical cell. In both normal and stressed adrenal cortices, protrusions of the outer membrane of mitochondria were evident, and were often seen penetrating lipid droplets. It is suggested that these protrusions may have some significance in the transport of cholesterol from the lipid droplet to the inner mitochondrial memrane 'desmolase complex', thus facilitating side-chain cleavage of cholesterol to pregnenolone.

Adrenal Cortex↗
PubMedDate not supplied

[Dynamics of lipid peroxidation and steroidogenesis in adrenal cortex during stress].

The phase character of lipid peroxidation has been found in the rabbit adrenal cortex in the process of adaptation to extreme loads. Under acute stress the activation of lipid peroxidation is directly dependent on the hormonal synthesis processes. Under conditions of the prolonged stress factor an enhancement of the lipid peroxidation intensity in the adrenal cortex coincides with a decrease in the steroidogenesis rate.

11-Hydroxycorticosteroids↗
PubMed1982

Effect of thyroidectomy on pregnenolone and progesterone biosynthesis in rat adrenal cortex.

The effects of thyroidectomy on pregnenolone and progesterone biosynthesis were investigated in rat adrenal cortex mitochondria and microsomes. The sequential hydroxylations of cholesterol, and the latter's side-chain cleavage, which constitute the limiting step in steroidogenesis, were studied by measuring oxygen consumption rates in the presence of cholesterol derivatives. The addition of (20R)-hydroxycholesterol, (22R)-hydroxycholesterol or (20R,22R)-dihydroxycholesterol stimulated these rates, but addition of cholesterol or (22S)-hydroxycholesterol had little effect. Thyroidectomy significantly reduced oxygen consumption rates in the presence of the sterols by about 30%. Oxygen uptake was small in the presence of respiratory inhibitors; the addition of sterols raised this uptake but subsequent thyroidectomy did not change it. Rat adrenal cortex mitochondria and microsomes converted pregnenolone ino progesterone through 3 beta ol dehydrogenase/delta 4-5 isomerase, in two different successive steps. Values for enzyme activities were 0.18, 0.26 and 0.81 nmol progesterone/min/mg protein for the overall complex, the 3 beta ol dehydrogenase and the delta 4-5 isomerase respectively. All enzyme activities were unchanged by thyroidectomy. Similar results were obtained for corresponding microsomal activities whose values were in the same range. For both microsomes and mitochondria, the dehydrogenase reaction was the limiting step in the enzyme reaction leading to progesterone formation from pregnenolone. The limiting step in corticosteroidogenesis leading to prenenolone formation by an NADPH-dependent step was slowed down by thyroidectomy, probably because the reaction that transfers energy from NADH to NADP was inhibited. The enzyme complex leading to progesterone which involves NAD+ as cofactor, was unchanged by thyroidectomy. Thyroid hormones may therefore affect the availability of the energy mechanisms connected with the proton motive force, since thyroidectomy reduces both the phosphorylative oxidation and energy-dependent hydroxylation reactions involved in steroidogenesis.

Adrenal Cortex↗
PubMed1995

Neuropeptide Y modulates the sensitivity of the rat adrenal cortex to stimulation by ACTH.

Neuropeptide Y (NPY) has been identified in nerves supplying the adrenal cortex of several mammalian species, although its function in this tissue is unknown. The present studies, employing adrenocortical cells prepared by collagenase digestion, have shown that NPY, in the absence of other stimulants, has no effect on steroid secretion by the rat adrenal over a range of peptide concentrations (10(-11) to 10(-6) mol/l). However, in the presence of physiological concentrations of ACTH, which are submaximal for the stimulation of aldosterone secretion, NPY (10(-6) mol/l) significantly enhanced the secretion rate of aldosterone by rat zona glomerulosa cells in response to ACTH. This effect was specific to the rat zona glomerulosa as NPY had no effect on the response to ACTH in rat zona fasciculata cells. The effect of NPY appears to be biphasic, however, as NPY significantly attenuated the steroidogenic response to supramaximal ACTH concentrations: in rat zona glomerulosa cells the aldosterone response to 10(-8) mol ACTH/l was significantly inhibited by NPY. The effect of NPY on the ACTH response appeared to be mediated by changes in the cAMP response. NPY had no effect on the steroidogenic response to potassium ions (K+), but enhanced the response to angiotensin II. NPY (10(-6) mol/l) significantly stimulated inositol 1,4,5-trisphosphate (InsP3) production although this concentration of peptide had no effect on steroid secretion. The effects of NPY on InsP3 production were additive with those of angiotensin II. These results suggest that the role of NPY in the adrenal cortex may be to regulate the sensitivity of the zona glomerulosa to peptide stimulation.

Adenylyl Cyclases↗
PubMed1995

Modulation of 2-oxoglutarate dehydrogenase and oxidative phosphorylation by Ca2+ in pancreas and adrenal cortex mitochondria.

The effect of external free Ca2+ ([Ca2+]ex) on the 2-oxoglutarate dehydrogenase (2-OGDH) activity and the rate of state 3 respiration was studied in dog pancreas and adrenal cortex mitochondria. A method for the preparation of mitochondria from pancreas, free of zymogen granules, was developed. The mitochondria showed high respiratory control values and maintained adequate ADP/O ratios in the course of several hours. Half-maximal stimulation (K0.5) of 2-OGDH activity and state 3 respiration by Ca2+ was decreased twofold by spermine, in both pancreas and adrenal cortex mitochondria incubated with Mg2+; Na+ increased the K0.5 value for Ca2+ in both kinds of mitochondria. The matrix Ca2+ content was enhanced by spermine at different [Ca2+]ex. The Ca2+ gradient ([Ca2+]m/[Ca2+]ex) determined in Fluo 3-loaded pancreas mitochondria was found to be below 1, either in the presence of Na+ or in the absence of spermine. The protonmotive force was increased by 1 microM Ca2+, in state 3 conditions, by 6-8 mV; lower Ca2+ concentrations kept the H+ gradient rather constant. An increase in the spermine/Mg2+ ratio at constant external Ca2+ resulted in stimulation of the 2-OGDH activity and state 3 respiration. The data indicate that matrix Ca2+ may regulate the rate of ATP synthesis in pancreas and adrenal cortex mitochondria, through the modulation of 2-OGDH and the maintenance of a high H+ gradient. In addition to changes in external Ca2+, the variation in the spermine/Mg2+ ratio may also exert control of oxidative phosphorylation.

Adrenal Cortex↗
PubMed1993

[The diagnostic and therapeutic strategies in neoplasms of the adrenal cortex: the authors' own experience].

The Authors report their limited series of neoplasms of the adrenal cortex, and underline the decisive role of the modern diagnostics based on imaging techniques (US--TC--NMR). These, in fact, often allow a good definition also in the non-functioning adrenal masses incidentally discovered (incidentalomas). The authors emphasize the high quality of such diagnostic methods offering a good reliability in discriminating the nature of the adrenal mass. These undeniable diagnostic advantages have a positive impact on the surgical strategy, allowing together with a careful morphological study of the lesion, to program in detail possible demolitive operations. The authors finally underline the importance of the surgical access: they are persuaded the best is the bilateral under-rib incision. This surgical approach assures a complete exploration of the abdominal and pelvic cavity; moreover, it allows to face every complication.

Adenoma↗
PubMed1990

Autotransplantation of the adrenal cortex into the spleen of dogs.

The factors involved in regeneration of the autotrasplanted adrenal cortex were studied experimentally in dogs. On the basis of a number of conditions necessary for the regeneration of adrenocortical tissue, the dogs were divided into 4 groups according to differences in substitution therapy following autotransplantation. The only group to demonstrate long-term survival received an intermittent substitution of cortisone acetate after the completion of 6 days postoperative replacement therapy. The hormonal functions after adrenocortical autotransplantation were examined in the long-term survivers. The secretory function of adrenocortical tissue after autotransplantation was confirmed by the detection of serum concentrations of aldosterone and cortisol, however, estrogens were not detected in the peripheral blood stream following autotransplantation. The negative response to the synthetic ACTH stimulation test observed in this study was evidence of the functional limitation of regenerated cortical tissue. Clinically, however, the procedure performed in this study will be beneficial for patients with advanced and metastatic breast cancer, not only as a form of surgical hormonal therapy, but also as an effective palliative method of treatment.

Adrenal Cortex↗
PubMed1987

Immunogold cytochemistry of cytochromes P-450 in porcine adrenal cortex. Two enzymes (side-chain cleavage and 11 beta-hydroxylase) are co-localized in the same mitochondria.

In order to study the distribution of mitochondrial cytochromes P-450 in porcine adrenal glands, the glands of anesthetized pigs were fixed in situ. Polyclonal antibodies against two cytochromes P-450, i.e., C27 side-chain cleavage enzyme and 11 beta-hydroxylase, were used to study the distribution of these enzymes in cryosections of the adrenal cortex. Ultrathin cryosections were evaluated by both protein-A/gold/silver immunocytochemistry and immunoelectron microscopy using double labeling with protein-A/colloidal-gold. At light microscopy, the two cytochrome P-450 enzymes were found to be broadly distributed in both the fasciculata and glomerulosa zones of the adrenal cortex. Quantitative immunoelectron microscopy revealed that both enzymes were localized only in mitochondria, in which they were present on the inner aspects of the inner mitochondrial membrane. Both cytochromes P-450 were demonstrable in all of the mitochondria examined, and statistical evaluation of the ratios of the two enzymes present in individual mitochondria yielded a normal distribution curve. Since no evidence was found for the preferential localization of either enzyme in a special population of mitochondria, we conclude that all mitochondria of the adrenal cortex contain both enzymes. We discuss implications of these findings with respect to the regulation of steroidogenesis.

Adrenal Cortex↗
PubMed1990

An ultrastructural stereologic study of mitochondria in the neonatal adrenal cortex of the rat.

The ultrastructural changes observed during the neonatal period of the rat adrenal cortex are described. The zona juxta-medullaris cells presented round mitochondria with vesicular cristae and large endoplasmic reticulum. Variations on the surface of the mitochondrial cristae were determined by morphometric methods. The cortical cells of 1 and 10-days-old rats showed a well developed endoplasmic reticulum. Morphological analysis indicate that the number of mitochondrial cristae increase the third day, followed by a decrease. At the tenth day a second increase was observed. Plasma corticosterone was also measured. The highest levels of this hormone were found in the 1, 2 and 10-days-old rats. A decrease was observed in rats of 3 to 8 days of age. This result is coincident with the adrenal changes observed in the developing of mitochondria and endoplasmic reticulum in the neonatal period. The increase in the number of mitochondrial cristae in the three-days old rats can be considered a morphological expression of the neonatal gland in the period influenced by maternal dependence. The most important morphological and metabolic changes observed the second week of life are probably due to the maturation of the hypothalamic pituitary axis that stimulates the neonatal adrenal cortex secretion, which is independent of maternal dependence.

Adrenal Cortex↗