Subcellular distribution of calcium in zona fasciculata cells of the rat adrenal cortex

Zona fasciculata cells from the adrenal cortex of female Sprague-Dawley rats were fixed by immersion in potassium pyroantimonate-osmium tetroxide and potassium pyroantimonate-glutaraldehyde to study the distribution of calcium. Potassium pyroantimonate-osmium tetroxide treatment gave reproducible patterns of electron-opaque precipitate, whereas inconsistent deposits of reaction product were seen after potassium pyroantimonate-glutaraldehyde fixation. Nuclei showed sparse precipitate over heterochromatin and dense aggregates over areas of nucleoli surrounded by portions of the nucleolar-dense component. Two major cytoplasmic sites of precipitate were identified: mitochondria and vesicles of smooth endoplasmic reticulum. Most of the intramitochondrial precipitate was localized to the intracristal space. Precipitate was also seen in vesicles of Golgi apparatus. The extracellular space was filled with closely packed electron-opaque particles. Observation of tissues treated with control fixative saturated with EGTA showed little if any reaction, confirming that calcium was the primary cation precipitated by potassium pyroantimonate. Our results provide a method suitable for accurate localization of calcium in adrenocortical cells.     

Catecholaminergic innervation of the rat adrenal cortex

Summary The zona glomerulosa of the rat adrenal gland is innervated by catecholaminergic nerves. Using histofluorescence techniques, we observed catecholaminergic plexuses surrounding adrenal capsular and subcapsular blood vessels. Individual varicose nerve fibers that branched off these plexuses were distributed among adrenal glomerulosa cells. This innervation was permanently eliminated after neonatal sympathectomy with guanethidine or 6-hydroxydopamine, but was not affected by ligation of the splanchnic nerve or extirpation of the suprarenal ganglion. At the ultrastructural level, axonal varicosities were commonly observed in close proximity to glomerulosa cells and blood vessels. Nerve fibers and varicosities were found to contain small (30–60 nm) clear vesicles as well as large (60–110 nm) and small (30–60 nm) dense-cored vesicles. In tissue fixed for the dichromate reaction with or without pretreatment with the false transmitter 5-hydroxydopamine, many nerve terminals contained numerous small dense-cored vesicles which are thought to contain catecholamines. These results establish the anatomical substrate for the catecholaminergic innervation of the rat adrenal cortex.     

Ornithine decarboxylase activity in regenerating rat adrenal cortex

The activity of ornithine decarboxylase during the regenerating process of adrenal cortex was evaluated in Sprague-Dawley male rats weighing 140–180 g. In this study, 4 groups of rats were enucleated and another 4 groups were sham operated. Animals were maintained at a temperature of 23 ± 1°C and 12:12 h light:dark cycle. At 7 and 11 days post surgery, animals were sacrificed at 0600 h and 1800 h, respectively. Adrenal glands were immediately removed and assayed for ornithine decarboxylase (ODC). The enzyme activity was found to be significantly elevated in enucleated groups as compared to the sham control groups at the 7th and the 11th day of surgery. ODC activity was found to be about 2 times higher at 1800 h by the 7th day and 5 times higher at 1800 h by the 11th day of adrenal surgery when compared to the activity at 0600 h. From these results, it appears that ODC activity not only increases as the regeneration process of adrenal cortex approaches completion, but also becomes more pronounced towards the end of the light period.     

The fine structure of the newborn rat adrenal cortex

Summary The structural changes of the zona juxtamedullaris of the rat adrenal cortex at birth, have been examined by the light and the electron microscope. In this zone clusters of medullary cells lying among the strands of cortical tissue were observed. In the inner portion of the zona juxtamedullaris two types of adrenocortical cells were found: light and very-dark cells. The latter are smaller than the light cells and are always in close connection with the medullary tissue. The ultrastructural features of the very-dark cells suggest that these elements are in degeneration. This finding supports the hypothesis that at birth there is a partial degeneration of the rat zona juxtamedullaris, i.e. the zone corresponding to the fetal zone of some mammalian species.It is proposed that in all mammalian species at birth there is a partial regression of the zona juxtamedullaris and that the regression of the fetal zone is only the quantitative increase of this phenomenon. This hypothesis is discussed in relation to numerous data demonstrating that there are enzymatic conditions in the rat during fetal life, which permit a discrete hypertrophy of the adrenal cortex.The author wishes to express his appreciation to Dr. A. Gambino and to Mr. G. Gottardo for technical assistance.     

Genetic analysis of the distribution of corticosterone-containing cells in mouse adrenal cortex

Strains A/J and C57BL/6J (B6) differ in susceptibility to many neoplasms and infectious agents, with B6 mice generally being more resistant. Glucocorticoids protect against some of these pathologies. We examined the distribution of adrenocortical corticosterone (CS), the major endogenous glucocorticoid in mice, in these strains, using anti-CS serum. A distinct strain difference was found. B6 adrenals exhibited abundant CS-positive cells in cord-like arrays while A/J adrenals contained fewer, randomly arranged CS-positive cells. To quantify these results, each adrenal cortex was divided into eight sectors and each sector was classified as to phenotype. Ninety-three percent of the sectors of B6 cortices exhibited the cord-like pattern, whereas only 15% of the sectors of A/J cortices exhibited this pattern. These differences are consistent with a hypothesis that A/J mice are relatively deficient in the prophylactic activities of endogenous glucocorticoids. Adrenal glands from (C57BL/6J x A/J)F1 hybrid mice had approximately equal proportions of areas exhibiting each phenotype, indicating codominant alleles for this trait. We propose the name Cor for this gene. Thirty AXB and BXA recombinant inbred (RI) lines of mice derived from A/J and B6 progenitors were examined for CS immunostaining. Twenty-eight of them had either predominantly A/J-like or predominantly B6-like phenotypes. These RI data support either of two hypotheses. Hypothesis 1 emphasizes the nearly complete concordance of the RI lines with progenitor phenotypes and proposes that a single Cor gene regulates the distribution of CS-positive cells. Using this model, the strain distribution among RI lines implies linkage of Cor to a region on chromosome 6, 27-37 cM from the centromere. Hypothesis 2, which gives greater weight to the two RI lines with intermediate numbers of CS-positive cells, postulates an epistatic interaction between two Cor loci.