The effects of monensin on Golgi complex of adrenal cortex and steroidogenesis

The ultrastructural and biochemical changes produced by monensin on zona fasciculata cells of the rat adrenal cortex are described. In this study we used adrenal cells in culture, adrenal slices and the intact animal. Monensin (1 microM) was added to the culture medium containing the cells, and to the incubation medium containing the adrenal slices, and was injected intravenously to the intact animal (0.65 mg/kg body weight). The ultrastructural alterations were similar in the three experimental conditions, and consisted of Golgi complex disorganization with dilated cisternae or large smooth vesicles. Quantitative analysis showed a significant increase of the relative volume of the Golgi area. The biochemical study demonstrated a significant decrease of corticosterone concentrations in culture medium after monensin addition, and in adrenal glands from treated rats. These results showed that monensin alters the fine structure of adrenal cortex Golgi complex and inhibits corticosteroidogenesis, which supports the probable role of the Golgi complex in the regulation of steroidogenesis.

A correlated morphological and biochemical study on the rat adrenal steroidogenesis

The ultrastructural and biochemical alterations produced by an hypocholesterolemic drug, 17 alpha-ethinyl estradiol, on the rat adrenal cortex were studied. Male rats aged two months and with approximately 200 g in weight were injected subcutaneously with 10 mg/kg/day of ethinyl estradiol during 9 days; rats injected with 1 ml propylene glycol were used as controls. The animals were sacrificed on the 10th day, and the adrenals from some of them were processed for electron microscopy. The adrenals from the remaining rats were used for measurements of the glands cholesterol and corticosterone, which were also measured in the blood. In estradiol-treated rats the zona fasciculata cells exhibited numerous microvilli, increase in the size of mitochondria and decrease in the number of lipid droplets. The quantitative analysis showed a significant increase of the volumetric density of mitochondria and microvilli and a significant decrease of the lipid droplets in the treated rats, when compared with normal ones. In treated rats, the concentration of cholesterol and corticosterone in the gland and blood were significantly decreased. These data show that hypocholesterolemia produced by estradiol has a remarkable effect on adrenal steroidogenesis, depletes the pool of adrenal cholesteryl esters, and evidences the role of plasma cholesterol in the corticosteroidogenesis.

RNA synthesis inhibitors on young rat adrenal in primary culture. An ultrastructural study

Adrenal cells of newborn rat adrenals in primary tissue culture were treated with actinomycin D (2, 10 and 25 micrograms/ml), alpha-amanitin (5 and 50 micrograms/ml) and cordycepin (100 micrograms/ml) and studied with the electron microscope. The most striking changes observed with the three drugs were localized on the nucleoli, and consisted, respectively, of segregation (actinomycin D), fragmentation (alpha-amanitin) and microsegregation (cordycepin). These results are consistent with the molecular sites of action of the drugs and are comparable to previous in vivo findings.

Ultrastructural and biochemical alterations produced in rat adrenal cortex by 4-aminopyrazolopyrimidine

The ultrastructural and biochemical changes produced by 4-aminopyrazolo[3,4-d]pyrimidine (4-APP), on zona fasciculata cells of rat adrenal cortex are described. Male rats weighing approximately 200 g were injected intraperitoneally with 50 mg/kg/day of 4-APP for 3 days; the controls were injected with buffer. All animals were sacrificed on the 4th day and the adrenals from some of them were processed for electron microscopy. The adrenals from the remaining rats were used for measurements of gland cholesterol and corticosterone; the latter was also measured in the blood. In 4-APP-treated rats the zona fasciculata cells exhibited an increase in the amount of smooth endoplasmic reticulum and in the number of free ribosomes, often arranged in polyribosomes, and a decrease in the number of lipid droplets. The nucleus showed scarce condensed chromatin and nucleolar fragmentation. The quantitative analysis showed a significant increase of the volumetric density of endoplasmic reticulum and a significant decrease of the lipid droplets in treated rats when compared with controls. Concerning the nucleus, the volumetric density of condensed chromatin significantly decreased, while the relative volume of fibrillar centers, and of granular and vacuolar components increased. In treated rats, the adrenal cholesterol and corticosterone concentrations and the blood corticosterone level were significantly decreased. These data show that 4-APP has a remarkable effect on corticosteroidogenesis and depletes the pool of adrenal cholesteryl esters, and these data stress the importance of plasma cholesterol in the steroidogenesis; on the other hand the drug appears to have a direct effect on the nucleus.