Monolayer cultures of trypsin-dispersed cells of the rat adenohypophysis were grown for 5 to 54 days. ACTH was localized by immunocytochemistry using an antiserum to synthetic ACTH1-28 prepared in rabbit and sheep anti-goat immunoglobulin coupled with peroxidase. ACTH content of the culture medium was measured by radioimmunoassay. Corttion time. The corticotrophs retained their essential morphological characteristics. Immunological staining was found in the secretory granules, some tubular or saccular structures, parts of the rough endoplasmic reticulum, and the cytoplasmic matrix. Immature secretory granules in the Golgi apparatus as well as some Golgi elements showed different degrees of immunoreactivity. In agreement with the high ACTH content of the culture medium the number, size and shape of the secretory granules, the active Golgi apparatus, the high amount of extragranular ACTH as well as pictures suggesting granule extrusion claim for a high ACTH synthesis and transport (and low ACTH storage) in the cultured corticotrophs.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

The effects of cholera toxin on the adrenal weight in hypophysectomized rats.

The effects of cholera on adrenal weight in hypophysectomized rats were investigated, in an attempt to demonstrate an ACTH-like, adrenal trophic effect of the toxin. The results suggested that the toxin probably exerts is ACTH-like action on the adrenal via adenylate cyclase. Cholera toxin was also shown to have a thermolytic action, similar to that of ACTH, probably due to stimulation of adrenal glucocorticoid secretion.

Adrenal Glands↗

PubMedDate not supplied

ACTH release in rats after removal of the medial hypothalamus.

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Adrenal Glands↗

PubMedDate not supplied

Chronic stress impairs oxidative metabolism and hepatic excretion of model xenobiotic substrates in the rat.

Traumatic injury to both hard and soft tissue has been associated with a decrease in the rate of hepatic drug metabolism. The mechanism(s) underlying this phenomenon have yet to be determined, but may involve substances released from damaged tissues or activation of the adrenocortical axis secondary to stress. To determine whether a generalized stress response is involved in the trauma-induced perturbations of xenobiotic metabolism, rats were exposed to atraumatic stress for a period of 21 days prior to determining the disposition of antipyrine (an in vivo marker for the hepatic mixed-function oxidase system) and indocyanine green (a tricarbocyanine dye often used as an in vivo marker of active hepatic uptake). Exposure to stress resulted in a significant decrease in the systemic clearance of antipyrine, suggesting a stress-induced inhibition of hepatic oxidation. In addition, the stressed animals evidenced a decreased rate of uptake of indocyanine green by the liver, an apparent decrease in the storage of the dye within the liver, and a decreased hepatic clearance of indocyanine green (presumably due to a decrease in the KM for biliary transport). These observations suggest that atraumatic stress affects several processes involved in the hepatobiliary disposition of xenobiotics.

Animals↗