Adrenocorticotropic activity in the rat assessed by in vivo and in vitro indices

1963 ◽  
Vol 205 (6) ◽  
pp. 1083-1088 ◽  
Author(s):  
J. J. Van Goch ◽  
D. De Wied ◽  
E. Schönbaum
Keyword(s):  
Ascorbic Acid ◽  
Plasma Corticosterone ◽  
In Vitro Technique ◽  
Rat Adrenals ◽  
Hypophysectomized Rats ◽  
Adrenal Corticosterone ◽  
Intact Rats

Several indices of adrenocorticotropic (ACTH) activity were compared in order to establish the index most suitable for assay purposes, particularly of ACTH in blood. In hypophysectomized rats, the effects of ACTH on adrenal ascorbic acid, cholesterol, and steroid formation in vitro were studied. In intact rats, the effects of formalin on these variables as well as on the adrenal and plasma corticosterone levels and hypophyseal and blood ACTH activity were measured. Adrenal corticosterone as well as steroid formation in vitro increased very rapidly after stimulation by ACTH. In hypophysectomized rats, after intravenous ACTH, significant increases were observed after 5 min. In normal rats, 3 min after the injection of formalin, significant increases of steroid formation in vitro and ACTH activity were observed. The in vitro technique is suitable for the study of changes in ACTH activity. ACTH increases the fraction of corticosterone found in the total amount of corticoid secreted by rat adrenals in vitro.

THE EFFECT OF PIG PITUITARY ACTH FRACTIONS ON DIFFERENT PARAMETERS OF ADRENOCORTICAL ACTIVITY

1963 ◽  
Vol 41 (6) ◽  
pp. 1455-1467 ◽  
Author(s):  
E. de Jager ◽  
J. D. H. Homan ◽  
D. de Wied
Keyword(s):  
Plasma Corticosterone ◽  
Buffer System ◽  
Adrenocortical Activity ◽  
In Vivo Assays ◽  
In Vitro Technique ◽  
Separate Fraction ◽  
Hypophysectomized Rats ◽  
Assay Methods

Purified unhydrolyzed corticotrophin was separated into five fractions by chromatography on a column of carboxymethyl cellulose, using pyridine – acetic acid as a buffer system. These fractions were biologically assayed by means of the in vitro technique of Saffran and Schally, the adrenal ascorbic acid depletion test of Sayers et al., and an assay based on the increase of plasma corticosterone levels in hypophysectomized rats. In the in vivo assays both the intravenous and subcutaneous routes of injection were applied.The principal aim of this study was to investigate for each separate fraction the extent to which the potencies according to the Sayers test correspond with the potencies obtained by the plasma corticosterone method. When comparing results found after identical routes of injection, a fair agreement was observed for those fractions showing electrophoretic relationship and together accounting for the major part of the biological activity of the starting material. However, the minor fractions showed significant differences.These findings are discussed together with the results of the classical assay methods and their deviations from data reported in the literature.

THE EFFECT OF PIG PITUITARY ACTH FRACTIONS ON DIFFERENT PARAMETERS OF ADRENOCORTICAL ACTIVITY

1963 ◽  
Vol 41 (1) ◽  
pp. 1455-1467
Author(s):  
E. de Jager ◽  
J. D. H. Homan ◽  
D. de Wied
Keyword(s):  
Plasma Corticosterone ◽  
Buffer System ◽  
Adrenocortical Activity ◽  
In Vivo Assays ◽  
In Vitro Technique ◽  
Separate Fraction ◽  
Hypophysectomized Rats ◽  
Assay Methods

Purified unhydrolyzed corticotrophin was separated into five fractions by chromatography on a column of carboxymethyl cellulose, using pyridine – acetic acid as a buffer system. These fractions were biologically assayed by means of the in vitro technique of Saffran and Schally, the adrenal ascorbic acid depletion test of Sayers et al., and an assay based on the increase of plasma corticosterone levels in hypophysectomized rats. In the in vivo assays both the intravenous and subcutaneous routes of injection were applied.The principal aim of this study was to investigate for each separate fraction the extent to which the potencies according to the Sayers test correspond with the potencies obtained by the plasma corticosterone method. When comparing results found after identical routes of injection, a fair agreement was observed for those fractions showing electrophoretic relationship and together accounting for the major part of the biological activity of the starting material. However, the minor fractions showed significant differences.These findings are discussed together with the results of the classical assay methods and their deviations from data reported in the literature.

“IN VIVO” AND “IN VITRO” EFFECT OF ASCORBIC ACID AND ACTH ON THE RAT ADRENAL CORTEX

1952 ◽  
Vol 30 (3) ◽  
pp. 157-162
Author(s):  
A. DesMarais ◽  
J. Leblanc
Keyword(s):  
Ascorbic Acid ◽  
Adrenal Cortex ◽  
Adrenal Glands ◽  
Secretory Activity ◽  
In Vitro Experiments ◽  
Hypophysectomized Rats ◽  
Vitro Effect ◽  
Histochemical Examination

Histochemical examination of adrenal glands of hypophysectomized rats given both ascorbic acid and ACTH showed an enlargement of the cortex and a decrease of sudanophilic substances, as compared to adrenals of hypophysectomized rats receiving ACTH alone. “In vitro” experiments on incubated slices of adrenal glands have shown that ascorbic acid and ACTH have a synergistic effect on the secretory activity of the cells of the adrenal cortex.

THE BIOLOGICAL ACTIVITY OF [1-D-SERINE, 17–18-DILYSINE]-β-CORTICOTROPHIN-(1-18)-OCTADECAPEPTIDE-AMIDE

1971 ◽  
Vol 68 (3) ◽  
pp. 458-466 ◽  
Author(s):  
René Maier ◽  
Pierre L. Barthe ◽  
Lotte Schenkel-Hulliger ◽  
Pierre A. Desaulles
Keyword(s):  
Ascorbic Acid ◽  
Biological Activity ◽  
Plasma Corticosterone ◽  
Maximum Plasma ◽  
Duration Of Action ◽  
Threshold Doses

ABSTRACT Compared with β-corticotrophin-(1-24)-tetracosapeptide (tetracosactide), [1-D-serine,17,18-dilysine]-β-corticotrophin-(1-18)-octadecapeptide-amide (CIBA 41,795-Ba) is a highly potent peptide in respect of its adrenal and extra-adrenal activities in the rat. The adrenal steroidogenic activity of these two peptides in vivo varies according to the parameter measured. A comparison of the threshold doses reveals that 41,795-Ba is 10 times more potent than tetracosactide, but when the doses producing equal areas under the time-curves are compared, 41,795-Ba is 100 times more potent, while the duration of action of 41,795-Ba expressed in terms of the maximum plasma corticosterone concentrations is 4 times longer than that of the same dose of tetracosactide. The octadecapeptide is about 10 times more potent than tetracosactide in its capacity to evoke steroidogenesis in vitro, in depleting the adrenals of ascorbic acid, and in its melanophore-expanding activity. Its lipolytic potency is about 3 times greater than that of tetracosactide in vitro and about 100 times greater in vivo at threshold doses. Preliminary studies in man have shown that 41,795-Ba possesses about 10 times the corticotrophic activity of tetracosactide and a longer duration of action.

PITUITARY AND ADRENAL RESPONSIVENESS IN RATS AFTER PROLONGED TREATMENT WITH ACTH

1963 ◽  
Vol 41 (1) ◽  
pp. 1771-1777
Author(s):  
E. Stark ◽  
J. Fachet ◽  
Katherine Mihály
Keyword(s):  
Prolonged Exposure ◽  
Corticosterone Level ◽  
Plasma Corticosterone ◽  
Prolonged Treatment ◽  
Plasma Corticosterone Level ◽  
Operative Trauma ◽  
Corticosterone Secretion ◽  
Adrenal Corticosterone

Prolonged exposure to ACTH considerably increased adrenal responsiveness in the rat both in vivo and in vitro. The last of 5 and 14 daily injections each produced a significantly higher blood corticosterone level than did a single injection. In the presence of ACTH added in vitro, adrenal corticosterone production in animals subjected to prolonged treatment with ACTH significantly exceeded the production per unit of weight and unit of time measured in saline-treated animals. Reduced adrenal responsiveness in the stage of resistance, elicited by formalin as a non-specific stress, cannot be invoked as an explanation for the absence of an increase in corticosterone secretion. The conclusion is that after prolonged exposure to non-specific stress there is no longer any ACTH hypersecretion.Twenty-four hours after the last injection of prolonged ACTH treatment there was inhibition of endogenous ACTH release by the pituitary gland, formalin produced no rise in the corticosterone level of the peripheral blood, and operative trauma caused substantially less ascorbic acid depletion than it did in saline-treated controls, although the plasma corticosterone level was normal or below normal.

PITUITARY AND ADRENAL RESPONSIVENESS IN RATS AFTER PROLONGED TREATMENT WITH ACTH

1963 ◽  
Vol 41 (8) ◽  
pp. 1771-1777 ◽  
Author(s):  
E. Stark ◽  
J. Fachet ◽  
Katherine Mihály
Keyword(s):  
Prolonged Exposure ◽  
Corticosterone Level ◽  
Plasma Corticosterone ◽  
Prolonged Treatment ◽  
Plasma Corticosterone Level ◽  
Operative Trauma ◽  
Corticosterone Secretion ◽  
Adrenal Corticosterone

Prolonged exposure to ACTH considerably increased adrenal responsiveness in the rat both in vivo and in vitro. The last of 5 and 14 daily injections each produced a significantly higher blood corticosterone level than did a single injection. In the presence of ACTH added in vitro, adrenal corticosterone production in animals subjected to prolonged treatment with ACTH significantly exceeded the production per unit of weight and unit of time measured in saline-treated animals. Reduced adrenal responsiveness in the stage of resistance, elicited by formalin as a non-specific stress, cannot be invoked as an explanation for the absence of an increase in corticosterone secretion. The conclusion is that after prolonged exposure to non-specific stress there is no longer any ACTH hypersecretion.Twenty-four hours after the last injection of prolonged ACTH treatment there was inhibition of endogenous ACTH release by the pituitary gland, formalin produced no rise in the corticosterone level of the peripheral blood, and operative trauma caused substantially less ascorbic acid depletion than it did in saline-treated controls, although the plasma corticosterone level was normal or below normal.

In vitro and in vivo reduction of erythrocyte sorbitol by ascorbic acid

Diabetes ◽  
1989 ◽  
Vol 38 (8) ◽  
pp. 1036-1041 ◽  
Author(s):  
J. A. Vinson ◽  
M. E. Staretz ◽  
P. Bose ◽  
H. M. Kassm ◽  
B. S. Basalyga
Keyword(s):  
Ascorbic Acid

Reduced and S-carboxymethylated human growth hormone: a probe for diabetogenic action

1984 ◽  
Vol 247 (5) ◽  
pp. E639-E644
Author(s):  
C. M. Cameron ◽  
J. L. Kostyo ◽  
J. A. Rillema ◽  
S. E. Gennick
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Mouse Mammary Gland ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Hypophysectomized Rats

The biological activity profile of reduced and S-carboxymethylated human growth hormone (RCM-hGH) was determined to establish its suitability for study of the diabetogenic property of hGH. RCM-hGH was found to have greatly attenuated in vivo growth-promoting activity in the 9-day weight-gain test in hypophysectomized rats (approximately 1%) and to have a similar low order of in vitro activity in stimulating amino acid incorporation into the protein of the isolated rat diaphragm. RCM-hGH also only had approximately 1% of the in vitro insulin-like activity of the native hormone on isolated adipose tissue from hypophysectomized rats. In contrast, RCM-hGH retained substantial in vivo diabetogenic activity in the ob/ob mouse, appearing to have approximately 50% of the activity of the native hormone. RCM-hGH was also found to retain significant, although attenuated (25%), in vitro lactogenic activity when tested for the ability to stimulate amino acid incorporation into a casein-rich protein fraction in mouse mammary gland explants. Because RCM-hGH exhibits a high degree of diabetogenic activity, although lacking significant anabolic or insulin-like activities, it will be useful as a "monovalent" probe for the study of the molecular mechanism of the diabetogenic action of GH.

Maturation, iron deficiency, and ligands in enteric radioiron transport in vitro

1963 ◽  
Vol 204 (1) ◽  
pp. 171-175 ◽  
Author(s):  
W. S. Ruliffson ◽  
J. M. Hopping
Keyword(s):  
Ascorbic Acid ◽  
Iron Deficiency ◽  
Iron Absorption ◽  
Deficiency Anemia ◽  
Anaerobic Incubation ◽  
Reverse Effect ◽  
Factors Affecting ◽  
Everted Gut Sac

The effects in rats, of age, iron-deficiency anemia, and ascorbic acid, citrate, fluoride, and ethylenediaminetetraacetate (EDTA) on enteric radioiron transport were studied in vitro by an everted gut-sac technique. Sacs from young animals transported more than those from older ones. Proximal jejunal sacs from anemic animals transported more than similar sacs from nonanemic rats, but the reverse effect appeared in sacs formed from proximal duodenum. When added to media containing ascorbic acid or citrate, fluoride depressed transport as did anaerobic incubation in the presence of ascorbic acid. Anaerobic incubation in the presence of EDTA appeared to permit elevated transport. Ascorbic acid, citrate, and EDTA all enhanced the level of Fe59 appearing in serosal media. These results appear to agree with previously established in vivo phenomena and tend to validate the in vitro method as one of promise for further studies of factors affecting iron absorption and of the mechanism of iron absorption.

Studies on the mutagenic activity of ascorbic acid in vitro and in vivo

1983 ◽  
Vol 117 (1-2) ◽  
pp. 183-191 ◽  
Author(s):  
E.P. Norkus ◽  
W. Kuenzig ◽  
A.H. Conney
Keyword(s):  
Ascorbic Acid ◽  
Mutagenic Activity
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