THE METABOLISM OF MUCOPOLYSACCHARIDES: III. THE EFFECT OF ADRENOCORTICAL HORMONES ON ENZYMES INVOLVED IN GLUCURONIDE SYNTHESIS AND METABOLISM IN CONNECTIVE TISSUE

1967 ◽  
Vol 45 (8) ◽  
pp. 1245-1253 ◽  
Author(s):  
T. S. Foster
Keyword(s):  
Connective Tissue ◽  
Replacement Therapy ◽  
Enzyme Activities ◽  
Glucuronic Acid ◽  
Hormone Treatment ◽  
Adrenocortical Hormones ◽  
Adrenalectomized Rats

The levels of activity of hexokinase, phosphoglucomutase, uridine diphosphoglucose pyrophosphorylase, and uridine diphosphoglucose dehydrogenase, which are involved in the synthesis of glucuronic acid, and the levels of glucuronosyltransferase and β-glucuronidase, which are involved in its metabolism, were studied in connective tissue from polyvinyl sponge implants from sham-operated and adrenalectomized rats which had received "replacement therapy" of individual steroids.The levels of activity of these enzymes were significantly increased in sham-operated rats which had been treated with corticosterone, cortisone, or hydrocortisone. In adrenalectomized animals, the increased or decreased enzyme activities were restored to normal levels by "therapy" with corticosterone, cortisone, or hydrocortisone. In some cases there was an over-correction at the particular level of hormone treatment. In both sham-operated and adrenalectomized animals, treatment with deoxycorticosterone, progesterone, or Reichstein's substance S frequently, but not always, resulted in little or no change in activity of the enzymes.

THE METABOLISM OF MUCOPOLYSACCHARIDES: II. THE EFFECT OF ADRENALECTOMY ON ENZYMES INVOLVED IN GLUCURONIDE SYNTHESIS AND METABOLISM IN CONNECTIVE TISSUE

1965 ◽  
Vol 43 (9) ◽  
pp. 1417-1425 ◽  
Author(s):  
T. S. Foster
Keyword(s):  
Connective Tissue ◽  
Glucuronic Acid ◽  
Sesame Oil ◽  
The Other ◽  
Hexokinase Activity ◽  
Sham Injection ◽  
Glucuronosyl Transferase ◽  
Adrenalectomized Rats

The levels of activity of hexokinase, phosphoglucomutase, uridine diphosphoglucose pyrophosphorylase, and uridine diphosphoglucose dehydrogenase, which are involved in the synthesis of glucuronic acid, and the activities of glucuronosyl transferase and β-glucuronidase, which are involved in its metabolism, were studied in connective tissue from sham-operated and adrenalectomized rats. Adrenalectomy resulted in a significant decrease in phosphoglucomutase activity and in significant increases in the activities of hexokinase, uridine diphosphoglucose dehydrogenase, and β-glucuronidase. Adrenalectomy had no effect upon the activities of uridine diphosphoglucose pyrophosphorylase or glucuronosyl transferase.The added stress of either a sham injection or injection of sesame oil, both given daily and intraperitoneally, resulted in a significant increase in hexokinase activity and a decrease in glucuronosyl transferase and β-glucuronidase activities, in both sham-operated and adrenalectomized animals. The other enzymes were unaffected.

PITUITARY AND BLOOD CORTICOTROPHIN CHANGES IN ADRENALECTOMIZED RATS MAINTAINED ON PHYSIOLOGICAL DOSES OF CORTICOSTEROIDS

1962 ◽  
Vol 39 (1) ◽  
pp. 79-86 ◽  
Author(s):  
J. R. Hodges ◽  
Joan Vernikos-Danellis
Keyword(s):  
Ascorbic Acid ◽  
Pituitary Gland ◽  
Replacement Therapy ◽  
Daily Treatment ◽  
Mild Stress ◽  
Acid Control ◽  
Small Doses ◽  
Response To Stress ◽  
Adrenalectomized Rats

ABSTRACT Pituitary and blood corticotrophin (ACTH) concentrations were estimated in adrenalectomized rats maintained on cortisol or crude adrenocortical extract (ACE) with and without ascorbic acid. Blood ACTH levels were also determined in similarly treated animals after subjection to mild stress. Thirty days after adrenalectomy there were marked rises in pituitary and blood corticotrophin concentration which were prevented by daily treatment with small doses of cortisol or ACE. In contrast to intact animals, adrenalectomized rats exhibited markedly increased adrenocorticotrophic responses to mild stress. This pituitary hyperexcitability was not diminished by replacement therapy with corticoids alone but was considerably reduced by ascorbic acid given in conjunction with ACE. It is suggested that corticoids control the rate at which ACTH is synthesised in the pituitary gland and that other factors, including ascorbic acid, control the excitability of the pituitary gland in its adrenocorticotrophic response to stress.

scholarly journals Enzymic transfer of glucose and xylose from uridine diphosphate glucose and uridine diphosphate xylose to bilirubin by untreated and digitonin-activated preparations from rat liver

1972 ◽  
Vol 129 (3) ◽  
pp. 619-633 ◽  
Author(s):  
J. Fevery ◽  
P. Leroy ◽  
K. P. M. Heirwegh
Keyword(s):  
Enzyme Activities ◽  
Metal Ion ◽  
Glucuronic Acid ◽  
Uridine Diphosphate ◽  
No Formation ◽  
Cell Extracts ◽  
Straight Line ◽  
Standard Assay ◽  
Diphosphate Glucose ◽  
Liver Homogenates

1. Digitonin-treated and untreated homogenates, cell extracts and washed microsomal preparations from liver of Wistar R rats are capable of transferring sugar from UDP-glucose or UDP-xylose to bilirubin. No formation of bilirubin glycosides occurred with UDP-galactose or d-glucose, d-xylose or d-glucuronic acid as the sources of sugar. 2. Procedures to assay digitonin-activated and unactivated bilirubin UDP-glucosyltransferase and bilirubin UDP-xylosyltransferase were developed. 3. In digitonin-activated microsomal preparations the transferring enzymes had the following properties. Both enzyme activities were increased 2.5-fold by pretreatment with digitonin. They were optimum at pH6.6–7.2. Michaelis–Menten kinetics were followed with respect to UDP-glucose. In contrast, double-reciprocal plots of enzyme activity against the concentration of UDP-xylose showed two intersecting straight-line sections corresponding to concentration ranges where either bilirubin monoxyloside was formed (at low UDP-xylose concentrations) or where mixtures of both the mono- and di-xyloside were synthesized (at high UDP-xylose concentrations). Both enzyme activities were stimulated by Mg2+; Ca2+ was slightly less, and Mn2+ slightly more, stimulatory than Mg2+. Of the activities found in standard assay systems containing Mg2+, 58–78% (substrate UDP-glucose) and 0–38% (substrate UDP-xylose) were independent of added bivalent metal ion. Double-reciprocal plots of the Mg2+-dependent activities against the concentration of added Mg2+ were linear. 4. In comparative experiments the relative activities of liver homogenates obtained with UDP-glucuronic acid, UDP-glucose and UDP-xylose were 1:1.5:2.7 for untreated preparations and 1:0.29:0.44 after activation with digitonin. 5. Bilirubin UDP-glucuronyltransferase was protected against denaturation by human serum albumin, whereas bilirubin UDP-xylosyltransferase was not. 6. Digitonin-treated and untreated liver homogenates from Gunn rats were inactive in transferring sugar to bilirubin from UDP-glucuronic acid (in agreement with the work of others), UDP-glucose or UDP-xylose.

Enzyme activities involved in connective tissue metabolism in the skin of tight-skin (TSK) mice

1986 ◽  
Vol 278 (6) ◽  
pp. 510-512 ◽  
Author(s):  
H. Shikata ◽  
M. Hiramatsu ◽  
M. Kashimata ◽  
M. Noguchi ◽  
T. Masumizu ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Enzyme Activities ◽  
Tissue Metabolism ◽  
Tight Skin ◽  
Connective Tissue Metabolism

Effect of adrenalectomy on the regulation of the secretion of gonadotrophins and prolactin in the lactating rat

1983 ◽  
Vol 98 (2) ◽  
pp. 227-232 ◽  
Author(s):  
P. van der Schoot ◽  
W. J. de Greef
Keyword(s):  
Plasma Levels ◽  
Inhibitory Action ◽  
Adrenal Glands ◽  
Marked Effect ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Blood Levels ◽  
Adrenal Hormones ◽  
Adrenocortical Hormones ◽  
Adrenalectomized Rats

The suckling stimulus exerts an inhibitory action on the release of gonadotrophins during lactation. The possible involvement of the adrenal glands in this process was examined by studying the plasma levels of gonadotrophins in lactating rats ovariectomized on the day after parturition. It appeared that the suppression, throughout suckling, of the rise in levels of gonadotrophins in blood after ovariectomy occurred to the same extent in adrenalectomized and in sham-operated animals. It thus seems unlikely that adrenocortical hormones, albeit secreted in larger quantities during lactation, exert an inhibitory effect on the release of gonadotrophins. Adrenalectomy had a marked effect on the plasma concentrations of prolactin during the second half of lactation. Whereas plasma concentrations of prolactin in the first half of lactation were similar in adrenalectomized and sham-operated rats, the concentrations in adrenalectomized rats did not undergo the reduction found in sham-operated rats. Adrenal hormones may thus be involved in the reduction of blood levels of prolactin observed in rats and in other mammals as lactation progresses.

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