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Results for “CARBOHYDRATE METABOLISM”

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At least 19 recordsLinked to original sources
PubMed1985

The effects of long-acting injectable contraceptives on carbohydrate metabolism.

Carbohydrate metabolism, as assessed by the intravenous glucose tolerance test (i.v.-GTT), was studied in 19 healthy, non-lactating women who received injectable contraceptives containing either medroxyprogesterone acetate (DMPA) (10 subjects) or norethisterone enanthate (Net-En) (9 subjects). Tests were made prior to treatment and at intervals over a period of 15 months thereafter. Results obtained indicate that carbohydrate metabolism is not impaired by either of the two progestogens, and neither pyruvate nor cortisol concentrations changed significantly over the period of observation. However, the insulin release in response to glucose loading underwent interesting alterations during treatment. These abnormalities returned promptly to normal after withdrawal of treatment.

Adult↗
PubMed1976

Influence of oral contraceptives, pyridoxine (vitamin B6), and tryptophan on carbohydrate metabolism.

Carbohydrate metabolism and vitamin-B6 status were assessed before and after pyridoxine administration in 46 women taking combined oestrogen-progestagen oral contraceptives (O.C.). 18 women had evidence of tissue depletion of vitamin B6, although all the women had abnormal tryptophan metabolism, including increased urinary xanthurenic acid (X.A.) excretion. In the women with vitamin B6 deficiency, administration of this vitamin caused elevation of fasting blood-pyruvate levels, and reduction in plasma glucose, insulin, and blood-pyruvate responses after an oral glucose load. These changes in carbohydrate metabolism were not found in the 28 non-vitamin-B6-deficient women. These results indicate that carbohydrate intolerance in women on O.C. is unlikely to be mediated by the formation of a complex of X.A. with insulin, as has formerly been proposed. Since the synthesis of the tryptophan metabolite quinolinic acid, an inhibitor of the heptaic enzyme phosphoenolpyruvate carboxykinase, may be enhanced by the administration of pyridoxine, it is suggested that this metabolite might be the important factor in the improvement of glucose tolerance in the vitamin-B6-deficient women. This conclusion is supported by the improvement in glucose tolerance observed in 6 women on O.C. and in 4 patients with glucocorticoid excess who were not vitamin-B6 deficient, when they were given tryptophan to augment the synthesis of quinolinic acid.

Adult↗
PubMed1984

The effects of cyproterone acetate and ethinyl oestradiol on carbohydrate metabolism.

Carbohydrate metabolism was studied in a group of 66 women, taking cyproterone acetate (CA) and ethinyloestradiol (EO) as anti-androgen therapy for the treatment of hirsutism and/or acne. A reverse sequential treatment cycle was used and women were studied in two groups: the first when taking the combination of CA and EO during the first 12 days of the treatment cycle, and the second taking EO alone during days 13 to 22. The combination reduced fasting plasma glucose and raised fasting plasma insulin concentrations. There was deterioration of glucose tolerance with increased plasma insulin concentrations and these effects were progressive with time. The plasma insulin response to intravenous tolbutamide was increased by 50% but there was no accompanying change in the glucose nadir as compared with controls. These results show that the combination of CA and EO causes insulin resistance. Plasma C-peptide concentrations following oral glucose were unchanged compared with controls. This shows that the observed hyperinsulinaemia was due to a reduction of hepatic uptake of insulin rather than its increased secretion. We propose that these effects are due to a CA-induced elevation of fasting plasma insulin resulting in downregulation of hepatic insulin receptors with subsequent induction of insulin resistance and impairment of hepatic insulin uptake. C-peptide concentrations following i.v. tolbutamide were significantly higher on treatment with CA and EO than in controls indicating increased pancreatic secretion of insulin. Tests carried out while patients were taking EO alone showed impairment of glucose tolerance only with no change in insulin levels. There was an increase in plasma insulin in response to tolbutamide but this was not significant. We conclude that these results are explained by a reduced but persisting effect of CA.

Acne Vulgaris↗
PubMed2005

Phase I and II metabolism and carbohydrate metabolism in cultured cryopreserved porcine hepatocytes.

Primary porcine hepatocytes were cryopreserved using freezing boxes or a programmable freezer (PF). Upon thawing and culturing in 12-well plates cryopreserved hepatocytes were compared with their fresh controls on days 1 and 2 after plating. Cryopreserved hepatocytes attached approximately as well as fresh hepatocytes and useful cultures were obtained. In cryopreserved hepatocytes, coumarin 7-hydroxylation, 6beta-testosterone hydroxylation and p-nitrophenol glucuronidation were reduced to about 10-40, 35 and 40%, respectively, compared to their fresh counterparts. Glycogen synthesis in cryopreserved hepatocytes was reduced to about 30% on day 1 of culture and about 47% on day 2 of culture compared to the synthesis in fresh hepatocytes. Both fresh and cryopreserved hepatocytes increased the synthesis by twofold in response to stimulation with insulin. Reduced basal levels of glycogen and of glycogen synthesis could be explained by an increased energy demand in cryopreserved hepatocytes needing to repair damages caused by cryopreservation. Glycogenolysis was reduced to about 50% in cryopreserved hepatocytes and gluconeogenesis to about 40% of the glucose production in fresh hepatocytes. In both fresh and cryopreserved hepatocytes the glucose production from glycogenolysis and gluconeogenesis, respectively, was increased fourfold in response to stimulation with glucagon. Overall, the hepatocytes cryopreserved in boxes had a tendency to perform better than hepatocytes cryopreserved in a programmable freezer. In conclusion, the cryopreserved hepatocytes were metabolic active; however, to a lower extent than the fresh hepatocytes, although, the cryopreserved hepatocytes responded as well as the fresh hepatocytes to insulin and glucagon.

Animals↗