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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adrenal growth occurs in experimental diabetes, and evidence exists for increased adrenal function. The concentration of PPRibP has been examined in the rat adrenal gland at various times after induction of diabetes with STZ, in view of the key role it plays in the synthesis of Purs and Pyrs. The PPRibP level was exceptionally high in the adrenal gland and increased faster than the rate of growth during the initial rapid growth phase--the first 7 days after STZ was given; PPRibP synthetase showed a parallel increase. Formation of R5P via the oxidative and nonoxidative segments of the PPP also was measured. The oxidative enzymes, G-6-PD and 6-PGD, increased in parallel with growth during the early phase, but showed a more marked rise during the secondary, slower, growth phase seen 6 wk after STZ was given, when this may be associated with the known sustained rise in plasma corticosteroids. The nonoxidative enzymes of the PPP, an alternate route for the production of R5P, showed smaller changes. The specifically high adrenal concentration of PPRibP may be related to the high Km for PPRibP (250 microM) of the first enzyme of the de novo pathway of Pur synthesis, as such synthesis may be required in the rat to replace the net loss of ATP associated with catecholamine secretion. Factors controlling PPRibP synthetase and their potential relative importance in the adrenal gland have been considered.
Diabetes 1992 Nov
PMID:Phosphoribosyl pyrophosphate formation in the rat adrenal gland in relation to adrenal growth in experimental diabetes. 138 69

The effect of developmental growth on the kidney content of phosphoribosyl pyrophosphate PPRibP was studied in rats at ages between the foetal animal and up to 100 days of age. In addition, the effect of short-term diabetes (up to 14 days) on the renal content of PPRibP was studied in immature rats and in adults aged approx. 60 days. The developmental pattern of PPRibP is such that the PPRibP content is lowest in the young rat and increases as the rate of kidney growth slows. In the adult rat, the early kidney hypertrophy of diabetes is accompanied by a fall in PPRibP content and, again, the PPRibP content returns to normal as the rate of kidney hypertrophy diminishes. Induction of diabetes in the immature rat causes a lesser degree of kidney hypertrophy and also a smaller depression of renal PPRibP content. The activity of PPRibP synthetase (EC 2.7.6.1) is not significantly affected by age or diabetes. The changes in PPRibP content are discussed in relation to the generation of ribose 5-phosphate by the pentose phosphate pathway and the utilization of PPRibP for nucleotide synthesis via the 'de novo' and salvage pathways.
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PMID:Concentration of phosphoribosyl pyrophosphate in the kidney during development and in experimental diabetic hypertrophy. 242 32

Changes in the tissue content of phosphoribosyl pyrophosphate (PPRibP), glucose 6-phosphate, ribose 5-phosphate (Rib5P), RNA and DNA, of the activity of PPRibP synthetase (EC 2.7.6.1) and the conversion of [1-14C]- and [6-14C]-glucose into 14CO2 were measured at mid-lactation in the normal and diabetic rat and in pregnancy, lactation and mammary involution in the normal rat. The PPRibP, glucose 6-phosphate and Rib5P contents increase during pregnancy and early lactation to reach a plateau value at mid-lactation, before falling sharply during weaning. The PPRibP content, PPRibP synthetase activity and flux of glucose through the oxidative pentose phosphate pathway (PPP) all change in parallel during the lactation cycle. Similarly, after 3 and 5 days duration of streptozotocin-induced diabetes, ending on day 10 of lactation, there were parallel declines in PPRibP content, PPRibP synthetase and PPP activity. The effect of streptozotocin was prevented by pretreatment with nicotinamide and partially reversed by insulin administration. Addition of insulin to lactating rat mammary-gland slices incubated in vitro significantly raised the PPRibP content (+47%) and the activity of the PPP (+40%); phenazine methosulphate, which gives a 2-fold increase in PPP activity, raised the PPRibP content of lactating mammary gland slices by approx. 3-fold. It is concluded that Rib5P, generated in the oxidative segment of the PPP, is an important determinant of PPRibP synthesis in the lactating rat mammary gland and that insulin plays a central role in the regulation of the bioavailability of this precursor of nucleotide and nucleic acid synthesis.
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PMID:Phosphoribosyl pyrophosphate and phosphoribosyl pyrophosphate synthetase in rat mammary gland. Changes in the lactation cycle and effects of diabetes, insulin and phenazine methosulphate. 243 83

Studies were made of the renal phosphoribosyl pyrophosphate (PPRibP) content and PPRibP synthetase (EC 2.7.6.1) activity in rats diabetic for 5, 14 or 20 days, or unilaterally nephrectomized (UN) for 5 days, and in doubly lesioned animals. Approximately equal degrees of renal enlargement were found after 5 days diabetes or 5 days UN. In the doubly lesioned animals the increment of growth was additive. Unilateral nephrectomy of 5 days duration, in contrast with diabetes, had no effect on the PPRibP content of the contralateral kidney, nor did it modify the renal PPRibP content when performed on animals diabetic for 5, 14 or 20 days. The activity of PPRibP synthetase was unaffected by diabetes, UN or diabetes +UN. The results pinpoint a stage of nucleotide synthesis which is differentially affected by the two stimuli, in line with evidence for differences in regulation of nucleic acid turnover in the two conditions.
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PMID:Concentration of phosphoribosyl pyrophosphate in renal hypertrophy. Contrasting effects of early diabetes and unilateral nephrectomy. 243 88

Measurements have been made of the tissue content of phosphoribosyl pyrophosphate (PPRibP) and of a range of metabolic intermediates involved in the energy charge of the cell, the glycolytic and pentose phosphate pathways, and of the activity of the enzymes of the pentose phosphate pathway and of PPRibP synthetase (EC 2.7.6.1) in the livers of normal, diabetic, insulin-treated diabetic and starved rats and in livers of rats previously starved and then re-fed with high-fat or high-carbohydrate diets. Diabetes, starvation and high-fat diet all caused a fall in the hepatic PPRibP content, whereas insulin treatment and high-carbohydrate diet raised the tissue content. A positive correlation was shown between the PPRibP content and ATP, energy charge and the cytosolic [NAD+]/[NADH] quotient. A positive association between the PPRibP content and the flux of glucose through the pentose phosphate pathway and the synthesis of ribose 5-phosphate via the oxidative enzymes of that pathway, including ribose-5-phosphate isomerase (EC 5.3.1.6), was also observed. A negative correlation was found between the ADP, AMP and Pi contents, and no correlation existed between PPRibP content and the enzymes of the non-oxidative branch of the pentose phosphate pathway. There was no correlation between hepatic PPRibP content and the activity of PPRibP synthetase measured in vitro. These results are considered in relation to the control of PPRibP synthetase in the liver in vivo.
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PMID:Hepatic phosphoribosyl pyrophosphate concentration. Regulation by the oxidative pentose phosphate pathway and cellular energy status. 244 9