Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the neonatal rat, the response of the hypothalamo-pituitary-adrenal axis to stressful stimuli is markedly decreased during the first 2 weeks of life. This peculiar period was named "stress hyporesponsive period." In this report, we studied the effect of insulin-induced hypoglycemia, known as a strong stimulator of the corticotroph function in the adult rat. Rats (8- or 20-day-old) were injected ip with 3 IU/kg synthetic insulin and were killed at various times. In 20-day-old rats, hypoglycemia induced a rapid drop in blood glucose concentrations accompanied by a stimulation of ACTH and corticosterone secretion which reached maximal values within 30 min. On the opposite, in 8-day-old rats, despite a rapid decrease in blood glucose levels, insulin injection induced a gradual rise of plasma ACTH and corticosterone concentrations which peaked at 90 min. This delayed response of the hypothalamo-pituitary-adrenal axis to hypoglycemia in the youngest rats does not seem to be due to a difference of sensitivity to insulin-induced hypoglycemia since injection of increasing doses of insulin (0.3, 0.75, or 3 IU/kg body wt) induced a dose-related decrease of blood glucose concentrations and a rise in plasma ACTH and corticosterone levels, comparable in the two age group studied. Basal or hypoglycemia-stimulated absolute corticosterone values were much lower in 8-day-old rats than in 20-day-old animals, suggesting an immaturity of the adrenal glands in the youngest animals. Daily ACTH injection, starting 3 days before the experiment, had a trophic effect on the adrenal glands leading to a more important increase of corticosterone levels after hypoglycemia in 8-day-old rats. Our results confirm that there is an immaturity of the adrenal glands in young rats, probably due to the low plasma ACTH levels during the neonatal period. To determine the respective role of the two major hypothalamic ACTH secretagogues, we studied the effect of passive immunization against CRF or arginine vasopressin (AVP) on plasma ACTH response after hypoglycemia. Passive immunization against AVP decreased significantly hypoglycemia-stimulated ACTH secretion in both 8- and 20-day-old rats, while no change of plasma ACTH response to insulin injection was observed after passive immunization against CRF. This results suggest that CRF does not seem to be involved in the regulation of ACTH secretion after hypoglycemia in the young rat while AVP seems to be the main hypothalamic stimulatory factor for anterior pituitary corticotrophs response to hypoglycemia during the postnatal period.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Stimulation of adrenocorticotropin secretion by insulin-induced hypoglycemia in the developing rat involves arginine vasopressin but not corticotropin-releasing factor. 131 56

Chronic renal failure was diagnosed in 6 young Standard Poodles from 2 related litters. Clinically, the disease was characterized by polydipsia, polyuria, anorexia, lethargy, vomiting, and bony deformities suggestive of fibrous osteodystrophy. Laboratory evaluation revealed azotemia and hypercholesterolemia in all 6 dogs and nonregenerative anemia in 3 dogs. Two dogs had hyperphosphatemia and another 2 were hypercalcemic. Isosthenuria and proteinuria were found in both dogs for which urinalyses were available. The kidneys were characterized pathologically by interstitial fibrosis, variable interstitial infiltrates of lymphocytes and plasma cells, tubular atrophy, tubular dilatation, tubular basement membrane mineralization, cystic glomerular atrophy, and immaturity of glomeruli, with inconspicuous capillary lumens.
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PMID:Juvenile renal disease in related Standard Poodles. 662 80

Myocardial calcification has been rarely described in premature infants after myocardial infarction and myocarditis with coxsackievirus B1. In adults and older children, metastatic myocardial calcification has been reported in chronic renal failure. We report a case of myocardial calcification in a 680-gm preterm infant after a prolonged course of renal failure complicated by secondary hyperparathyroidism. Subclinical myocardial injury was evidenced by a high serum creatine phosphokinase MB band concentration, which probably provided a susceptible substrate for the deposition of calcium crystals, because the multiplication product of serum calcium and inorganic phosphorus levels transiently exceeded 75 mg x mg/100 ml, indicating serum saturation during the course of secondary hyperparathyroidism. We report this case as an unusual complication of renal immaturity in extremely low birth weight infants and an indication of a relatively intact parathyroid glandular function in them. Hypoxia, myocardial dysfunction, and renal failure are common complications in such infants, and in the presence of renal failure, the serum levels of calcium and inorganic phosphorus should be maintained below the pathologic level to avoid ectopic calcification of the tissues, including the myocardium.
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PMID:Myocardial calcification in an extremely low birth weight infant with chronic renal failure and secondary hyperparathyroidism. 851 2