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Titolo:
Effect of gestational age and hypoxia on activity of ribonucleic acid polymerase in fetal guinea pig brain
Autore:
Graham, EM; Kubin, JA; Zubrow, A; Mishra, OP; Delivoria-Papadopoulos, M;
Indirizzi:
Johns Hopkins Univ, Sch Med, Dept Gynecol & Obstet, Div Maternal Fetal Med, Baltimore, MD 21218 USA Johns Hopkins Univ Baltimore MD USA 21218 al Med, Baltimore, MD 21218 USA Med Coll Penn & Hahnemann Univ, Sch Med, Dept Pediat, Div Neonatol, Philadelphia, PA 19102 USA Med Coll Penn & Hahnemann Univ Philadelphia PA USA 19102 ia, PA 19102 USA
Titolo Testata:
AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY
fascicolo: 4, volume: 184, anno: 2001,
pagine: 736 - 742
SICI:
0002-9378(200103)184:4<736:EOGAAH>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
CELL-DEATH; RNA; BCL-2; RATS; EXPRESSION; INDUCTION; ISCHEMIA; NUCLEAR; STRESS; BAX;
Keywords:
ribonucleic acid polymerase; fetal guinea pig brain; hypoxia;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
25
Recensione:
Indirizzi per estratti:
Indirizzo: Graham, EM Johns Hopkins Hosp, Dept Gynecol & Obstet, Phipps 228,600 N Wolfe St, Baltimore, MD 21287 USA Johns Hopkins Hosp Phipps 228,600 N Wolfe StBaltimore MD USA 21287
Citazione:
E.M. Graham et al., "Effect of gestational age and hypoxia on activity of ribonucleic acid polymerase in fetal guinea pig brain", AM J OBST G, 184(4), 2001, pp. 736-742

Abstract

OBJECTIVE: The aim of this study was to determine the effect of gestational age and hypoxia on the activity of ribonucleic acid polymerase in fetal guinea pig brain. STUDY DESIGN: Fetal cerebral cortical neuronal nuclei were isolated at 40,50, and 60 days (term) of gestation to determine the effect of gestationalage on the activity of ribonucleic acid polymerase I, II, and III. Pregnant guinea pigs at 60 days' gestation were randomly assigned to a normoxic orhypoxic group to determine the effect of hypoxia on ribonucleic acid polymerase activity. The fetal neuronal nuclei were pooled from 6 pregnant animals in each group. In the normoxic group the pregnant guinea pigs were exposed to room air before delivery. In the hypoxic group delivery occurred after the pregnant guinea pig had been exposed to 7% oxygen for 60 minutes. Thefetuses were delivered by cesarean, and the fetal cerebral cortical neuronal nuclei were isolated immediately. Ribonucleic acid polymerase activity was determined with nuclei suspended in a buffer containing adenosine triphosphate, guanosine triphosphate, cytidine triphosphate, and tritiated uridine triphosphate. Dactinomycin (actinomycin D) and polydeoxyadenylic-thymidylic acid were used to determine the activity of bound and free ribonucleic acid polymerase. a-Amanitin was used to determine the activity of ribonucleic acid polymerase II. RESULTS: The activity of total (bound and free) ribonucleic acid polymerase I and III increased from 85.4 +/- 9.4 fmol of tritiated uridine triphosphate incorporated per milligram of protein per hour at 40 days' gestation to233.3 +/- 82.1 fmol at 50 days and to 343.4 +/- 231.6 fmol at 60 days (P =.02). Total ribonucleic acid polymerase II activity increased from 19.9 +/- 6.0 fmol of tritiated uridine triphosphate incorporated per milligram of protein per hour at 40 days to 123.8 +/- 53.0 fmol at 50 days and to 200.9 /- 77.8 fmol at 60 days (P < .01). In the term fetal guinea pig brain the activity of bound ribonucleic acid polymerase I and III decreased from 116.8 <plus/minus> 107.2 fmol of tritiated uridine triphosphate incorporated per milligram of protein per hour under normoxic conditions to 92.8 +/- 76.0 fmol in hypoxic fetal brain, a decrease of 20.5%. Free ribonucleic acid polymerase I and III activity decreased from 199.2 +/- 115.2 fmol of tritiateduridine triphosphate incorporated per milligram of protein per hour in normoxic fetal brain to 132.0 +/- 66.4 fmol in hypoxic fetal brain, a decreaseof 33.8%. Free ribonucleic acid polymerase II activity decreased from 62.4+/- 70.4 fmol of tritiated uridine triphosphate incorporated per milligramof protein per hour in normoxic fetuses to 13.6 +/- 9.6 fmol in hypoxic fetal brain, a decrease of 78.2%. In contrast, however, in term fetal guinea pig brain, bound ribonucleic acid polymerase II activity increased from 8.0+/- 10.4 fmol of tritiated uridine triphosphate incorporated per milligramof protein per hour under normoxic conditions to 35.2 +/- 8.8 fmol in hypoxic fetal brain, an increase of 340% (P < .01). CONCLUSION: The activity of ribonucleic acid polymerases I, II, and III increases throughout the latter half of gestation, from 40 to 60 days, in thefetal guinea pig brain. Hypoxia in utero is associated with a decrease in ribonucleic acid polymerase I and III activity. Although hypoxia is associated with a decrease in free ribonucleic acid polymerase II activity, we observed a marked increase in bound ribonucleic acid polymerase II activity. which may represent a hypoxia-induced alteration of gene expression.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 14:30:21