PMID- 1338959
OWN - NLM
STAT- MEDLINE
DCOM- 19930625
LR  - 20061115
IS  - 0449-3087 (Print)
IS  - 0449-3087 (Linking)
VI  - 45
DP  - 1992
TI  - Regulation of gene expression in the ovine fetus.
PG  - 85-95
AB  - Expression of genes encoding pro-opiomelanocortin (POMC), glucocorticoid 
      receptors and 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) was studied in 
      sheep fetuses during development. POMC mRNA was present in the anterior pituitary 
      by day 60 of gestation (term approximately 145 days), and its relative amount did 
      not change significantly until after days 125-130. The amount of POMC mRNA in the 
      pituitary increased significantly at days 138-143, remained high at term and 
      increased further in newborn lambs. In contrast, POMC mRNA could not be detected 
      in the hypothalamus and adrenal glands of fetuses at all ages studied. These 
      results suggest that the prepartum rise in plasma adrenocorticotrophin (ACTH) 
      concentrations in sheep fetuses is due to increased expression of POMC gene in 
      the pituitary. The number of glucocorticoid receptors, but not the amount of 
      glucocorticoid receptor mRNA changed significantly with gestational age in the 
      hypothalamus, anterior pituitary and adrenal glands of the fetus. Changes in 
      glucocorticoid receptor content of fetal tissues may reflect alterations in 
      translation of glucocorticoid receptor mRNA, subsequent modifications, or 
      glucocorticoid receptor turnover or a combination of these factors. However, in 
      newborn lambs, amounts of glucocorticoid receptor mRNA increased significantly in 
      the hypothalamus and pituitary but decreased to undetectable amounts in the 
      adrenal glands, indicating that tissue-specific factors may influence expression 
      of glucocorticoid receptor gene in neonatal sheep. The interconversion of 
      cortisol and cortisone requires 11 beta-HSD. Since cortisone is biologically 
      inactive, 11 beta-HSD may regulate the activity of intracellular cortisol. We 
      cloned and sequenced a cDNA encoding sheep 11 beta-HSD. By northern blot 
      analysis, this cDNA detected a single 1.8 kb transcript in the fetal and adult 
      sheep liver, lung, hypothalamus, anterior pituitary and placenta. This could not 
      be detected in the adrenal glands and kidneys, but a smaller (1.5 kb) transcript 
      was present in the fetal and adult kidneys. During fetal development, the 
      relative amount of 11 beta-HSD mRNA did not change significantly in the kidney 
      and lung, but increased in lungs from newborn lambs. In contrast, amounts of 
      hepatic 11 beta-HSD mRNA not only increased significantly in the fetus at term 
      but also displayed a further increase in the newborn. These results clearly 
      indicate that expression of ovine 11 beta-HSD gene in the fetus and newborn is 
      regulated in a tissue-specific and developmentally programmed manner.
FAU - Yang, K
AU  - Yang K
AD  - Lawson Research Institute, St Joseph's Hospital, Department of Obstetrics and 
      Gynecology, University of Western Ontario, London, Canada.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Review
PL  - England
TA  - J Reprod Fertil Suppl
JT  - Journal of reproduction and fertility. Supplement
JID - 0225652
RN  - 0 (RNA, Messenger)
RN  - 0 (Receptors, Glucocorticoid)
RN  - 66796-54-1 (Pro-Opiomelanocortin)
RN  - 9002-60-2 (Adrenocorticotropic Hormone)
RN  - EC 1.1.- (Hydroxysteroid Dehydrogenases)
RN  - EC 1.1.1.146 (11-beta-Hydroxysteroid Dehydrogenases)
SB  - IM
MH  - 11-beta-Hydroxysteroid Dehydrogenases
MH  - Adrenocorticotropic Hormone/blood
MH  - Animals
MH  - Embryonic and Fetal Development/*genetics
MH  - *Gene Expression Regulation
MH  - Hydroxysteroid Dehydrogenases/genetics
MH  - Pro-Opiomelanocortin/genetics
MH  - RNA, Messenger/metabolism
MH  - Receptors, Glucocorticoid/genetics
MH  - Sheep/*genetics
RF  - 59
EDAT- 1992/01/01 00:00
MHDA- 1992/01/01 00:01
CRDT- 1992/01/01 00:00
PHST- 1992/01/01 00:00 [pubmed]
PHST- 1992/01/01 00:01 [medline]
PHST- 1992/01/01 00:00 [entrez]
PST - ppublish
SO  - J Reprod Fertil Suppl. 1992;45:85-95.