title: Developmental expression of the growth hormone receptor gene in the rat hypothalamus.
abstract: The ontogeny of growth hormone receptor (GHR) gene expression was studied in the rat hypothalamus. Total RNA from the hypothalamus of rats at different developmental stages (embryonic day 15-56 days of age) was characterized using a 32P-labeled RNA probe derived from the extracellular domain of the rat GHR cDNA. Two RNA species, 4.5 kilobases (kb) encoding for GHR and 1.2 kb encoding for GH-binding protein, were detected in hypothalamic tissue from embryonic day 15 to 56 days of age. Their levels were low at embryonic day 15 and increased toward 3 days of age. The level of 4.5-kb transcript preferentially increased from 7 days after birth, and it was maintained until 35 days of age. Thereafter, the level of 4.5-kb transcript declined. The ratio between the 4.5- and 1.2-kb transcripts was less than 2.0 from embryonic day 15 to 3 days after birth, while it was larger than 4 after 7 days of age. There was no sex difference in the levels or the ratios of the transcripts of the GHR gene from 7 to 56 days of age. The findings indicate that the 4.5-kb transcript preferentially processed postnatally in the rat hypothalamus.
authors.affiliation: Department of Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Hasegawa
authors.forename: S
authors.initials: S
authors.lastname: Minami
authors.forename: H
authors.initials: H
authors.lastname: Sugihara
authors.forename: I
authors.initials: I
authors.lastname: Wakabayashi
mesh_terms: D000818:Animals; D016375:Antisense Elements (Genetics); D015152:Blotting, Northern; D018076:DNA, Complementary / Q000378:metabolism; D003720:Densitometry; D005260:Female; D007031:Hypothalamus / Q000254:growth & development* / Q000378:metabolism; D010957:Plasmids; D011247:Pregnancy; D015347:RNA Probes; D051381:Rats; D017208:Rats, Wistar; D011986:Receptors, Somatotropin / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D016375:Antisense Elements (Genetics); D018076:DNA, Complementary; D015347:RNA Probes; D011986:Receptors, Somatotropin