Linked Life Data

2982590

Source:http://linkedlifedata.com/resource/pubmed/id/2982590

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1985-4-25
pubmed:abstractText
Although it is known that LH secretion starts at 17 days of gestation in the fetal rat and that this first LH release is most likely driven by hypothalamic GnRH, an earlier role for GnRH during fetal life has been postulated with the observation that presence of GnRH is important before day 13 of gestation for the differentiation of the pituitary anlage. In order to clarify the different roles of GnRH during fetal life, we have studied the first appearance of GnRH in the fetal brain, the expression of GnRH receptors in the fetal pituitary gland, and the presence of GnRH immunoreactivity within the fetal gonadotrophs. GnRH was present in the earliest brain tissue examined (12 days of gestation). From 12-17 days, GnRH content of fetal brain remained low and then increased markedly by the end of gestation. No immunoreactive GnRH-like material could be detected in rat placental tissue throughout gestation. Binding sites for GnRH were detected as early as 12 days of gestation in fetal pituitary glands. However, binding was very low until 16 days. At 17 days, Scatchard analysis indicated the presence of high affinity, low capacity binding sites [affinity constant (Ka) = 10(10) M-1]. Intracellular presence of GnRH as seen by immunocytochemistry using ultrathin sections prepared by cryoultramicrotomy was first visible at 14 days and started to increase at 16 days. LH was first detectable in the fetal pituitary by RIA at 17 days; FSH was first detectable at 21 days, and PRL at 1 day of postnatal life. Thereafter, neonatal pituitary contents of LH, FSH, and PRL increased linearly with-time, as did the number of pituitary GnRH receptors. At 10 days of postnatal life, pituitary contents of LH and FSH were significantly higher in females than in males. In summary, hypothalamic GnRH appears early in fetal life and potentially can induce differentiation of the pituitary anlage. Conversely, the presence at 15 days of gestation of specific binding sites for GnRH and of intracellular GnRH immunoreactivity in gonadotrophs indicates that the hypophysiotropic action of GnRH clearly precedes the start of LH biosynthesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
116
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1565-76
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Ontogeny of hypothalamic luteinizing hormone-releasing hormone (GnRH) and pituitary GnRH receptors in fetal and neonatal rats.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't