Ontogeny of growth hormone releasing hormone and insulin-like growth factors-i and-ii messenger rna in rat placenta

ABSTRACT ABSTRACT: Hypothalamic growth hormone releasing hormone (GHRH) stimulates pituitary growth hormone secretion, which is essential for normal postnatal growth. Reports of an

immunoreactive and biologically active GHRH-like peptide in placenta led us to investigate placenta) expression of GHRH mRNA. Placentas from d 19 gestation fetal rats were assayed for

GHRH-like peptide by ELISA and for GHRH mRNA. Placenta GHRH-like peptide levels averaged 3.7 ± 0.2 ng/g tissue. Dot-blot hybridization revealed the presence of GHRH mRNA in rat placenta in

quantities greater than those of the message in rat hypothalamus. Northern gel analysis of poly-A enriched RNA was used to evaluate the specificity of GHRH mRNA hybridization and to

determine the size of the placental mRNA. Placental and hypothalamic GHRH mRNA were of nearly identical size, although placental RNA had a broad band of hybridization that extended below

that seen in hypothalamus. Further confirmation of homology between placental and hypothalamic GHRH mRNA was determined by an RNAse protection assay, in which a placental protected fragment

was identical in size to that resulting from protection of the hypothalamic complementary RNA. The ontogeny of GHRH mRNA in rat placenta was determined by dot-blot hybridization. The message

was detected at the earliest date examined, d 7, and increased more than 2-fold by d 14 and 5-fold by d 17. The ontogeny of IGF-I and IGF-II mRNA in placenta was also determined. IGF-1 mRNA

was detected at all gestational dates examined, but was highest on d 10, whereas IGF-II mRNA was not detectable on d 7 or 10 but was present on d 14, 17, and 20. We conclude that GHRH mRNA

is present in rat placenta at least from d 7 of gestation. Placental expression of GHRH mRNA is concurrent with maximal expression of placental IGF-II, but not IGF-I mRNA. The similar time

course of expression for GHRH mRNA and IGF-II leads us to speculate that they may have related functions in the last week of rat gestation. SIMILAR CONTENT BEING VIEWED BY OTHERS NESFATIN-1

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Article Open access 26 February 2021 ARTICLE PDF AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Departments of Pediatrics and Physiology and Biophysics, Indiana University Medical Center,

Indianapolis, 46223, Indiana Ora Hirsch Pescovitz & Nancy B Johnson * Department of Pediatrics, University of Minnesota, Minneapolis, 55455, Minnesota Susan A Berry Authors * Ora Hirsch

Pescovitz View author publications You can also search for this author inPubMed Google Scholar * Nancy B Johnson View author publications You can also search for this author inPubMed Google

Scholar * Susan A Berry View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS

ARTICLE Pescovitz, O., Johnson, N. & Berry, S. Ontogeny of Growth Hormone Releasing Hormone and Insulin-Like Growth Factors-I and-II Messenger RNA in Rat Placenta. _Pediatr Res_ 29,

510–516 (1991). https://doi.org/10.1203/00006450-199105010-00019 Download citation * Received: 01 June 1990 * Accepted: 20 December 1990 * Issue Date: 01 May 1991 * DOI:

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