Corticotrophin-releasing factor-like immunoreactivity and bioactivity of human fetal and adult hypothalami

Abstract

Corticotrophin releasing factor-like immunoreactivity (CRF-LI) and bioactivity, and arginine vasopressin-like immunoreactivity (AVP-LI) have been measured in extracts of human fetal and adult hypothalamic tissue and their development with the gestational age of the fetuses (12-27 weeks) studied. CRF-LI was measured by a radioimmunoassay developed for ovine corticotrophin-releasing factor (oCRF-41). Corticotrophin-releasing factor bioactivity was measured in a rat isolated anterior pituitary cell perfusion system. CRF-LI and bioactivity and AVP-LI were all detectable in fetal hypothalamic extracts from 12 to 13 weeks of gestational age. CRF-LI was also present in human fetal pituitary glands from 12 weeks of gestational age. The concentration of CRF-LI in the fetal hypothalamic extracts (9.2 +/- 11.4 ng/g, mean +/- S.E.M., n = 33) showed no significant correlation with the gestational age of the fetuses. However the concentration of AVP-LI (25.0-36.8 ng/g, n = 17) did show a positive correlation (r = 0.508, P less than 0.05) with gestational age, as did the concentration of CRF bioactivity (471.3-556.3 ng ACTH released/g tissue, n = 13, r = 0.725, P less than 0.01). The CRF bioactivity of all fetal hypothalamic extracts was potentiated by the addition of synthetic human (h)AVP, but the bioactivity of the adult hypothalamic extracts was not, presumably because of the higher levels of AVP-LI already present in the adult extracts. Pretreatment of tissue extracts with antisera to oCRF-41 and/or hAVP reduced the CRF bioactivity of all hypothalamic extracts. Sephadex chromatography of fractions which co-eluted with synthetic oCRF-41 or hAVP contained CRF bioactivity and this bioactivity was potentiated when synthetic hAVP or oCRF-41, respectively, were added to the fractions. However, a larger molecular weight form of CRF-LI (8000-10 000 daltons), which was observed only in fetuses of 20 weeks of gestational age or less, did not contain any significant CRF bioactivity.

A Transcriptome-Wide Screen for mRNAs Enriched in Fetal Leydig Cells: CRHR1 Agonism Stimulates Rat and Mouse Fetal Testis Steroidogenesis

“…Ucn1 mRNA was undetectable in all organs screened, but Crh mRNA levels were detectable in brain and hypothalamus. This is consistent with ISH data from other labs showing Crh mRNA is present in the hypothalamus of fetal rats beginning around GD17 to GD21 [51], [52], and Crh expression is seen in the human fetal hypothalamus as early as GW12 [53]. At all gestation ages examined, no Crh or Ucn1 mRNA was observed in the fetal testis.…”

Corticotropin-Releasing Factor-Like Immunoreactivity, Arginine Vasopressin-Like Immunoreactivity and ACTH-Releasing Bioactivity in Hypothalamic Tissue from Fetal and Neonatal Sheep

“…The concentrations of both CRF-LI and AVP-LI measured in ovine fetal hypothalamic extracts are similar to those observed in human fetuses between 12 and 28 weeks of gestation [1). Moreover, these findings appear in good agreement with a previous report by Levidiotis et al [10] showing that AVP could be detected earlier than CRF in the fetal sheep median eminence by immunocytochemical methods.…”

Mechanisms of Norepinephrine Mediated Corticotropin-Releasing Factor-41 Release from Cultured Fetal Hypothalamic Cells

“…180 ,ul of samples were used for the assay and 20 pi 500 m A7 phosphate buffer was added to maintain the same concentration of phosphate buffer as standard. Specific antiserum [31 ] was used at a final dilution of 1:48,000. Tyr-CRF-41 iodinated with l25I using the chloramine-T method was used for the assay.…”