Fetal and adult sheep adrenal cortical cells contain glucocorticoid receptors.
Specific receptors for glucocorticoids were identified in the fetal and adult sheep adrenal cortex by a whole-cell binding assay using [3H]triamcinolone acetonide ([3H]TA) as the radiolabelled ligand. [3H]TA binding sites were saturable and of high affinity, with dissociation constant (Kd) of 2-3nM. Scatchard analysis revealed a single class of binding sites with a binding capacity (Bmax) of 207 and 5 fmol/10(6) cells for d100 fetuses and adults, respectively. By single point analyses at saturating [3H]TA concentration, we found that glucocorticoid receptors (GR) were present in the fetal adrenal cortex as early as d60. Highest concentrations were found at d100-110. GR decreased to d125, then increased to term (approx. d145) before declining again in newborn and adult animals. This demonstration of glucocorticoid receptors in ovine fetal adrenal cortical cells provides a mechanistic basis for the concept that glucocorticoids may act, perhaps in a paracrine or autocrine fashion, to influence adrenocorticotropin (ACTH)-induced activation of fetal adrenal function and the events leading to parturition.
Yang
K
K
Lawson Research Institute, St. Joseph's Health Centre, Department of Obstetrics and Gynecology, London, Ontario, Canada.
Challis
J R
JR
D000302:Adrenal Cortex / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000375:Aging / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D005260:Female; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D012756:Sheep; D014222:Triamcinolone Acetonide / Q000378:metabolism
D011965:Receptors, Glucocorticoid; D000324:Adrenocorticotropic Hormone; D014222:Triamcinolone Acetonide