Abstract
Objective: To examine the secretory effect of prostaglandin E 2 (PGE 2) and ACTH on the adrenal glands of prenatal and postnatal sheep. Methods: Immunocytochemistry was used to examine the adrenal cortex and medulla for 17α-hydroxylase and tyrosine hydroxylase immunoreactivity. Microphysiometric technique was used to measure [H +] after exposure of whole dispersed prenatal and postnatal adrenal glands to PGE 2, ACTH, or both. Results: Immunocytochemistry showed many cortical-type cells in all adrenal medullae and many medullary-type cells in fetal adrenal cortices. Maximum H + responsiveness to PGE 2 decreased with increasing age. The developmental age-related pattern of maximum percentage change in [H +] during ACTH exposure was similar to previous findings with cortisol production as the endpoint. ACTH stimulated H + production at 80 days' gestation and at all ages greater than 125 days' gestation (P < .05). The molar concentration of ligand required to elicit a response that was 50% of maximum response (EC 50) for the ACTH response was lower in fetuses than in newborn lambs (<1 day and 3 days old), but there was no change in EC 50 for PGE 2 across the ages studied. Adrenal cell response to ACTH after prior ACTH and PGE 2 exposure was higher (P < .05) compared with ACTH after ACTH or ACTH alone at 110 days' gestation only and was lower in 3-day-old lambs. Conclusions: Based on the ACTH results, microphysiometry was a valid method for investigating dispersed adrenal cell physiology. Prostaglandin E 2 stimulated dispersed adrenal cells during the mid-gestation ACTH refractory period, but this effect decreased with increasing age. Prostaglandin E 2 sensitized adrenal cells to ACTH at 110 days' gestation but inhibited ACTH effects at postnatal day 3.
Original language | English (US) |
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Pages (from-to) | 149-157 |
Number of pages | 9 |
Journal | Journal of the Society for Gynecologic Investigation |
Volume | 8 |
Issue number | 3 |
DOIs | |
State | Published - 2001 |
Externally published | Yes |
Keywords
- ACTH
- Fetal sheep
- H production
- In vitro
- Microphysiometer
- Pregnancy
ASJC Scopus subject areas
- Obstetrics and Gynecology