title: Effect of gestational age, CRF and cortisol on ACTH secretion from slices of fetal sheep pituitaries in an in vitro perifusion system.
abstract: We have investigated whether increasing gestational age has an effect on basal and K(+)- or CRF-stimulated ACTH secretion from slices of anterior pituitary from fetal sheep. We have also determined whether cortisol acts to inhibit basal or CRF-induced ACTH secretion from the fetal sheep pituitary between 106 and 144 days of gestation (term = 145 +/- 3 days of gestation). Four slices were collected from each fetal sheep pituitary at 106-116 (n = 4 pituitaries), 120-124 (n = 4), 130-137 (n = 8) and 140-144 days (n = 11) and perifused with Krebs buffer bubbled with 95% O2 and 5% CO2 at 37 degrees C. Slices were perifused for at least 120 min prior to one of the following treatments: K+ (100 mM); CRF (two separate boluses, 10 nM, administered 120 min apart); cortisol (100 nM, 30-min infusion), or cortisol (30-min infusion) with a CRF bolus administered 10 min after the start and 90 min after the end of the cortisol infusion. The basal output of ACTH (pg/mg/120 min) did not change significantly between 106 and 144 days of gestation. Bolus administration of K+ or CRF stimulated pituitary ACTH secretion above baseline values for 10 min at all ages.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology, Monash University, Clayton, Australia.
authors.forename: I C
authors.initials: IC
authors.lastname: McMillen
authors.forename: J J
authors.initials: JJ
authors.lastname: Merei
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005260:Female; D005865:Gestational Age; D006854:Hydrocortisone / Q000494:pharmacology*; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D011247:Pregnancy; D012756:Sheep
chemical_list: D007457:Iodine Radioisotopes; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D011188:Potassium; D006854:Hydrocortisone