PMID- 11241179 OWN - NLM STAT- MEDLINE DCOM- 20010419 LR - 20190709 IS - 0022-0795 (Print) IS - 0022-0795 (Linking) VI - 168 IP - 3 DP - 2001 Mar TI - The role of the pituitary gland and ACTH in the regulation of mRNAs encoding proteins essential for adrenal steroidogenesis in the late-gestation ovine fetus. PG - 475-85 AB - To further understand the relative roles of the pituitary gland and ACTH in the regulation of mRNAs encoding proteins that are essential for adrenal development, we investigated the effects of, first, an ACTH infusion and labour in intact fetuses and, secondly, the effect of an ACTH infusion to fetuses with and without a pituitary gland, on the relative abundance of the mRNA encoding for the ACTH receptor (MC2R), steroidogenic factor 1 (SF-1), cholesterol side-chain cleavage enzyme (P450(scc)), 3beta-hydroxysteroid dehydrogenase (3betaHSD) and 17alpha-hydroxylase (P450(C17)) in the fetal adrenal gland. ACTH(1-24) infusion (14.7 pmol/kg per h) to intact fetuses was without effect on the abundance of mRNA encoding MC2R and SF-1, irrespective of whether the infusion was given for 18 (115-132 days of gestation) or 32 days (115 days to term (147 days of gestation)). Hypophysectomy (HX) did not alter the expression of MC2R mRNA; however, the abundance of SF-1 mRNA fell by approximately 50% following the removal of the pituitary gland. ACTH(1-24) infusion to HX fetuses failed to restore levels of SF-1 mRNA to that seen in intact animals. P450(scc) and 3betaHSD mRNAs were increased by ACTH(1-24) infusion for 18 days in intact animals, although no effects of the infusion were seen on P450(C17) mRNA levels. For all three of these mRNAs, there was a significant increase in their abundance between 132 days of gestation and term in intact fetuses. By term, ACTH(1-24) infusion was without any additional effect on their abundance. HX decreased the expression of P450(scc), 3betaHSD and P450(C17) mRNAs, while ACTH(1-24) infusion to HX fetuses increased the expression of these mRNAs to levels seen in intact animals. There were significant correlations between the abundance of the mRNA for P450(scc), 3betaHSD and P450(C17), but not MC2R and SF-1, and premortem plasma cortisol concentrations. These results emphasise the importance of the pituitary gland and ACTH in the regulation of the enzymes involved in adrenal steroidogenesis. Factors in addition to ACTH may also play some role, as the infusion was not always effective in increasing the abundance of the mRNAs. Surprisingly, the mRNA for MC2R and SF-1 did not appear to be regulated by ACTH in the late-gestation ovine fetus, though a pituitary-dependent factor may be involved in the regulation of SF-1 mRNA abundance. FAU - Simmonds, P J AU - Simmonds PJ AD - Department of Physiology, Monash University, PO Box 13F, Clayton, Victoria 3800, Australia. FAU - Phillips, I D AU - Phillips ID FAU - Poore, K R AU - Poore KR FAU - Coghill, I D AU - Coghill ID FAU - Young, I R AU - Young IR FAU - Canny, B J AU - Canny BJ LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - England TA - J Endocrinol JT - The Journal of endocrinology JID - 0375363 RN - 0 (Enzymes) RN - 0 (RNA, Messenger) RN - 9002-60-2 (Adrenocorticotropic Hormone) RN - WI4X0X7BPJ (Hydrocortisone) SB - IM MH - Adrenal Glands/*embryology/enzymology/physiology MH - Adrenocorticotropic Hormone/pharmacology/*physiology MH - Animals MH - Embryonic and Fetal Development/physiology MH - Enzymes/genetics MH - Female MH - Gene Expression Regulation, Developmental/drug effects/*physiology MH - Hydrocortisone/blood MH - Labor, Obstetric/physiology MH - Pituitary Gland/*physiology MH - Pregnancy MH - RNA, Messenger/genetics MH - Sheep/*embryology/physiology EDAT- 2001/03/10 10:00 MHDA- 2001/04/21 10:01 CRDT- 2001/03/10 10:00 PHST- 2001/03/10 10:00 [pubmed] PHST- 2001/04/21 10:01 [medline] PHST- 2001/03/10 10:00 [entrez] AID - JOE04006 [pii] AID - 10.1677/joe.0.1680475 [doi] PST - ppublish SO - J Endocrinol. 2001 Mar;168(3):475-85. doi: 10.1677/joe.0.1680475.