title: Acute effects of thyroid hormones on the production of adrenal cAMP and corticosterone in male rats.
abstract: The acute effects of thyroid hormones on glucocorticoid secretion were studied. Venous blood samples were collected from male rats after they received intravenous 3,5,3'-triiodothyronine (T3) or thyroxine (T4). Zona fasciculata-reticularis (ZFR) cells were treated with adrenocorticotropic hormone (ACTH), T3, T4, ACTH plus T3, or ACTH plus T4 at 37 degrees C for 2 h. Corticosterone concentrations in plasma and cell media, and also adenosine 3',5'-cyclic monophosphate (cAMP) production in ZFR cells in the presence of 3-isobutyl-1-methylxanthine, were determined. The effects of thyroid hormones on the activities of steroidogenic enzymes of ZFR cells were measured by the amounts of intermediate steroidal products separated by thin-layer chromatography. Administration of T3 and T4 suppressed the basal and the ACTH-stimulated levels of plasma corticosterone. In ZFR cells, both thyroid hormones inhibited ACTH-stimulated corticosterone secretion, but the basal corticosterone was inhibited only with T3 > 10(-10) M or T4 > 10(-8) M. Likewise, T3 or T4 at 10(-7) M inhibited the basal- and ACTH-stimulated levels of intracellular cAMP. Physiological doses of T3 and T4 decreased the activities of 3 beta-hydroxysteroid dehydrogenase, 21-hydroxylase, and 11 beta-hydroxylase. These results suggest that thyroid hormones counteract ACTH in adrenal steroidogenesis through their inhibition of cAMP production in ZFR cells.
authors.affiliation: Department of Physiology, National Yang-Ming University, Taipei, Taiwan, Republic of China.
authors.forename: M J
authors.initials: MJ
authors.lastname: Lo
authors.forename: M M
authors.initials: MM
authors.lastname: Kau
authors.forename: Y H
authors.initials: YH
authors.lastname: Chen
authors.forename: S C
authors.initials: SC
authors.lastname: Tsai
authors.forename: Y C
authors.initials: YC
authors.lastname: Chiao
authors.forename: J J
authors.initials: JJ
authors.lastname: Chen
authors.forename: C
authors.initials: C
authors.lastname: Liaw
authors.forename: C C
authors.initials: CC
authors.lastname: Lu
authors.forename: B P
authors.initials: BP
authors.lastname: Lee
authors.forename: S C
authors.initials: SC
authors.lastname: Chen
authors.forename: V S
authors.initials: VS
authors.lastname: Fang
authors.forename: L T
authors.initials: LT
authors.lastname: Ho
authors.forename: P S
authors.initials: PS
authors.lastname: Wang
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D003345:Corticosterone / Q000096:biosynthesis* / Q000097:blood / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis*; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013252:Steroid 11-beta-Hydroxylase / Q000378:metabolism; D013255:Steroid 21-Hydroxylase / Q000378:metabolism; D013963:Thyroid Hormones / Q000494:pharmacology / Q000502:physiology*; D013974:Thyroxine / Q000097:blood / Q000494:pharmacology / Q000502:physiology; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology / Q000502:physiology
chemical_list: D010726:Phosphodiesterase Inhibitors; D013963:Thyroid Hormones; D014284:Triiodothyronine; D005576:Colforsin; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D015096:3-Hydroxysteroid Dehydrogenases; D013255:Steroid 21-Hydroxylase; D013252:Steroid 11-beta-Hydroxylase; D013974:Thyroxine; D015056:1-Methyl-3-isobutylxanthine; D003345:Corticosterone