title: Effects of vitamin D3 metabolites on thyrotropin secretion from rat pituitary cells in culture.
abstract: The effects of several vitamin D3 metabolites on TSH secretion were investigated using rat pituitary cells in culture. After a 24-h incubation in Dulbecco's medium, only 25,26-dihydroxyvitamin D3 [25,26(OH)2D3] at 10(-6) M increased the basal TSH secretion (36% above control). The TRH-induced TSH secretion increased dose-dependently with increasing concentrations of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] showing a significant increase at 10(-8) M (41% above control). At 10(-5) M 25,26(OH)2D3 the TRH-stimulated TSH secretion was also increased (63% above control). In medium containing charcoal-treated serum, 1, 24,25-trihydroxyvitamin D3 [1,24,25(OH)3D3] decreased the TRH-induced TSH secretion dose dependently (34% below control at 10(-8) M), while the effects of both 1,25(OH)2D3 and 25,26(OH)2D3 were blunted. Our results indicate that several vitamin D3 metabolites may affect pituitary TSH secretion.
authors.affiliation: Endocrine Research Laboratory, University of Helsinki, Minerva Foundation Institute for Medical Research, Helsinki, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Törnquist
authors.forename: L
authors.initials: L
authors.lastname: Forss
authors.forename: C
authors.initials: C
authors.lastname: Lamberg-Allardt
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3 / Q000494:pharmacology*; D000818:Animals; D002112:Calcifediol / Q000494:pharmacology*; D002117:Calcitriol / Q000494:pharmacology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D006887:Hydroxycholecalciferols / Q000494:pharmacology*; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013972:Thyrotropin / Q000378:metabolism*; D014807:Vitamin D / Q000378:metabolism
chemical_list: D006887:Hydroxycholecalciferols; D014807:Vitamin D; D015650:24,25-Dihydroxyvitamin D 3; C013721:1,24,25-trihydroxyvitamin D3; D013972:Thyrotropin; D002117:Calcitriol; D002112:Calcifediol