Pituitary 1,25-dihydroxyvitamin D3 receptors in hyperthyroid- and hypothyroid-rats.
The binding of 1 alpha,25-dihydroxy (26,27-methyl-[3H]) cholecalciferol ([3H]1,25-(OH)2D3) to its receptor in cytosol of the anterior pituitary cells was examined in hyperthyroid- and hypothyroid rats, as well as in normal rats. The binding capacity increased by 41% in L-Thyroxine-treated hyperthyroid rats and decreased by 49% in propylthiouracil-ingested hypothyroid rats as compared with normal control rats, whereas the affinity of the receptor for [3H]-1,25(OH)2D3 showed no difference among these 3 animal groups. These findings indicate that the number of 1,25(OH)2D3 receptors in the pituitary may be regulated by thyroid hormone, and further suggest that 1,25-(OH)2D3 may play some role in regulating functions of the anterior pituitary.
D000818:Animals; D002117:Calcitriol / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D003600:Cytosol / Q000378:metabolism; D006980:Hyperthyroidism / Q000139:chemically induced / Q000378:metabolism*; D007037:Hypothyroidism / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D011441:Propylthiouracil; D051381:Rats; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D011441:Propylthiouracil; D013972:Thyrotropin; D002117:Calcitriol; D013974:Thyroxine