title: Hormonal regulation of sodium/sulfate co-transport in renal epithelial cells.
abstract: Serum sulfate concentrations are elevated in infants, young children, and pregnant women due, at least in part, to increased renal sulfate reabsorption. Little is known about the effects of hormones, particularly those involved in growth, development, and pregnancy, on renal sulfate reabsorption. The objective of this investigation was to examine the effects of growth hormone (GH), insulin-like growth factor 1 (IGF-1), progesterone (PG), and 17beta-estradiol (EST) on renal sodium/sulfate co-transport. 35S-sulfate uptake was determined in Madin-Darby canine kidney (MDCK)/NaSi-1 cells (MDCK cells that have been stably transfected with rat sodium/sulfate co-transporter (NaSi-1) cDNA) and in opossum kidney (OK) cells. NaSi-1 mRNA was determined by RT-PCR and protein levels by ELISA. GH (0.1 nM) significantly increased the sodium/sulfate co-transport in MDCK/NaSi-1 cells up to 35%. IGF-1 induced a concentration-related stimulation of the sodium/sulfate co-transport with a maximal response observed at 1000 nM (59% increase). Sodium-dependent sulfate uptake was significantly increased when cells were preincubated with 10 nM PG, 10 nM EST, or 10 nM PG/10 nM EST up to 41%, 46%, or 39%, respectively. OK cells exhibited endogenous sodium-dependent sulfate transport; significantly increased sodium/sulfate co-transport was also observed in OK cells that were preincubated with GH, IGF-1, and PG/EST, although not with EST alone. The NaSi-1 mRNA and NaSi-1 protein levels were significantly increased in MDCK/NaSi-1 cells treated with 0.1 nM GH, 100 nM IGF-1, 10 nM PG, and/or 10 nM EST compared with control. These results suggest that the increased renal sulfate reabsorption that occurs in neonates, young and pregnant humans, and animals could be mediated by the increased steady-state levels of NaSi-1 mRNA produced by the higher plasma concentrations of GH, IGF-1, or PG/EST.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, State University of New York at Buffalo, Amherst, New York 14260, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Sagawa
authors.forename: W
authors.initials: W
authors.lastname: Shi
authors.forename: H
authors.initials: H
authors.lastname: Murer
authors.forename: M E
authors.initials: ME
authors.lastname: Morris
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins; D002460:Cell Line; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology*; D019382:Human Growth Hormone / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007668:Kidney / Q000378:metabolism*; D008560:Membrane Fluidity / Q000187:drug effects; D009893:Opossums; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012964:Sodium / Q000378:metabolism; D000077003:Sodium Sulfate Cotransporter; D013431:Sulfates / Q000378:metabolism; D027981:Symporters; D014162:Transfection
chemical_list: D002352:Carrier Proteins; D027682:Cation Transport Proteins; D006728:Hormones; D012333:RNA, Messenger; D000077003:Sodium Sulfate Cotransporter; D013431:Sulfates; D027981:Symporters; D019382:Human Growth Hormone; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D012964:Sodium