Calcitonin inhibits Na/sup +/ gradient-dependent phosphate uptake across renal brush-border membranes

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:5765428

Yusufi, A N.K.; Berndt, T J; Murayama, N; Knox, F G; Dousa, T P

This study was undertaken to determine whether calcitonin inhibits Na/sup +/-(P/sub i/) cotransport across luminal brush-border membrane (BBM) of proximal tubules. Further, the authors determined the relative inhibitions of inorganic phosphate (P/sub i/) transport in BBM vesicles (BBMV) derived from superficial cortical tissue (BBMV-SC) and juxtamedullary tissue (BBMV-JM). The effects of maximally phosphaturic doses of calcitonin were compared with those of parathyroid hormone (PTH). Experiments were performed in acutely thyroparathyroidectomized (TPTX) rats fed either normal (NPD, 0.7%) P/sub i/ diets. After measurement of the fractional excretion of phosphate (FE/sub P/sub i//) by clearance, the BBMV-SC and BBMV-JM were prepared from kidneys of the same animals and uptakes of /sup 32/P/sub i/ were determined. Both calcitonin and PTH inhibited BBMV transport of P/sub i/ to a greater degree in BBMV-JM than in BBMV-SC, in rats fed NPD or LPD. Kinetic analysis shows that administration of calcitonin resulted in marked decrease of apparent V/sub max/ for P/sub i/ without any changes in apparent K/sub m/ for P/sub i/. They conclude that calcitonin administration decreases the capacity for Na/sup +/-P/sub i/ cotransport across BBM in proximal tubules of the acutely TPTX rat.

• Research Organization: Mayo Clinic Rochester, MN
• OSTI ID: 5765428
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:4; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMINO ACIDS
ANIMALS
AZOLES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BLOOD-PLASMA CLEARANCE
BODY
CALCITONIN
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CLEARANCE
DAYS LIVING RADIOISOTOPES
DIET
EXCRETION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HORMONES
INHIBITION
ISOTOPES
KIDNEYS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
MEDICINE
MEMBRANES
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PARATHORMONE
PEPTIDE HORMONES
PEPTIDES
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
POLYPEPTIDES
PROLINE
PROTEINS
PYRROLES
PYRROLIDINES
RADIOISOTOPES
RATS
RODENTS
SURGERY
UPTAKE
VERTEBRATES