title: [Effect of Hypericum perforatum extract on in vitro labelling of blood elements with technetium-99m and on biodisponibility of sodium pertechnetate in Wistar rats].
abstract: OBJECTIVE
  To evaluate the effect of a hiperico extract (Hypericum perforatum) on the labeling of blood elements with technetium-99m (99mTc) and in the bioavailability of the radiopharmaceutical sodium pertechnetate in Wistar rats.
  
  
  METHODS
  Blood (heparinized) withdrawn from Wistar rats is incubated with a hiperico extract, with a stannous cloride and with 99mTc, as sodium pertechnetate (99mTcONa). Plasma (P) and cells (C) are isolated by centrifugation. Samples of P and C are also precipitated with trichloroacetic acid (TCA 5%) and soluble (FS-P; FS-C) and isoluble (FI-P; FI-C) fractions are separated. In the bioavailability analysis, the extract or NaCl 0.9% solution is administrated into Wistar rats (gavage) during 15 days. Sodium pertechnetate was administered and after 10 min, the animals are sacrificed, the organs were isolated, the radioactivity determined in a well counter, and the percentages of radioactivity per gram (%ATI/g) in the organs are calculated.
  
  
  RESULTS
  The hiperico extract decreasedsignificantly (P < 0.05) the %ATI in the cells, cellular insoluble fraction and plasma insoluble fraction. The biodistribution was significantly (P < 0.01) decreased in bone, muscle and thyroid and significantly (P < 0.05) increased in pancreas.
  
  
  CONCLUSIONS
  The analysis of the results indicates that in studied extract should have substances that should oxidize the stannous ion, reducing the fixation of the 99mTc on the erythrocytes and plasma and cellular proteins. Moreover, it could produce metabolic alterations with influence in the uptake of the radiopharmaceutical 99mTcO4Na in bone, muscle, pancreas and thyroid.
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde da Universidade Federal do Rio Grande do Norte. sdsfilho@terra.com.br
authors.forename: Sebastião David
authors.initials: SD
authors.lastname: Santos-Filho
authors.forename: Mario
authors.initials: M
authors.lastname: Bernardo-Filho
mesh_terms: D000818:Animals; D001682:Biological Availability; D001842:Bone and Bones / Q000378:metabolism; D004912:Erythrocytes / Q000000981:diagnostic imaging* / Q000378:metabolism; D020902:Hypericum / Q000737:chemistry*; D007553:Isotope Labeling; D008297:Male; D009132:Muscles / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D051381:Rats; D013670:Sodium Pertechnetate Tc 99m / Q000493:pharmacokinetics*; D013961:Thyroid Gland / Q000378:metabolism; D017971:Tin Compounds / Q000097:blood; D014018:Tissue Distribution
chemical_list: D010936:Plant Extracts; D019275:Radiopharmaceuticals; D017971:Tin Compounds; C023599:stannous chloride; D013670:Sodium Pertechnetate Tc 99m