Effect of phosphatase inhibitors on estrogen receptors in the rat testis.
Testicular estrogen receptors were measured in the presence of phosphatase inhibitors, molybdate (MoO4=), wolframate (WO4=) and fluoride (F-), under different experimental conditions. At 0-4 degrees C, MoO4= was able to partially replace the stabilizing action of dithiothreitol (DTT) on cytosolic estrogen binding activity, suggesting a protective effect on reduced sulfhydryl groups. At 25 degrees C in the presence of DTT, the effect of MoO4= was observed in homogenates and low speed supernatants, being uneffective in cytosol. A possible mechanism of action through inhibition of phosphatase activity was supported by the use of WO4=. Acid phosphatase activity was inhibited in the presence of these agents, whereas alkaline phosphatase was unaffected. The addition of MoO4= also caused a significant inhibition of proteolytic activity. These results suggest that MoO4= would stabilize testicular estrogen binding activity through, at least, three mechanisms: 1) protection of reduced sulfhydryl groups; 2) inhibition of acid phosphatase, and 3) inhibition of proteolytic activity.
de las Heras
M A
MA
Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina.
Calandra
R S
RS
D000818:Animals; D004226:Dithioerythritol / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D005459:Fluorides / Q000494:pharmacology*; D008297:Male; D008982:Molybdenum / Q000494:pharmacology*; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors; D051381:Rats; D011919:Rats, Inbred Strains; D011959:Receptors, Estradiol / Q000187:drug effects* / Q000378:metabolism; D011960:Receptors, Estrogen / Q000187:drug effects*; D013737:Testis / Q000378:metabolism*; D014414:Tungsten / Q000494:pharmacology*
D011959:Receptors, Estradiol; D011960:Receptors, Estrogen; D004958:Estradiol; D004226:Dithioerythritol; D008982:Molybdenum; C024687:sodium molybdate(VI); D010744:Phosphoric Monoester Hydrolases; D005459:Fluorides; D014414:Tungsten