Effect of 3-hydroxy-4-1(H)pyridone on the basal and thyrotropin-releasing hormone-stimulated release of thyroid-stimulating hormone from perifused anterior pituitary fragments.
This study investigated the direct effect of 3-hydroxy-4-1(H)-pyridone (DHP), the breakdown product of mimosine in the rumen, on thyroid-stimulating hormone (TSH) secretion by perifusion of rat anterior pituitary fragments. During a 2-h perifusion with thyrotropin-releasing hormone (TRH), the total release of TSH increased linearly (P less than 0.05, r = 0.966) with increasing concentration of TRH from 1 to 100 ng/ml. The release was maximal at 100 ng/ml. There were no differences in total basal TSH release among control and DHP-treated pituitary fragments. DHP at concentrations of 1, 10, and 100 micrograms/ml had no significant effect on the TSH response to TRH. However, DHP at the concentration of 1 mg/ml significantly suppressed the TSH response to TRH administered continuously or as a 10-min pulse. These results suggest that DHP modulates the pituitary thyrotroph's response to TRH.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D010477:Perfusion; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011728:Pyridones / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013972:Thyrotropin / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D011728:Pyridones; C020366:3-hydroxy-4-pyridone; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin