Chronic thyrotropin-releasing hormone decreases the affinity and increases the number of its own receptor in the spinal cord.
Effect of chronic thyrotropin-releasing hormone (TRH) treatment on the properties of spinal cord TRH-receptor was evaluated by Scatchard analysis of data on the saturation of specific binding of [methyl-His3-3H]TRH. Continuous subcutaneous administration of TRH (0.51 +/- 0.02 mg/kg/day) via an Alzetmini osmotic pump for ten days led to a substantial increase in both Bmax (control: 20.0 +/- 2.9, treated: 36.1 +/- 2.8 fmol/mg protein, P = 0.0018) and Kd (control: 7.6 +/- 0.8 treated: 11.7 +/- 1.8 nM, P = 0.0349) of the binding sites. These data suggest that chronic TRH treatment may not induce desensitization of physiologic/pharmacologic responses of TRH in the spinal cord.
Prasad
C
C
Department of Medicine, Louisiana State University Medical Center, New Orleans 70112.
Spahn
S A
SA
D000818:Animals; D001665:Binding Sites; D006706:Homeostasis; D007279:Injections, Subcutaneous; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D018025:Receptors, Thyrotropin-Releasing Hormone; D013116:Spinal Cord / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D013997:Time Factors
D017981:Receptors, Neurotransmitter; D018025:Receptors, Thyrotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone