Accession Number : ADA119425

Title :   The Role of Limited Proteolysis of Thyrotropin-Releasing Hormone in Thermoregulation.

Descriptive Note : Final rept.,


Personal Author(s) : Prasad,Chandan

PDF Url : ADA119425

Report Date : Jan 1982

Pagination or Media Count : 16

Abstract : Cyclo (His-Pro) is a biologiclly active cyclic dipeptide derived from thyrotropin-releasing hormone by its limited proteolysis. We have developed a specific radioimmunoassay for this cyclic peptide and shown its presence throughout rat and monkey brains. The normal rat brain concentration of cyclo (His-Pro) ranged from 35-61 pmols/brain. The elution profiles of rat brain cyclo (His-Pro)-like immunoreactivity and synthetic radioactive cycly (His-Pro) following gel filtration, ion-exchange chromatography and high pressure liquid chromatography were similar. An analysis of the regional distribution of cyclo (His-Pro) and TRH in rat and monkey brains exhibited no apparent precursor-product relationship. Studies on the neuroanatomic sites for the thermoregulatory effects of cyclo (His-Pro) suggested that the neural loci responsible for cyclo (His-Pro)-induced hypothermia resides within POA/AHA. The endogenous levels of brain cyclo (His-Pro) were elevated when rats were made either hypothyroid by surgical thyroidectomy or forced to drink alcohol for six weeks. These studies demonstrate that cyclo (His-Pro) is present throughout the central nervous system in physiologically relevant concentrations which can be modified by appropriate physiological and pharamacological manipulations. These data in conjunction with earlier reports of multiple biological activities of exogenous cyclo (His-Pro), suggest that endogenous cyclo (His-Pro) is a biological active peptide and it may plan a neurotransmitter or neuromodulator role in the central nervous system. (Author)

Descriptors :   *Pituitary hormones, *Thyrotropin, *Biosynthesis, *Peptides, *Body temperature, Proteins, Cyclic compounds, Hypothalamus, Hypothermia, Hyperthermia, Heat balance, Endocrinology, Injection, Central nervous system, Concentration(Chemistry), Antibodies, Radioimmunoassay, Distribution, Filtration, Chromatography, Rats, Monkeys

Subject Categories : Biochemistry
      Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE