[Circadian rhythm of urinary somatostatin-like immunoreactivity (SLI) and its contents in several organs after oral TRH administration in rats].
Urinary SLI was measured every six hours for twenty four hours in rats fed a regular diet. Previously, we found that the urinary SLI increased after the administration of TRH intravenously. In the present study, in order to reveal the localization of increased SLI, we measured the contents in the hypothalamus, pituitary, thyroid, stomach and pancreas after the oral TRH administration. (1) The rat urinary SLI levels showed a circadian rhythm. The maximum level of SLI was collected from 0.00--6.00 a.m. (89.4 +/- 8.6 pg/6 hrs) (mean +/- SEM). This level was reduced during the daytime 6.00 a.m.--6.00 p.m. The minimum level was obtained from 6.00 p.m.--0.00 a.m. (49.3 +/- 7.2 pg/6 hrs). (2) The rats were decapitated at three and six hours after the oral TRH (500 micrograms/ml) administration. The SLI content was measured by RIA after extraction from each organ with 2.5 ml of 2 M acetic acid. The pituitary SLI content was reduced three hours after the oral TRH administration. The thyroid SLI content was reduced six hours after the oral TRH administration. The hypothalamic, gastric and pancreatic SLI contents didn't change at three and six hours after the oral TRH administration. As the result, the data suggest that augmentation by the oral TRH administration of urinary SLI was caused by its effect on the both the pituitary and the thyroid.
D000284:Administration, Oral; D000818:Animals; D002940:Circadian Rhythm; D005753:Gastric Mucosa / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D010179:Pancreas / Q000378:metabolism; D010455:Peptides / Q000378:metabolism / Q000652:urine*; D010902:Pituitary Gland / Q000378:metabolism; D051381:Rats; D013961:Thyroid Gland / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*
D010455:Peptides; C029993:somatostatin-like peptides; D013973:Thyrotropin-Releasing Hormone