Developmental pattern of TRH-degrading activity and TRH content in rat pancreas.
Thyrotrophin-releasing hormone (TRH), like several other neuropeptides, has been detected in the gastro-intestinal tract of adult rats. More recently, elevated concentrations of TRH have been found in the neonatal rat pancreas. This study was undertaken to evaluate pancreatic TRH degrading activity (TRH-DA) in infant rats from birth until adult life. Pancreatic TRH of age-matched rats was also measured by radioimmunoassay. TRH-DA was present in normal adult rat pancreas; though absent at birth and in the early postnatal period up to day 7, this activity was detected during the remainder of the developmental period. TRH content (pg +/- SEM per pancreas) was 1139 +/- 88 on day 1, reached a peak value of 7360 +/- 758 at day 2 and then decreased steadily to adult level. TRH-DA has been found to be present at birth in hypothalamus and liver but not in plasma. The developmental patterns of TRH-DA in plasma and in pancreas were parallel and seem to be thyroid hormone dependent. The absence of TRH-DA in the neonatal pancreas may also be related to the high TRH concentrations detected in this organ during the neonatal period.
D000375:Aging; D000818:Animals; D002855:Chromatography, Thin Layer; D010179:Pancreas / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D013961:Thyroid Gland / Q000378:metabolism; D013972:Thyrotropin / Q000097:blood; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin; D013974:Thyroxine