Effects of dexamethasone on pancreatic growth and thyroliberin (TRH) content in neonatal rat pancreas.
Thyrotropin-releasing hormone (TRH) is also present in pancreatic B-cells and its role and regulation here remain unclear. The rat pancreas displays a peculiar ontogenetic pattern for TRH with a rapid increase after birth up to postnatal day 3 when TRH peak is reached. In the present study, dexamethasone (DXM) treatment (1 microgram/100g BW/day) resulted in an increase of pancreatic weight and retardation of the peak of pancreatic TRH concentration by two days. The TRH-degrading system (either in the 10,000 x g supernatant or in the pellet of pancreatic homogenate) was not stimulated by in vivo DXM treatment. In DXM-treated rats, plasma TSH levels were significantly decreased after postnatal day 1. Plasma glucose concentration was increased on day 1 (i.e. 24 h after the first DXM injection) and decreased to the control level on postnatal day 3. Pancreatic insulin levels were decreased on postnatal day 3 compared to the controls. These results indicate that DXM affects TRH in the neonatal rat pancreas; this effect is probably not mediated through modulation of TRH-degrading activity. The stimulation of pancreatic growth after DXM treatment might be related to the effect on the TRH system.
Benický
J
J
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Strbák
V
V
D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D010179:Pancreas / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*
D013973:Thyrotropin-Releasing Hormone; D003907:Dexamethasone