Brain TRH and Cyclo (His-Pro) and brain protein in the newborn rat are altered by maternal liquid protein feeding.

Liquid protein diet (LPD) has been shown previously to produce maternal and fetal weight loss and fetal congenital anomalies, including cataracts and craniofacial malformations. Therefore, to examine the effects of LPD in pregnancy upon the central nervous system of pups, pregnant dams were fed either a 20% casein diet ad libitum, a 20% LPD, or pair-fed with a 20% casein diet. LPD was associated with significant maternal weight loss, and pups had significantly lower birth weights (5.14 +/- 0.64) than pups from the pair-fed controls (5.70 +/- 0.46, p less than 0.05). Total brain protein content was reduced significantly in pups of both sexes from pregnant fed LPD. Moreover, the concentrations of two brain peptides neurotransmitters, thyrotropin-releasing hormone (TRH), and its biologically active metabolite, histidyl-proline diketopiperazine Cyclo (His-Pro), were elevated in the pups from LPD-fed mothers. In contrast, there was no significant difference in brain protein or brain peptides in pups from pair-fed mothers vs. pups from mothers fed ad libitum. These data suggest that qualitative alterations of the protein component in maternal dietary composition have deleterious effects upon the ontogeny of the rat fetal CNS, as reflected by reduced total protein and elevated concentrations of TRH and Cyclo (His-Pro).