Changes in plasma β-cell tropin concentrations during pregnancy in rats

Abstract

Abstract The mechanisms which initiate and maintain the energy partitioning into maternal tissues during pregnancy are unknown. The present study shows that in each of the weeks prior to pregnancy in the rat, plasma β-cell tropin (βCT) concentrations (nmol/l) were 0·68±0·10, 0·61 ±0·14 and 0·73±0·11 (n=11, mean±s.e.m.). During early (1-3 days) pregnancy the concentration rose to 1·32 ±0·26 and by early-mid (7–10 days) pregnancy they had increased to 1·96 ±0·41. By mid-late (14–17 days) pregnancy plasma βCT concentration had declined to the prepregnancy concentrations (0·67 ± 0·16). This mid-term increase in the circultating concentration of the lipogenic hormone βCT may contribute to the deposition of lipid associated with the early period of gestation. The increased circulating βCT could be derived from the pituitary gland neurointermediate lobe or by secretion from the placenta. It should be emphasised that the measurements in the present study represent a 'snap-shot' at discrete intervals and do not provide information about the dynamic hormonal interplay which occurs physiologically. Journal of Endocrinology (1995) 146, 177–182