Peripartum maternal and foetal ghrelin, growth hormones, IGFs and insulin interrelations

Abstract

Ghrelin may influence GH secretion and is associated with insulin sensitivity. In pregnancy, placental growth hormone (PGH) replaces GH. The aim of this study was to investigate the relationship between PGH and ghrelin and their relationship to insulin sensitivity in pregnancy. Prospective, descriptive study. Thirty-seven singleton pregnant and six twin pregnant women Maternal blood samples were drawn before and 2 days after elective caesarian section (CS). Serum total ghrelin, PGH, GH, GH-binding protein, insulin and IGF-I and IGF-II, and plasma glucose were determined. Insulin sensitivity indices (ISIs) were calculated. Cord blood samples were drawn at delivery for ghrelin determination. Serum ghrelin only displayed a minimal, although statistically significant, decrease after CS. Prior to delivery serum PGH increased by 25% during fasting, and was undetectable the day after CS. Serum levels of GH were low until 48 h after CS. No significant correlations were detected between PGH or ghrelin and ISIs, although a trend was observed for ghrelin. Twin pregnancies had higher PGH levels than singletons; however, levels of IGFs were similar. In cord blood, ghrelin levels were higher in arterial than venous samples. Maternal ghrelin levels were only minimally affected by parturition, suggesting that maternal ghrelin is not involved in the transition from PGH to GH secretion. The increased arterial ghrelin levels in the foetus suggest foetal ghrelin production. Serum PGH appears to be influenced by fasting. Finally, elevated PGH levels in twin pregnancies do not appear to affect maternal IGF levels.