Endocrine Abstracts

Introduction: Pregnancy leads to extensive adaptations in the female’s body, by changing the secretion and responses to several hormones. GH is required for fetal nutrition, growth during pregnancy and for mammary development and lactation, although its central effects are not completely clarified.

Aim: The aim of this study was to investigate whether central GH signaling regulates physiological and metabolic adaptations during pregnancy.

Methods: We produced mice carrying ablation of the GH receptor (GHR) either in neurons (GHR^flox/flox/Nestin^Cre) or in cells that express the leptin receptor (GHR^flox/flox/LepR^Cre). These females were mated and, when the first day of gestation was identified via the identification of the copulatory plug, they were individualized and further studied.

Results: Pregnant GHR^flox/flox/Nestin^Cre females had higher food intake, weight gain, insulin sensitivity (ITT), and IGF-1 concentrations during pregnancy as well as lower adiposity, serum concentrations of insulin and leptin. During the lactation period, these females presented higher deposition of subcutaneous fat. The GHR deletion in leptin receptor cells also resulted in higher food intake and reduced adiposity in all evaluated periods. In addition, a better glucose tolerance, higher insulin sensitivity and lower serum concentrations of insulin and leptin were also observed in pregnant GHR^flox/flox/LepR^Cre females.

Conclusion: These results indicate that GH plays a role in metabolic control during gestation. Other experiments are being conducted to better clarify the mechanisms involved.

Keywords: energy balance, gestation, growth hormone, cytokine signaling.

Financial support: CNPq e FAPESP.