Participation de l’apéline à la régulation de l’équilibre hydrique, de l’homéostasie glucidique et des fonctions cardiovasculaires

The discovery of apelin, an endogenous ligand of the orphan APJ receptor, constitutes an important advance in both fundamental research and clinical medicine. Experimental data have shown that apelin has a diuretic effect via its central and renal actions: by inhibiting the phasic activity of vasopressinergic neurons and systemic secretion of vasopressin and its direct effect on the renal microcirculation and probably tubular function. Besides its diuretic action, when injected into the blood stream, apelin decreases blood pressure and increases the contractile force of the myocardium while decreasing pre- and post-load, actions opposing those of vasopressin and angiotensin II. Taken together, these data show that this new circulating vasoactive (neuro)peptide could play a crucial role in maintaining water and electrolyte balance and cardiovascular functions. Finally, a systemic injection of apelin in insulin-resistant mice decreases glycemia and enhances glucose uptake in skeletal muscle and adipose tissue, contributing to homeostatic control of blood glucose. Clinically, the development of non-peptide analogs of the apelin receptor could provide new therapeutic tools potentially useful for the treatment of heart failure, states of water and/or electrolyte retention, and type 2 diabetes mellitus.     

Prise en charge de l’acromégalie évolutive au cours de la grossesse

Pregnancy in acromegalic patients is an infrequent event, due to perturbed gonadotroph function. On the other hand, pregnancy may cause an enlargement of the adenoma or an increase of growth hormone (GH) secretion. We report the case of a 26-year-old woman with a GH-secreting pituitary macroadenoma who was operated by transphenoidal approach. After surgery, she had a persistant acromegaly due to an intrasellar tumour. She was treated by lanreotide. After one year, the patient had married and became pregnant. Lanreotide was stopped when the diagnosis of pregnancy was established. The follow-up of this patient showed a progressive increase of IGF1 level during pregnancy without tumoral syndrome or visual troubles. No metabolic complication was detected. The patient went to term and gave birth to a healthy baby. In postpartum, the IGF1 level was normal, but the brain MRI revealed a 10 mm intrasellar tumour. The pituitary adenoma was not significantly enlarged during pregnancy. Therefore, pregnancy doesn’t influence acromegaly in young women well controlled by medical treatment.