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E. Sandberg, B. Ahrén, D. Tendler and S. Efendic

Abstract. Gastric inhibitory polypeptide (GIP), cholecystokinin (CCK), and vasoactive intestinal polypeptide (VIP) stimulate insulin secretion. In this study we investigated whether CCK-33 and VIP could influence the insulinogenic effect of simultaneously administered GIP and 6.7 mmol/l glucose in the perfused rat pancreas. We found that at 0.1 nmol/l, GIP markedly potentiated glucose-induced insulin release whereas CCK-33 and VIP had a weak stimulatory effect and only during the late phase. At this low dose level, CCK-33 potentiated but VIP inhibited the late phase of insulin release stimulated by glucose and GIP. At 1.0 nmol/l, GIP, CCK-33, and VIP markedly potentiated both phases of glucose-induced insulin secretion. At this dose level CCK-33 and GIP exerted additive stimulatory effects on the late phase of insulin release triggered by glucose. In contrast, 1.0 nmol/l VIP inhibited insulin secretion augmented by glucose and GIP. In summary 1) GIP, CCK-33 and VIP all potentiate glucose-induced insulin secretion from the perfused rat pancreas, and 2) CCK-33 potentiates and VIP inhibits GIP-induced insulin secretion. We suggest that interactions of this kind are of importance for the precise regulation of insulin secretion.

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J. Szecówka, V. Grill, E. Sandberg and S. Efendić

Abstract.

The effects of gastric inhibitory polypeptide (GIP) on insulin secretion as well as on the intra-islet accumulation of [3H]cyclic AMP were investigated in isolated pancreatic islets of the rat. In the presence of 6.7 mmol/l of glucose, 3.0 and 30 nmol/l of GIP induced both insulin and [3H]cyclic AMP responses, while lower and higher concentrations of the peptide were ineffective. A coupling of the two parameters was also found with regard to interaction between glucose and GIP. Thus while 30 nmol/l of GIP was stimulatory together with 6.7, 16.7 or 33.3 mmol/l of glucose, the peptide stimulated neither insulin release, nor the accumulation of [3H]cyclic AMP in the presence of a low concentration of glucose (3.3 mmol/l).

The concomittant release of insulin and somatostatin was studied in the perfused pancreas in order to assess a possible influence by somatostatin on the dose-response pattern for GIP-induced insulin release. In this preparation 1.0 to 10 nmol/l of GIP stimulated insulin and somatostatin secretion; however while these concentrations were equipotent on insulin release, 10 nmol/l of GIP stimulated somatostatin release more than 1 nmol/l, indicating differences in dose-reponse curves for the GIP-induced stimulation of the two hormones.

It is concluded that 1) modulation of GIP-induced insulin release is coupled to changes in cyclic AMP response in the islet, 2) GIP-induced somatostatin secretion may influence the concomittant insulin response.

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Claus H Gravholt, Niels H Andersen, Gerard S Conway, Olaf M Dekkers, Mitchell E Geffner, Karen O Klein, Angela E Lin, Nelly Mauras, Charmian A Quigley, Karen Rubin, David E Sandberg, Theo C J Sas, Michael Silberbach, Viveca Söderström-Anttila, Kirstine Stochholm, Janielle A van Alfen-van derVelden, Joachim Woelfle, Philippe F Backeljauw and On behalf of the International Turner Syndrome Consensus Group

Turner syndrome affects 25–50 per 100,000 females and can involve multiple organs through all stages of life, necessitating multidisciplinary approach to care. Previous guidelines have highlighted this, but numerous important advances have been noted recently. These advances cover all specialty fields involved in the care of girls and women with TS. This paper is based on an international effort that started with exploratory meetings in 2014 in both Europe and the USA, and culminated with a Consensus Meeting held in Cincinnati, Ohio, USA in July 2016. Prior to this meeting, five groups each addressed important areas in TS care: 1) diagnostic and genetic issues, 2) growth and development during childhood and adolescence, 3) congenital and acquired cardiovascular disease, 4) transition and adult care, and 5) other comorbidities and neurocognitive issues. These groups produced proposals for the present guidelines. Additionally, four pertinent questions were submitted for formal GRADE (Grading of Recommendations, Assessment, Development and Evaluation) evaluation with a separate systematic review of the literature. These four questions related to the efficacy and most optimal treatment of short stature, infertility, hypertension, and hormonal replacement therapy. The guidelines project was initiated by the European Society of Endocrinology and the Pediatric Endocrine Society, in collaboration with the European Society for Paediatric Endocrinology, the Endocrine Society, the European Society of Human Reproduction and Embryology, the American Heart Association, the Society for Endocrinology, and the European Society of Cardiology. The guideline has been formally endorsed by the European Society of Endocrinology, the Pediatric Endocrine Society, the European Society for Paediatric Endocrinology, the European Society of Human Reproduction and Embryology and the Endocrine Society. Advocacy groups appointed representatives who participated in pre-meeting discussions and in the consensus meeting.