Size matters. Workshop on growth control in development and disease.

Abstract

This Arolla workshop took place between 18 and 24 August 2003, and was organized by E. Hafen, D. Duboule and C. Kenyon ![][1] A recent workshop entitled Growth Control in Development and Disease brought together around 90 scientists in the beautiful village of Arolla in the Swiss Alps. During this meeting, growth control was discussed from the perspectives of evolution, metabolism, ageing and cancer biology. From formal presentations to poster sessions, and mountain hikes to late‐night discussions, the participants indulged in multidisciplinary scientific exchanges that stimulated innovative insights and forged new collaborations. Here, I present a few highlights from the meeting. ### Systemic control of growth by hormones and growth factors Whereas the growth of single‐cell organisms, such as yeast, is mainly regulated by nutrient availability, the growth of higher eukaryotes is dependent on the integration of many cell‐extrinsic cues, which include hormones, growth factors and nutrients (Kimball & Jefferson, 2000; Rohde et al , 2001). Indeed, the systemic control of metazoan growth by hormones and nutrients is a topic of intense investigation in the growth‐control field. F. Nijhout (Durham, NC, USA) discussed how the final body size of insects is determined by the size at which a larva stops feeding and switches on the pupal fate (Nijhout, 2003). This transition from larval to pupal development requires the decay of juvenile hormone (JH) and secretion of the moulting hormone ecdysone, the production of which, in turn, is regulated by the neurosecretory prothoracicotropic hormone (PTTH). Interestingly, different insects use diverse strategies to control the production of PTTH. In the tobacco hornworm Manduca sexta , the secretion of PTTH is induced by the cessation of JH, which, in turn, is tightly associated with the attainment of a well‐defined ‘critical weight’. In certain species of Hemiptera, such as the milkweed bug Oncopeltus fasciatus , PTTH secretion is controlled by abdominal stretch receptors that are … [1]: /embed/graphic-1.gif