Somatostatin levels in the central nervous system of the Snell dwarf mouse; is somatostatin excess the primary molecular defect in the dw/dw dwarfism?

The Snell dwarf mouse (dw/dw) shows significantly decreased somatostatin levels in the hypothalamus whereas more or less increased somatostatin concentrations are observed in any central extrahypothalamic sites studied. These opposite results in hypothalamus and extrahypothalamic areas may be linked to the apparently distinct neurohormonal and neuromodulatory functions of somatostatin in the brain. They also provide arguments for the assumption of a primary somatostatin excess which could be related to the dwarf mutation. In hypothalamus, the severe defect in growth hormone of the dwarf mutant may rapidly lead, by failure of a pituitary retro-control, to a reduction in the presumed initially elevated somatostatin levels. In central extrahypothalamic sites, known to escape to GH retro-action, higher somatostatin levels remain.