The relationship between mean arterial pressure and vasopressin release.
An acute fall in blood pressure or volume causes release of vasopressin. The graph shows the exponential rise in vasopressin in response to progressive hypotension induced (in normal subjects) by infusion of the ganglion-blocking drug trimetaphan over periods ranging from 15 to 30 minutes. Blood pressure must be reduced by at least ten per cent before any significant rise in vasopressin secretion occurs, although a forty per cent reduction in blood pressure leads to plasma vasopressin concentrations of some one hundred times the normal basal level.
