Figure 2.

Results from two ewes showing GnRH concentration profiles (•) in CSF harvested simultaneously from cannulae located in the optic, infundibular, or pineal recess during two periods of 4 h for each cannula. Corresponding LH secretion in the peripheral blood over the 12 h of the sampling period is also shown (▪). The locations of the cannulae in the ventricular system are illustrated in the schematic. The horizontal dashed line indicates the detection limit of the GnRH assay, and values set at this limit are noted by an open circle (○). The vertical dotted lines facilitate visual alignment of the values between the cannulae and jugular blood. Pulses are noted by an arrowhead (▾). The asterisk (*) indicates a missing sample.