The serum cortisol response to intravenous synthetic ACTH (tetracosactrin) was assessed in 15 healthy adult cats. Mean cortisol levels showed a significant (P<0.001) rise at 60 minutes and peaked at 180 minutes. At 120 and 180 min‐ utes mean cortisol levels were significantly (P<0.001) higher than at 60 minutes. The time of peak cortisol response in individual cats varied between 120 and 240 minutes, but nine (60 per cent) peaked at 180 minutes. In response to the ACTH the cats showed a rise in cortisol levels of between 160 and 1360 per cent. No significant rise in cortisol levels was seen in five cats following administration of sterile saline.

No abstract

1 The involvement of phospholipase D (PLD) in the 5-hydroxytryptamine 5-HT 1B /5-HT 1D -signalling pathway was assessed in the rabbit isolated mesenteric artery. 2 RT ± PCR analysis of mesenteric smooth muscle cells revealed a strong signal corresponding to mRNA transcript for the 5-HT 1B receptor. The PCR fragment corresponded to the known sequence for the 5-HT 1B receptor. No signal corresponding to 5-HT 1D mRNA was detected. 6 5-HT (0.1 ± 1 mM) abolished forskolin (1 mM) stimulated increases in cyclic AMP (15 fold increase), an action which was pertussis toxin-sensitive. 7 Therefore, in the presence of raised extracellular potassium 5-HT can stimulate PLD via 5-HT 1B receptors in the rabbit mesenteric artery. This action requires extracellular calcium and the activation of protein kinase C. These characteristics are identical to the pro®le for 5-HT 1B /5-HT 1D -receptor evoked contraction in vascular smooth muscle cells, suggesting a role for PLD in this response to 5-HT.

CSII may be a viable alternative to multiple daily injections for maintaining glycemic control in patients with IDDM who require intensive insulin therapy.