Hi, Pauline - Nice insulin. The ACTH would be okay for a young horse in the autumn, but as you know, for an already-diagnosed PPID horse, mid-levels are better. Correct on your judgement about autumn and liquid pergolide, but for any newbies reading here, capsules are more stable, and one should increase the pergolide until the horse is at a middle to low-middle normal reading of ACTH all year.
And.... I do hate to say it, but when one sees a "nice" insulin and "nice" glucose (both of which are subject to lower values when not spun soon enough, and when exposed to heat), I just have to make sure the blood handling was okay. If the blood handling is at all suspect, then the true ACTH will be higher as well, and an increase in pergolide is definitely indicated.
Dr. Kellon will have to respond as to the nitty-gritty of the MIRG calculations, because I really don't know. Without the leptin it is hard to be sure if there is IR at baseline (despite the breed). However, as always, it is wise to treat as IR unless proven otherwise. In other words, if Huey were mine, I would assume IR, and hope he is not, no matter what the MIRG says.
.....The query is to do with his IR status. ACTH 49 pg/mL, Glucose 4.8mmol/L (3.3-6.7) and Insulin 10 mu/L (<42) . Leptin & T4 pending. Given his breed- it's unlikely- though not impossible to be IR. His ACTH is a little high - but not too bad considering our time of year & liquid pergolide (Ranvet) has been increased accordingly. Using the IR calculator- the results come back as MIRG indicates IR. MIRG 5.67- so marginally over the cut off number of 5.6. I understand that the MIRG is a pancreatic response proxy, but not sure how it comes into play in this case. I have been researching the files & notes from Dr K courses, however still don't fully understand the implications of MIRG
Would appreciate any further insight.
Sth West Vic
Australia Aug 07
EC Primary Response/Moderator