High GGT liver flow test

I am a 43year old male 5'8" 168lb. I am healthy however my blood presure is high due to hereditory factors (160/110 before medication to control it). I do however have very high GGT levels and moderately high SAP levels from many blood tests over the last 1 1/2 years. A routine bood test in NOV 2000 alerted me to this problem. I have had an Ultrasound, Cat scan and Biopsy which all gave an allclear. I am a moderate alcohol drinker but have never smoked.
Results are as follows.
Date/Tot Prot/ALB/GLOB/TOT BIL/SAP/AST/ALT/GGT
1DEC00/78/44/34/14/389/36/69/1103
12DEC00/80/44/36/13/403/51/80/1113
2FEB01/78/47/31/15/435/47/91/1204
I don't have the results from the last few tests except 1245u/l for the GGT last week. I am now on a no alcohol intake for a month to see if this helps. Do you have any ideas on what could be the problem?
Gerry