Background: Body weight tends to rise on institutions of insulin theraphy in type 2 diabetics. one possible reason can be stimulated feelings of hunger but there may also be other reasons for this phenomenon.

Method:Blood pressure and body weight were studied in seventeen (age range 51-73 years) obese type 2 diabetics (81-104 kg) before start of insulin therapy and after two, four and six months on insulin. Blood lipids, blood glucose, HbA_1C, S-potassium, S-sodium, S-bilirubin, S-ALP, S-ALAT and S-GT were followed. Some patients had medication for hypertension. Oral anti-diabetic agents had proved to be insufficient.

Results:There was a significant rise of body weight in all patients (p<0,01) which seemed to level off after two months on insulin. Between four and six months on insulin there was only slight further weight gain. More surprisingly, a rather uniform increase of both diastolic and systolic blood pressure was seen after two months on insulin treatment (p<0,05). After four months blood pressure was back to pre-insulin values.

Conclusions:One possible explanation for temporary increase of blood pressure could be effects of insulin on renal absorption of sodium as in cases of insulin oedemas (DeFronzo 1981, Gupta et al 1992, Singh et al 1999). If so, besides creating feelings of hunger etc, insulin treatment may also to some extent increase body weight by enhancing retention of sodium and water. Further studies are warranted to confirm our findings and preliminary theories.