Effect of simultaneous infusion of a somatostatin analogue, insulin and glucose on serum triglycerides and blood glucose levels in man.
Nine non-diabetic, non-obese, normocholesterolemic normal male subjects with varied triglycerides levels were subjected to a simultaneous infusion test with a synthetic somatostatin analogue [des(Ala1, Gly2)-D-Trp8, D-Asn3, 14-somatostatin], insulin and glucose under ambulatory conditions. The levels of C-peptide reactivity, immunoreactive glucagon and growth hormone were reduced, and the level of immunoreactive insulin remained constant during the infusion. The blood glucose reached a constant value at 110-120 minutes (steady state blood glucose, SSBG) after the commencement of the infusion. The total cholesterol (TC) levels decreased slightly in the 30 minutes after the experiments were begun, and the triglycerides (TG) levels decreased gradually throughout the infusion period, due mainly to the reduction of very low density lipoprotein (VLDL). The most striking finding was the highly significant positive correlation (p less than 0.005, r = 0.868) between SSBG and the serum TG level prior to the infusion. These results indicate an important relationship between insulin sensitivity and serum TG level. High TG level may be regarded as one of the indices of insulin resistance.