CYTOSOLIC CA PROFILE OF RESTING AND THROMBIN-STIMULATED PLATELETS FROM BLACK-WOMEN WITH NIDDM

In this study, human platelets were used as a cellular model for explo ring cytosolic free Ca (Ca-i) regulation in non-insulin-dependent diab etes mellitus (NIDDM). Ca-i levels were monitored in resting and throm bin-stimulated platelets from obese females with NIDDM; obese, nondiab etic women, and nonobese, nondiabetic women. All subjects were black. Significant and marked elevation of basal Ca-i levels was observed in platelets from the diabetic subjects when no aspirin was used during p latelet isolation. However, no significant differences were observed i n Ca-i between aspirin-treated platelets from women with NIDDM and pla telets from nondiabetic women. The rate of the Ca-i return to basal le vel after thrombin stimulation was significantly lower in platelets fr om the diabetic subjects, suggesting an abnormality in platelet Ca ext rusion or sequestration in NIDDM. Platelet Ca-i levels positively corr elated with low-density lipoprotein cholesterol/high-density lipoprote in cholesterol ratio (LDL/HDL) and fasting blood glucose. These findin gs suggest abnormalities in platelet Ca-i homeostasis in NIDDM that ar e influenced by the serum lipid profile and perhaps glucose.