RESUMEN
This study investigated the differences in health outcomes associated with ferulic acid (FA) supplementation in animals before the induction of diabetes with streptozotocin (STZ) treatment and post-STZ treatment. 18 male Wistar rats were equally distributed into three groups: groups 1 and 2 received FA (50 mg/kg body weight) supplementation one week before STZ treatment (60 mg/kg body weight, intraperitoneal) and one week after STZ treatment, respectively; group 3 received STZ without FA supplementation. FA supplementation was continued for 12 weeks after STZ treatment. The results indicated no difference in glucose and lipid profile with FA supplementation. However, FA supplementation reduced lipid and protein oxidative damage in the heart, liver and pancreas and increased glutathione in the pancreas. The results indicate that while oxidative damages were positively affected by FA, it was not sufficient to improve metabolic markers of diabetes.
RESUMEN
The physiological role of prolactin (PRL) in the heart, and in particular the diabetic heart, are largely unknown. The effects of PRL on ventricular myocyte shortening and Ca2+ transport in the streptozotocin (STZ) - induced diabetic and in age-matched control rats were investigated. PRL receptor protein, myocyte shortening, intracellular [Ca2+], L-type Ca2+ current were measured by Western blot, cell imaging, fluorescence photometry and whole-cell patch-clamp techniques, respectively. Compared to normal Tyrode solution (NT), PRL (50 ng/ml) significantly (p < 0.05) increased the amplitude of shortening in myocytes from control (7.43 ± 0.38 vs. 9.68 ± 0.46 %) and diabetic (6.57 ± 0.24 vs. 8.91 ± 0.44 %) heart (n = 44-49 cells). Compared to NT, PRL (50 ng/ml) significantly increased the amplitude of Ca2+ transients in myocytes from control (0.084 ± 0.004 vs. 0.115 ± 0.007 Fura-2 ratio units) and diabetic (0.087 ± 0.007 vs. 0.112 ± 0.006 Fura-2 ratio units) heart (n = 36-50 cells). PRL did not significantly alter the amplitude of caffeine-evoked Ca2+ transients however, PRL significantly increased the fractional release of Ca2+ in myocytes from control (21 %) and diabetic (14 %) and heart. The rate of Ca2+ transient recovery following PRL treatment was significantly increased in myocytes from diabetic and control heart. Amplitude of L-type Ca2+ current was not significantly altered by diabetes or by PRL. PRL increased the amplitude of shortening and Ca2+ transients in myocytes from control and diabetic heart. Increased fractional release of sarcoplasmic reticulum Ca2+ may partly underlie the positive inotropic effects of PRL in ventricular myocytes from control and STZ-induced diabetic rat.
