Effect of age on insulin-induced endothelin release and vasoreactivity in hypertriglyceridemic and hypertensive rats.
In the present paper, the age-related changes in the vasoconstrictive endothelin-mediated response to insulin in aortas of normal and hypertensive, hypertriglyceridemic, hyperinsulinemic (HTG) rats were studied. To develop HTG rats, weanling male Wistar animals were given 30% sucrose in their drinking water for 4, 6, 12 and 18 months. Blood pressure was increased in HTG rats for up to 12 months showing a maximum at 6 months (138.9+/-0.8 mmHg). In vitro contractions were elicited with 40 mM KCl in the presence and absence 50 microU/ml insulin and of endothelin-receptor antagonists BQ123 and BQ788. Tension development to KCl was not modified during aging in control rats but was increased at 4 and 6 months in HTG rats. Increased endothelin release induced by insulin remained constant in normal rats, while in HTG rats it was higher than in controls at all ages. ET(A) blocker participation alone increased during aging in control rats while both receptor blockers participated in HTG rats. Our results suggest that the vasoconstrictive capacity to KCl plus insulin decreases during aging and that this decrease is greater in HTG rats. The participation of endothelin receptors in the aging process differs in control and HTG rats.
Rubio
María Esther
ME
Department of Physiology, Instituto Nacional de Cardiología 'Ignacio Chávez', Juan Badiano 1, Colonia Seccion 16, 14080 Mexico City DF, Mexico.
Baños
Guadalupe
G
Díaz
Eulises
E
Guarner
Verónica
V
D000375:Aging / Q000502:physiology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000378:metabolism*; D006973:Hypertension / Q000378:metabolism / Q000503:physiopathology*; D015228:Hypertriglyceridemia / Q000378:metabolism / Q000503:physiopathology*; D007004:Hypoglycemic Agents / Q000097:blood / Q000494:pharmacology; D007328:Insulin / Q000097:blood / Q000494:pharmacology; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011189:Potassium Chloride / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology; D015431:Weight Loss / Q000187:drug effects
D000959:Antihypertensive Agents; D001786:Blood Glucose; D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D007004:Hypoglycemic Agents; D007328:Insulin; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D014280:Triglycerides; C086539:BQ 788; D011189:Potassium Chloride; C072247:cyclo(Trp-Asp-Pro-Val-Leu)