title: In vivo effect of insulin on the acute proliferative response of the rat aorta to injury.
abstract: The objective of our study was to investigate the effect of hyperinsulinemia associated with either euglycemia, hypoglycemia, or hyperglycemia on the short-term mitotic activity of arterial smooth muscle cells (SMCs) after aortic injury. The proliferative reaction of arterial SMCs was provoked by the passage of an embolectomy catheter with a tightly inflated balloon. DNA synthesis was measured as DNA specific activity after incubation of the aorta in a medium containing 3[H]thymidine. Unrestrained rats were rendered hyperinsulinemic (4-7 nM versus 0.3 nM in controls) immediately after aortic injury by insulin infusion (10 units/day) and either euglycemic (about 5.6 mM), hyperglycemic (14-17 mM), or hypoglycemic (about 2.8 mM) by adjusting the flow rate of hypertonic glucose (30% wt/vol) that was infused simultaneously. The infusion was performed via a catheter inserted into the jugular vein and lasted 2 or 4 days after the aortic injury. After the injury, SMC mitotic activity was dramatically increased on day 2 in control rats with deendothelialized aortas and declined between days 2 and 4. In euglycemic-hyperinsulinemic and hyperglycemic-hyperinsulinemic rats, SMC proliferation showed the same pattern as in controls. At no time was a significant difference observed among the three groups of rats. In hypoglycemic-hyperinsulinemic rats, SMC mitotic activity increased to a lesser extent than in controls on day 2 after deendothelialization. These data indicate that hyperinsulinemia with or without hyperglycemia does not stimulate the early stages of arterial SMC proliferation in the rat although a long-lasting effect of hyperinsulinemia cannot be excluded.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Laboratory of Pathophysiology of Nutrition, Broussais Hospital, University of Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Ridray
authors.forename: A
authors.initials: A
authors.lastname: Ktorza
authors.forename: L
authors.initials: L
authors.lastname: Picon
authors.forename: L
authors.initials: L
authors.lastname: Capron
mesh_terms: D000818:Animals; D001011:Aorta / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D001786:Blood Glucose / Q000032:analysis; D002404:Catheterization; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014947:Wounds and Injuries / Q000209:etiology
chemical_list: D001786:Blood Glucose; D007328:Insulin; D004247:DNA