Vasilatos-Younken, Regina - PENNSYLVANIA STATE UNIVER
Submitted to: International Symposium on Avian Endocrinology Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 1996
Publication Date: N/A
The purpose of this study was to compare the metabolic and endocrine responses of male broiler chickens to an intravenous injection of either cIGF-I, hIGF-I or cIGF-I-LR3 (an IGF-I analogue). At 5 weeks of age, chickens were surgically implanted with a jugular cannula. Following an 8 hr fast, equimolar amounts of cIGF-I, hIGF-I and cIGF-I-LR3 (100, 102 and 126 mg/kg bwt, respectively) were infused. Control birds were infused with an equal volume of saline. Plasma samples were collected at selected intervals pre- and post-infusion and analyzed for various hormonal and metabolite parameters as well as insulin- like growth factor binding protein (IGFBP) activity. Similar hypoglycemic responses (50%) were induced by cIGF-I and hIGF-I, and to a lesser extent (30%) by LR3. A concomitant decline in insulin concentrations was noted. GH levels were differentially affected following growth factor treatment in that cIGF-I and hIGF-I were similarly depressed, while only minor decreases in GH were observed following LR3 treatment. Regardless of treatment, plasma T4 and T3 declined during the sampling period. Significant increases in plasma glucagon and free fatty acid concentrations were observed, while triglyceride levels were unaffected. Changes in IGFBP activity were noted. Similar metabolic and endocrine responses were elicited by cIGF-I and hIGF-I, while less dramatic changes in these parameters were induced by cIGF-I- LR3.