The Relationship between Glucagon Receptors and Metabolic Profile in Two Strains of Rats: Wistar-Furth and Sprague-Dawley

Abstract

We studied glucagon and insulin binding to isolated hepatocyte receptors in Wistar-Furth (WF) and Sprague-Dawley (SD) rats, using '251-labeled hormones. Hepatocytes from WF rats bound more glucagon than hepatocytes from SD rats. There were no differences in insulin binding. These observations prompted us to investigate other strain differences. Fasting and nonfasting serum glucose, glucagon, insulin, and growth hormone were measured. WF animals had a lower fasting glucose and higher fasting glucagon than SD animals, while SD rats had higher nonfasting insulin levels and a higher hepatic glycogen content. Total hepatic glucose production in response to glucagon ( M ) was greater in WF than in SD rats, while glucagon-stimulated gluconeogenesis from alanine was the same in the two groups of animals. We concluded that the decreased glucagon binding does not play a significant role in the maintenance of serum glucose or in the gluconeogenetic response glucagon, and that neither these responses nor the serum glucagon levels appears to be correlated with the number of glucagon receptors. We conclude further that different animal strains of the same species may differ in their biologic responses. Downloaded from 32-37, 1985. tuitary gland: Effect of age, sex, and hormonal state. Endocrinology (Baltimore) 81: 195-204, 1967. 10. Zahlten RN, Kneer NM, Stratman FW, Lardy HA. The influence of ammonium and calcium ions on

Regulation of fatty acid and carbohydrate metabolism by insulin, growth hormone and tri-iodothyronine in hepatocyte cultures from normal and hypophysectomized rats

“…This agrees with the previous report, which showed significant changes only after 4 days culture with growth hormone [12]. Hepatocytes from Wistar rats Previous studies have indicated that there are differences in the plasma concentrations of glucose, insulin, glucagon and possibly also growth hormone, and differences in glucagon receptors, between the Sprague-Dawley and Wistar strains of rats [25]. Experiments were carried out with hepatocytes from normal Wistar rats (Table 3) under similar conditions to those used above for Sprague-Dawley rats (Tables 1 and 2).…”

“…It has been shown that a single injection of growth hormone causes acute down-regulation of hepatic growthhormone receptors in hypophysectomized rats [34]. The variability in the effects of growth hormone in hepatocytes from Wistar rats may be related to the variability in plasma growth-hormone concentration in this strain of rats [25].…”

“…It is recognized that there are differences in the plasma concentrations of various hormones and also in hormone receptors between the commonly used Wistar and Sprague-Dawley strains of rats [25]. There have been few comparative studies between these two strains, although frequently discrepancies between results from different laboratories are attributed to the different strains of rats used.…”