Impact of excess aldosterone on glucose homeostasis in adult male rat.
BACKGROUND
Clinical and experimental data demonstrate that excess aldosterone and insulin interact at target tissues. It has been shown that increased levels of aldosterone contribute to development of insulin resistance and thus act as a risk factor for the development of type-II diabetes mellitus. However, the molecular mechanisms involved are yet to be identified. The present study was designed to assess the impact of excess aldosterone on GLUT2 and GLUT4 gene expression and glucose uptake in liver and skeletal muscles (gracilis and quadriceps) of adult male rat.


METHODS
Healthy adult male albino rats of Wistar strain (Rattus norvegicus), weighing 180-210 g were used in the present study. The rats were divided into two groups (control and aldosterone treated) each consisting of five animals. Rats were treated with aldosterone at a dose of 10 microg/kg body weight, subcutaneously, twice daily at 8 AM and 6 PM for 15 days.


RESULTS
Excess aldosterone impaired the rate of glucose uptake through defective expression of GLUT2 and GLUT4 genes and also decreased translocation of GLUT4 to the plasma membrane.


CONCLUSIONS
Excess aldosterone has an adverse effect on glucose uptake in liver and skeletal muscle and the defective expression of GLUT2 and GLUT4 appears to be responsible for such changes.
Selvaraj
Jayaraman
J
Department of Endocrinology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai 600113, India.
Muthusamy
Thirupathi
T
Srinivasan
Chinnapaiyan
C
Balasubramanian
Karundevi
K
D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000737:chemistry; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003847:Deoxyglucose / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D051273:Glucose Transporter Type 2 / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D002250:Carbon Radioisotopes; D051273:Glucose Transporter Type 2; D051275:Glucose Transporter Type 4; D012333:RNA, Messenger; D000450:Aldosterone; D006003:Glycogen; D003847:Deoxyglucose; D005947:Glucose