TY - JOUR
T1 - Postnatal ontogeny of glucose homeostasis and insulin action in sheep
AU - Gatford, K. L.
AU - De Blasio, M. J.
AU - Thavaneswaran, P.
AU - Robinson, J. S.
AU - McMillen, I. C.
AU - Owens, J. A.
PY - 2004/6/1
Y1 - 2004/6/1
N2 - Glucose tolerance declines with maturation and aging in several species, but the time of onset and extent of changes in insulin sensitivity and insulin secretion and their contribution to changes in glucose tolerance are unclear. We therefore determined the effect of maturation on glucose tolerance, insulin secretion, and insulin sensitivity in a longitudinal study of male and female sheep from preweaning to adulthood, and whether these measures were related across age. Glucose tolerance was assessed by intravenous glucose tolerance test (IVGTT, 0.25 g glucose/kg), insulin secretion as the integrated insulin concentration during IVGTT, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (2 mU insulin·kg-1· min-1). Glucose tolerance, relative insulin secretion, and insulin sensitivity each decreased with age (P < 0.001). The disposition index, the product of insulin sensitivity, and various measures of insulin secretion during fasting or IVGTT also decreased with age (P < 0.001). Glucose tolerance in young adult sheep was independently predicted by insulin sensitivity (P = 0.012) and by insulin secretion relative to integrated glucose during IVGTT (P = 0.005). Relative insulin secretion before weaning was correlated positively with that in the adult (P = 0.023), whereas glucose tolerance, insulin sensitivity, and disposition indexes in the adult did not correlate with those at earlier ages. We conclude that glucose tolerance declines between the first month of life and early adulthood in the sheep, reflecting decreasing insulin sensitivity and absence of compensatory insulin secretion. Nevertheless, the capacity for insulin secretion in the adult reflects that early in life, suggesting that it is determined genetically or by persistent influences of the perinatal environment.
AB - Glucose tolerance declines with maturation and aging in several species, but the time of onset and extent of changes in insulin sensitivity and insulin secretion and their contribution to changes in glucose tolerance are unclear. We therefore determined the effect of maturation on glucose tolerance, insulin secretion, and insulin sensitivity in a longitudinal study of male and female sheep from preweaning to adulthood, and whether these measures were related across age. Glucose tolerance was assessed by intravenous glucose tolerance test (IVGTT, 0.25 g glucose/kg), insulin secretion as the integrated insulin concentration during IVGTT, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (2 mU insulin·kg-1· min-1). Glucose tolerance, relative insulin secretion, and insulin sensitivity each decreased with age (P < 0.001). The disposition index, the product of insulin sensitivity, and various measures of insulin secretion during fasting or IVGTT also decreased with age (P < 0.001). Glucose tolerance in young adult sheep was independently predicted by insulin sensitivity (P = 0.012) and by insulin secretion relative to integrated glucose during IVGTT (P = 0.005). Relative insulin secretion before weaning was correlated positively with that in the adult (P = 0.023), whereas glucose tolerance, insulin sensitivity, and disposition indexes in the adult did not correlate with those at earlier ages. We conclude that glucose tolerance declines between the first month of life and early adulthood in the sheep, reflecting decreasing insulin sensitivity and absence of compensatory insulin secretion. Nevertheless, the capacity for insulin secretion in the adult reflects that early in life, suggesting that it is determined genetically or by persistent influences of the perinatal environment.
KW - Age
KW - Disposition index
KW - Secretion
KW - Sensitivity
KW - Sex characteristics
UR - http://www.scopus.com/inward/record.url?scp=2442693139&partnerID=8YFLogxK
U2 - 10.1152/ajpendo.00340.2003
DO - 10.1152/ajpendo.00340.2003
M3 - Article
C2 - 14761875
AN - SCOPUS:2442693139
SN - 0193-1849
VL - 286
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 6 49-6
ER -