Differential effects of short and long durations of insulin-induced maternal hypoglycemia upon fetal rat tissue growth and glucose utilization.
We studied the effects of short and long durations of insulin-induced maternal hypoglycemia upon in vivo glucose utilization of several fetal tissues in the rat. Osmotic minipumps filled with insulin were implanted in pregnant rats on d 15 or 18 of gestation (term 21.5 d), and radiolabeled 2-deoxyglucose was used to measure relative glucose utilization rates (rGU) of fetal liver, lung, muscle, kidney, heart, placenta, and brain on d 20 of gestation after 2 or 5 d of hypoglycemia. Maternal plasma glucose concentrations decreased within 24 h of pump placement and remained less than controls throughout gestation. Fetal plasma glucose and insulin concentrations on d 20 were equally reduced after 2 and 5 d of hypoglycemia. Both 2 and 5 d of hypoglycemia were associated with significant reductions in the rGU of fetal liver, lung, and muscle. Reductions in fetal kidney rGU also occurred after 2 and 5 d of hypoglycemia but to a smaller degree. rGU of fetal heart was reduced after 2 d of hypoglycemia, but was normal after 5 d of hypoglycemia. Both 2 and 5 d of hypoglycemia were associated with increased rGU of fetal brain. Five d, but not 2 d of hypoglycemia resulted in decreased fetal weight on d 20 of gestation. However, at term, newborn pups delivered of hypoglycemic mothers weighed significantly less than controls regardless of the timing of minipump placement. Liver, lung, and carcass of these growth-retarded pups weighed less than control tissues, whereas kidney, heart, and brain weights were not affected.(ABSTRACT TRUNCATED AT 250 WORDS)
Lueder
F L
FL
Department of Pediatrics, Northwestern University Medical School, Evanston Hospital, Illinois 60201.
Buroker
C A
CA
Kim
S B
SB
Flozak
A S
AS
Ogata
E S
ES
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003847:Deoxyglucose / Q000378:metabolism; D005314:Embryonic and Fetal Development; D005260:Female; D005317:Fetal Growth Retardation / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D005333:Fetus / Q000378:metabolism* / Q000473:pathology; D005947:Glucose / Q000378:metabolism*; D007003:Hypoglycemia / Q000139:chemically induced / Q000150:complications*; D007328:Insulin / Q000097:blood; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011248:Pregnancy Complications / Q000139:chemically induced; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D003847:Deoxyglucose; D005947:Glucose