EFFECT OF HYPOINSULINEMIA ON GROWTH IN THE FETAL RABBIT

Insulin is an important regulatory hormone in the control of fetal gro wth. In a fetal rabbit model, a non-ruminant species, the effects of i nsulin deprivation on glucose, growth and protein metabolism were stud ied. The fetuses of IO pregnant New Zealand white rabbits in one uteri ne horn received a subcutaneous injection on day 25 of gestation (term = 30 days) of 0.1 mg streptozotocin (STZ)/gm fetal weight. The fetuse s in the opposite horn received a sham injection of buffer. The dams w ere then killed on day 29. The fetal insulin concentration was depress ed by 38%, and the serum glucose concentration was elevated by 28% in animals given STZ when compared to control animals. Fetal weights, car cass weights and skeletal growth, as measured by crown-rump length and tibial length of STZ-treated fetuses, were significantly reduced by 7 -13%. However, organ weights were not significantly different, except for the kidneys which were 17% lighter. Protein and mineral contents o f the carcasses were also reduced compared to the control fetuses. Thu s, insulin deprivation in fetal rabbits results in significant growth impairment in a pattern similar to that of human asymmetric intrauteri ne growth retardation.