Abstract:

The evidence of dwarfism-like manifestation of rat was found by administration of hypodermic MSG 0.4 g/kg to the new born one every other day within 10 days after birth.We observed the rat bone development on the 11th day(new born stage),52th day(puberty)and 100th day(adult).The result showed that the trunk Jength of long bones of upper limb and lower limb,the thickness of tibia epiphysis and its multiplication area revealed signeficantly the development delay in the experimental groups P<0.05 for puberty groups,P<0.01 for the adule groups.For the 11th day groups,the length of long bone was on difference,but the thickness of epiphysis multiplication area,which determined the bone growth rate,decreased obviously.We could not discover the difference on the histologicalstructure of epiphysis and the development course of bone between experimental group and control group.The weight of pituitary gland in the experimetal groups possess of 55.6%(11th day group),42.4 %(52th day group)and 47.7 %(100th day group)of control groups. The immunohistochemical result indicated the number of GH-secreting cell was decreased.Cell volume was smaller.The body length and weight of the rats experimental groups were below 2S of control group.According to our results,the MSG could induce the rat dwasfism with GH deficiency.

Key words: monosodium glutamate, bone development, dwarfism