GGTP is a membrane enzyme necessary in the transfer of some amino acids into the cytosol as a primary event in protein synthesis. Mechanisms of 1,25 D3 in promoting protein synthesis in corporal cells need further elucidation. Circulating leukocytes offer a readily accessible modality for assay of cellular enzyme activity. We, therefore, studied the effects of 1,25 D3 on growth and GGTP activity in young male Wistar rats. The animals were allowed ad libitum feeding of standard Purina Lab Chow during a period of 21 days. Vitamin D supplemented animals received daily injections of 50 pMol 1,25 D3 in 0.2 ml polyethylene glycol(PEG). Control animals were injected with 0.2 ml PEG alone. At sacrifice, leukocyte GGTP was assayed. Growth parameters and enzyme activity are shown below: (Mean± S.D.; *Indicates Difference p <0.05)
A tenfold increase in GGTP activity was noted in 1,25 D3 supplemented animals. Our study suggests an induction of GGTP activity in leukocytes by 1,25 D3 which may, in turn, influence corporal protein synthesis.