[Effect of 1 alpha, 25-dihydroxy vitamin D3 on renal growth in rat]

It has been demonstrated that 1,25 dihydroxy vitamin D3 [1,25 (OH)2D3] can control the growth of various cells in vitro. Despite the data obtained so far, is not known whether or not 1,25 (OH)2D3 can modulate renal growth. To determine the effect of 1,25(OH)2D3 on renal growth, 80 pmol of 1,25(OH)2D3 was administered intraperitoneally for one week consecutively to weanling Sprague-Dawley rats using a minipump under the condition of strict pair-feeding. Kidney wet weight/body weight, renal protein/DNA ratio increased significantly, but renal RNA/DNA and DNA content were not affected. It was concluded that 1,25(OH)2D3 did promote renal growth in weaning rats, in contrast to the inhibitory effect of 1,25(OH)2D3 on renal cell proliferation as previously reported from earlier in vitro studies. Based on the evidence of an increased protein/DNA ratio, and unchanged RNA/DNA ratio and DNA content, renal growth seemed to have been the result of renal hypertrophy enhanced by 1,25(OH)2D3.