Changes In iPTH Research Articles

The effect of vitamin D on the sequential changes in serum calcium(Ca), phosphorus(P) and parathyroid hormone(iPTH) in the first weeks of life is unknown. Two groups of 6 2-3 day old pigs from 4 litters, raised in areas without ultraviolet light, were fed diet (Ca:P, 1.3:1) with (D) or without (-D) vitamin D. Weight, radiographic changes in the long bones and changes in Ca, P, iPTH and 25-hydroxyvitamin D (25-OH-D) were monitored weekly for 5 weeks and 2 weeks following treatment of the -D group with 1000 IU vitamin D3 daily. Weight gain at 7 weeks was the same in D and -D pigs (3.3 vs 2.9 × baseline). In -D pigs, radiographic changes of rickets were present at 3 weeks, clinical signs at 4 weeks. A pattern of decreasing values in Ca, P, and iPTH was observed in both groups to the 4th week. Thereafter, in D pigs, Ca and P returned to pre-diet values, and iPTH stabilized at values 50% lower. -D pigs showed greater changed+ chan D pigs (average mg/dl decrease from initial values): Ca at week 1 (1.05 vs .02); P at week 1 (2.43 vs .64), 2 (1.8 vs +.72), 3 (4.85 vs .98) and 4 (4.52 vs 1.18) and smaller decline in iPTH at week 4 (48 vs 65% of pre-diet values). Hypocalcemia, hypophosphatemia, and a two-fold increase in serum iPTH present in the -D group at 5 weeks were normalized after treatment; Ca remained slightly low. 25-OH-D, 78% lower than maternal values at the start of the study, was not less than 5 ng/ml regularly in -D pigs until the 4th week. In neonatal pigs, the decrease in serum phosphorus before change in iPTH is an early feature of vitamin D deficiency, suggesting a direct role of vitamin D in the physiologic hyper-phosphatemia in the very young. *p values range <.05 to <001.

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