Osteoporosis and parathyroid glands. I. The effect of prolonged calcium deficiency on the parathyroids of the adult rat
Sevastikoglou, J.A.; Larsson, S.E.
Clinical Orthopaedics and Related Research 85: 163-170
1972
ISSN/ISBN: 0009-921X PMID: 5036919 Document Number: 46853
1. Adult male Sprague-Dawley rats, 1 year old and weighing about 500 g, were given a proprietary low-Ca diet, Ca 0.09 and P 0.55%, with adequate vitamin D. Daily Ca intake was from 18 to 20 mg. There were 95 in all, in groups of 5, and controls were 10 rats on a normal laboratory diet with Ca 1.0 and P 0.75%. Surviving controls, 8, continued for 12 months; the experimental groups were killed first at weekly intervals to 5 weeks, then at 2-weekly intervals from 8 to 16 weeks, and the rest after from 6 to 10 and 12 months. After death parathyroid volume was computed from microscope sections of known thickness, measured by planimeter; cell nuclei were counted. Serum Ca had been recorded in other studies by Larsson (Acta Orthopaedica Scandinavica (1969) No. 120, Supplement) and the values recorded there were matched against parathyroid values and cell nuclei "hits". The 3 sets of data are tabulated and are discussed with observations on skeletal changes with development of osteoporosis described in the series referred to above. Serum Ca fluctuated with parathyroid volume without any great departure from the normal. Parathyroid volume in mm3 was: normal 0.35; experimental at 1 week 0.42, at 3 weeks 0.24; thereafter it rose to a maximum of 0.90 at 7 months and was 0.62 in the last group at 12 months. Corresponding values for serum Ca were in m-equiv/litre: normal 5.0; experimental 4.5, 4.7, 4.3 and 4.9. That is to say serum Ca was maintained slightly below normal at the expense of bone mineral.