Effect of glycemic control on calcium and phosphorus handling and parathyroid hormone level in patients with non-insulin-dependent diabetes mellitus.

The present study was undertaken to determine whether improvement of hyperglycemia alters calcium and phosphorus handling, parathyroid hormone (PTH) secretion and bone turnover in patients with non-insulin-dependent diabetes mellitus (NIDDM). We measured serum and urinary mineral levels, serum intact PTH and osteocalcin on admission and at discharge (38 +/- 3 days later, Means +/- SEM) in 28 patients with poorly-controlled NIDDM (63 +/- 2 years old, 13 males and 15 females). During the hospitalization period, glycemic control was markedly improved. Serum calcium levels remained unchanged, but serum phosphorus increased. Urinary calcium and phosphorus excretion decreased. Serum intact PTH decreased from mid-normal (30.0 +/- 2.2 ng/l) to low normal values (24.0 +/- 1.3 ng/l) (P < 0.01, normal values: 10-65 ng/l). Serum osteocalcin increased from 4.14 +/- 0.35 to 4.92 +/- 0.40 micrograms/l (P < 0.01, normal values: 2.5-13 micrograms/l). On admission, urinary calcium and phosphorus excretion showed a positive correlation with urinary glucose excretion. Serum calcium levels showed a negative correlation with serum intact PTH (r = -0.46, P < 0.05). Moreover, the change in serum calcium during the hospitalization was negatively correlated to the change in serum intact-PTH (r = -0.45, P < 0.05). Serum phosphorus concentrations showed a positive correlation with the renal threshold for phosphorus excretion on admission (r = 0.86, P < 0.01). These results indicate that hyperglycemia causes excess urinary calcium and phosphorus excretion in patients with NIDDM. In response to urinary calcium loss, PTH secretion is mildly stimulated. Bone formation seems to be suppressed in the hyperglycemic state in spite of increased PTH secretion.

Molecular characteristics of porcine thymus histone H1 variants.

We constructed an assay system to measure the annealing activity that is one of the functional features of nuclear proteins, using ssDNAs derived from M13 phage recombinants which contained a complementary 406-bp portion each. Histone H1 variants were purified from porcine thymus by separation of chromatin, extraction with 5% perchloric acid, and reversed-phase HPLC. Three types of histone H1 variants were found by analysis of amino acid composition and on SDS-PAGE. All of these could promote the annealing. According to Hill's analysis all had similar numbers of binding sites to DNA strands but dissociation constants and annealing activity were different. The number of binding sites, dissociation constants, and annealing activity were changed by dephosphorylation of histone H1 variants. This result suggests that histone H1 variants have different affinities for DNA molecules and ssDNA-annealing activity, which is regulated by phosphorylation.

Effect of glycyrrhizine on hyperkalemia due to hyporeninemic hypoaldosteronism in diabetes mellitus.

Liquorice extract has been claimed to induce inhibition of the activity of 11 beta-hydroxysteroid dehydrogenase which converts cortisol to cortisone. This enzyme is thought to protect the mineralocorticoid receptor from being occupied by endogeneous glucocorticoids in the kidney. Based on these hypotheses, we investigated the effect of low-dose glycyrrhizine on hyperkalemia due to hyporeninemic hypoaldosteronism in eight subjects with NIDDM. The mean serum potassium concentration decreased from 5.3 +/- 0.3 (SD) mEq/1 to 4.9 +/- 0.2 mEq/1 when 15 g of calcium polystyrene sulfonate, a potassium-binding resin, was given per day, and it decreased significantly to 4.4 +/- 0.4 mEq/1 with 150 mg/day of glycyrrhizine therapy. Changes in fasting plasma glucose and hemoglobin A1c were not significant. These data support the assumption that liquorice extract can be used safely in the therapy for treating hyperkalemia due to selective hypoaldosteronism in diabetes mellitus subjects.

Calcium and vitamin D metabolism in Guamanian Chamorros with amyotrophic lateral sclerosis and parkinsonism-dementia.

We evaluated 16 Guamanian Chamorros with amyotrophic lateral sclerosis and 33 patients with parkinsonism-dementia for disturbances of calcium and vitamin D metabolism. The serum immunoreactive parathyroid hormone level was mildly elevated in 6 patients with amyotrophic lateral sclerosis and in 5 patients with parkinsonism-dementia. There were significant positive correlations between serum immunoreactive parathyroid levels and duration of illness in male patients with motor neuron disease, but not in female patients or in patients with parkinsonism-dementia. Intestinal absorption of calcium, as assessed by serum and urinary activity of calcium 47 following oral administration, was decreased in 2 patients with amyotrophic lateral sclerosis and in 4 patients with parkinsonism-dementia, all of whom had low levels of serum 1,25-dihydroxyvitamin D. Reductions in cortical bone mass were striking in patients with motor neuron disease. A significant negative correlation was found between the percentage of cortical area of the second metacarpal bone and muscle atrophy and weakness, and significant positive correlations were found between degree of immobility and ratio of urinary hydroxyproline to creatinine in patients with amyotrophic lateral sclerosis and parkinsonism-dementia. In general, abnormalities in calcium metabolism were subtle. Thus, if the demonstrated deposition of metals, particularly calcium and aluminum, in central nervous system tissues of Guamanians with these two conditions is a cause of the diseases and of the early appearance of neurofibrillary tangles in neurons, the accumulation has apparently occurred long before onset of symptoms, and detectable abnormalities of calcium and vitamin D metabolism may already have been corrected.