In a prospective, controlled, and randomized clinical trial, we examined the effects of treatment with vitamin D (1,000 IU/d), calcium (1 g/d), and ethane-1-hydroxy-1,1-diphosphonate (EHDP; 7.5 mg/kg body weight) on vertebral bone mass in fourteen asthmatics undergoing long-term treatment with systemically applied corticosteroids. The extent of steroid-induced bone loss was judged by vertebral bone density of the lumbar spine measured by dual-photon absorptiometry as well as by vertebral crush fracture incidence examined by conventional X-ray. Results of the measurements before treatment and after six mo were compared with those of an untreated control group of nineteen asthmatics. Bone density increased during the observation period by 5% in the treated group, compared with a decrease of 4.3% in the untreated control group (p < 0.01). Moreover, in the treated group no radiologically visible new fractures occurred; in the control group new fractures were observed in four patients. There were no serious side effects of the applied drugs during the 6-mo period. Therefore, the combination of EHDP, calcium, and vitamin D appears to be a useful regimen for the management of steroid-induced bone loss in adult asthmatics.

Objectives-Osteocalcin is the major non-coliagenous protein of bone and is regarded as a specific index of bone formation. The aim of this study was to examine the rate of bone formation measured by osteocalcin in 38 patients with ankylosing spondylitis (AS) and its dependence on various parameters of calcium and phosphate metabolism. Methods-Serum osteocalcin, alkaline phosphatase, parathyroid hormone, and 1,25-dihydroxyvitamin D were measured in 38 patients with ankylosing spondylitis and in 52 controls. Results-Mean serum osteocalcin was significantly reduced in patients with AS (men 1*7 (1.1) ng/ml; women 1-2 (1.1) ng/ml) compared with the corresponding control groups (men 3-2 (1.3) ng/ml; women 4-1 (1.7) nglml). Although they have been useful in measuring bone turnover, they also have significant limitations.7 8 y-Carboxyglutamic acid containing protein of bone, the most abundant protein of bone derived from osteoblasts,9 is a specific marker of bone formation. The synthesis of this protein, usually called osteocalcin, is regulated by calciotropic hormones.'01 In particular, 1,25-dihydroxyvitamin D stimulates the production of osteocalcin in osteoblasts.'0 The aim of this study was to examine the rate of bone formation (measured by the amount of osteocalcin) in patients with AS and its dependence on various parameters of calcium phosphate metabolism, especially parathyroid hormone and 1 ,25-dihydroxyvitamin D. Patients and methodsThe study group consisted of an unselected group of 38 consecutive patients with mild to moderate AS (13 women and 25 men, mean ages 37 and 42 years respectively) attending an outpatient clinic for rheumatic disease. The control group (23 women and 29 men aged between 20 and 64 with a mean (SD) age of 37 (14.6) and 41-6 (17) years respectively) had no evidence of calcium or skeletal abnormalities by routine history, physical, and biochemical evaluation. Patients with AS had characteristic physical signs and radiographic features according to New York clinical criteria.'2 None of the patients received glucocorticoids and only two received non-steroidal anti-inflammatory drugs (NSAIDs).For all subjects and patients blood samples were collected in the morning (8 am) after an overnight fast. Serum samples were separated by centrifugation and then frozen at -40'C.Osteocalcin was measured in duplicate by a commercial radioimmunoassay (ImmunoNuclear Corporation, Stillwater, MN, USA) by the method of Price and Nishimoto using purified calf bone GLA protein.'3 The sensitivity of the assay was 0-2 ng/ml and the concentration could be determined in all patients. In all cases the intraassay variation was less than 8% and the interassay variation was less than 12%. Parathyroid hormone was determined by a commercial radioimmunoassay (Fleurus, Belgium) using chicken antibody raised against human parathyroid hormone (c terminal). The interassay variation was less than 13%. 25-Hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D were determined as described elsewhere. '4

Abstract. The conversion of [1,2,6,7-3H]testosterone2 to [3H]dihydrotestosterone has been assessed in ground spongiosa of normal and osteoporotic bone. The tissue was obtained from 23 patients, 18 women, 3 men and 2 children who were undergoing orthopedic surgery. The formation of dihydrotestosterone was demonstrated in all samples examined. The half maximum rate of dihydrotestosterone formation occurred at a substrate concentration of 0.3 μm a value similar to that reported for dihydrotestosterone formation in other androgen target organs. Under the standardized conditions utilized in this study the rate of dihydrotestosterone formation did not differ significantly in normal as compared to osteoporotic bone. Furthermore, the conversion of testosterone to androstenedione was also similar in osteoporotic and normal bone. Based on these studies it seems reasonable to conclude that dihydrotestosterone rather than testosterone is the active intracellular androgen in human bone since in other androgen target tissues androgen action is mediated by dihydrotestosterone if 5α-reductase is present.

Abstract. Calcium metabolism and plasma concentrations of vitamin D metabolites were investigated in 27 children on long-term anticonvulsant therapy. Serum calcium was in the low normal range, phosphorus was normal, parathyroid hormone concentrations and alkaline phosphatase were elevated. Plasma 25-hydroxyvitamin D (25-OH D) and 24,25-dihydroxyvitamin D (24,25-(OH)2D) were decreased, but 1,25-dihydroxyvitamin D (1,25-(OH)2D) was normal when compared with a synchronous control group. The serum concentrations of all anticonvulsant drugs given were measured. The decreases in 25-OH D and 24,25-(OH)2D did not depend on the blood level of a single drug, or any combination of drugs given, or on the duration of therapy. The 25-OH D levels were negatively correlated with the number of different drugs used, which may reflect the severity of the neurologic disorder, and therefore with non-specific factors such as exposure to sunlight, nutrition, or physical activity.Our data do not support the hypothesis that anticonvulsant drugs act on vitamin D metabolism. Key words: Calcium metabolism -Vitamin D metabolites - Anticonvulsant drugsAnticonvulsant drugs, particularly diphenylhydantoin (DPH) and phenobarbital (PB), are known to affect calcium metabolism and to cause rickets or osteomalacia [1,2]. In vitro, in the rat, Caspary [3] and Koch et al. [4] found that intestinal absorption of calcium was depressed by DPH but not by PB. The amounts of the vitamin D dependent calcium binding were found to be normal [3].Since PB induces hepatic microsomal enzymes, it has been suggested that due to increased 25-hydroxylase activity PB may increase the availability of25-OH D and its conversion to more polar but less active vitamin D metabolites, thus enhancing plasma clearance of vitamin D and leading to reduced serum and tissue levels of active vitamin D metabolites [5][6][7]. Conversely, in patients receiving anticonvulsant therapy plasma levels of 24,25-(OH)2D were decreased [8], and levels of 1,25-(OH)2D were reported to be normal [9]. It was concluded that in the presence of PB the intestine is less responsive to 1,25-(OH)2D, or that other factors than vitamin D metabolites may impair intestinal calcium transport. [10] found that in epileptic patients on anticonvulsant therapy absorption of calcium from the digestive tract was moderately depressed but that small doses of 1,25-(OH)2D as well as 25-OH D enhanced calcium absorption. They concluded that the sensitivity of the intestine to vitamin D was not impaired in these subjects. These results may indicate that in patients on anticonvulsant therapy the serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone (PTH) abnormalities are not caused by a defect in 1,25-(OH)2D metabolism or action on the intestine. As vitamin D metabolism is particularly influenced by external factors such as seasonal changes and differences in exposure to sunlight, physical activity and nutritional status, control data may be derived only from carefully matched subjects. This was also cons...

In contrast to prevention, the therapy of manifest osteoporosis remains a clinically significant problem. So far all therapeutic attempts have yielded unsatisfying results. For this reason we have tried to achieve a positive bone balance by sequential stimulation and inhibition of the osseous metabolism. The therapy consisted of six 14-day courses with 400 units (1-38)hPTH per day and, in addition, starting with the 2nd week of PTH therapy, EHDP 5 mg per kg body weight per day for a total of 2 weeks. Already the initial therapeutic course resulted in a stimulation of decreased bone metabolism which could be documented by an increase in the calcium-47 accretion rate (six patients). An increase of the alkaline phosphatase could be noted (four patients); this, however, did not correlate with the calcium accretion. A positive calcium balance could, nonetheless, only be attained in four of eight patients within this period, while neither the alkaline phosphatase nor the kinetics would allow a prediction of this effect. Changes of the balance coincided with equal changes in the net calcium absorption. The urinary calcium excretion increased temporarily during the therapeutic phase. We were not able to detect an influence on the vitamin D metabolites. Histomorphometric studies did not demonstrate an increase in bone mass in the iliac creast after six therapeutic courses. Nevertheless, progressive deformations of vertebral bodies did not occur. We conclude that already after 2 weeks this therapeutic concept can lead to a stimulation of bone metabolism.

Skeletal demineralization occurs in thyrotoxicosis. Fecal calcium excretion may be enhanced, and calcium balance tends to be negative. We investigated intestinal calcium transport in 12 hyperthyroid patients. Absorption was measured by segmental perfusion in the proximal jejunum at calcium concentrations commensurate with those in the fasting and postprandial states. At low luminal concentrations, under conditions where calcium is transported predominantly by active processes, the calcium absorption rate was reduced though not abolished in hyperthyroid patients (16 +/- 4 (SE) mumol/h . 30 cm segment) as compared to normal subjects (71 +/- 8 mumol/h; P less than 0.001). When perfusate calcium was raised to 5 mmol/liter there was little increment of the net absorption rate in the hyperthyroid group (45 +/- 11 mumol/h), whereas that in the normal subjects rose to 183 +/- 17 mumol/h. Likewise, the unidirectional calcium flux out of the lumen was low in hyperthyroidism (43 +/- 7 mumol/h), suggesting that low net absorption rates were not due to transmucosal calcium loss. D-Xylose permeation was similar in all study groups. Treatment of the thyroid disease led to a marked increase in calcium absorption rates from 33 +/- 10 to 124 +/- 20 mumol/h (at 2 mmol/liter P less than 0.001; n = 5) into the range of values in normal subjects (124 +/- 9 mumol/h). Circulating levels of 1,25-dihydroxyvitamin D were low in hyperthyroid patients (38 +/- 11 pg/ml) and increased during treatment to 63 +/- 11 pg/ml (P less than 0.025; n = 9), whereas 25-hydroxyvitamin D was normal and remained unchanged. We conclude that intestinal calcium transport, particularly its active component, is reversibly decreased in hyperthyroidism. The association with low plasma levels of the active vitamin D metabolite suggests that the decrease in calcium absorption may be related to calcium-regulating mechanisms as a consequence of the net calcium efflux from bone in this disease.

Summary. The effects of Ca 2+ and calcitonin infusions on circulating glucagon, glucose, C-peptide, Ca 2+, and calcitonin were investigated in hyperglucagonaemic insulin-dependent diabetics. In 14 insulin-deprived diabetics and 12 healthy volunteers 2 h infusions of saline (0.154 tool/l), Ca 2+ (0.375 mmol/kg body weight), and ealcitonin (4.5 IU/kg body weight) were performed. There were no significant changes during saline infusion. In the diabetics, Ca 2+ infusions induced a rise of plasma Ca 2+ up to 3.2 _ 0.1 mmol/1 and a fall of circulating glucagon (--26.4 +_ 5.7%; p < 0.001) and glucose (-23.3 _+ 3.6%; p < 0.05). Plasma calcitonin rose to twice basal values (p < 0.025). During calcitonin infusions plasma Ca 2+ decreased slightly to 2.1 + 0.2 mmol/1; a fall was found in both glucose (-24.4 _+ 4.0%; p < 0.05) and circulating glucagon (-22.5 +_ 4.3%; p < 0.001), Two groups of 6 healthy volunteers were subjected to saline and Ca 2+, or to Ca 2+ and calcitonin infusions. Both Ca 2+ and calcitonin infusions induced a fall of serum insulin (-30.1 + 6.6%; p < 0.05). Calcitonin depressed circulating glucagon by -18.6 +_ 4.4% (p < 0.025), whereas during Ca 2+ infusions glucagon decreased only by -6,5 _+ 1.9% (p > 0.1). We conclude from our results that an increase of circulating calcitonin induced by Ca 2+ infusions or by exogenous calcitonin administration appears to depress elevated circulating glucagon and glucose in insulin-dependent diabetics.

Neuropeptide Y (NPY) regulation of intracellular cyclic AMP accumulation was studied in human E~ving's sarcoma cell line, WE-68. NPY inhibited vasoactive intestinal peptide (VIP)-and dopamine-stimulated but not basal cyclic AMP formation. The peptide effect was rapid (< 2 rain), concentration-dependent with a half-maximal effective concentration (ECso) of 8 nM NPY, and maximal inhibition reaching 60-70% with 100 nM NPY. Prior exposure of WE-68 cells to pertussis toxin completely abolished the inhibitory action of NPY. It is concluded that NPY attenuates agonist-stimulated cyclic AMP formation in Ewing's sarcoma WE-68 cells, and may do so via the inhibitory guanine nucleotide regulatory protein of adenylate cyclase.