Effects of lithium on bone resorption in cultured foetal rat long-bones.

Increased serum calcium has been observed in manic depressive patients treated with lithium (Li), and one of the mechanisms increasing serum calcium could be a sensitizing effect of Li on bone resorption. In a previous study, however, Li has been found slightly to inhibit PTH-stimulated resorption in cultured foetal rat long-bones. In this work, we extended the study of the effects of Li on bone resorption in culture when resorption of foetal rat long-bones was stimulated by factors other than PTH.

[Distribution and function of a new hormone: parathyroid hormone-related peptide (PTHrP)].

Several research groups have identified a "parathyroid hormone related peptide" (PTHrP) in tumors of patients presenting with the hypercalcemia of malignancy. The N-terminal domain of this peptide has a high degree of homology with that of the parathyroid hormone (PTH) and shares the PTH biological activities. PTHrP has later been identified in several foetal and adult normal tissues: for instance, it is expressed and secreted by foetal parathyroid glands, and it plays an important role in placental calcium transport; it is also expressed in the uterus of pregnant rats; there it could have a paracrine action on myometer relaxation.

Expression of mRNA of parathyroid hormone-related peptide in fetal bones of the rat.

Previous studies have indicated that 19-day-old fetal long bones of the rat contain an adenylyl cyclase-stimulating activity antigenically related to parathyroid hormone-related peptide. To ascertain its origin, Northern blotting and in situ hybridization histochemistry were performed. Results demonstrate that mRNA of parathyroid hormone-related peptide is present in RNA extracted from fetal long bones of the rat and that cells responsible for its production are localized in the periosteum.

[Persistent and recurrent hyperparathyroidism following parathyroidectomy].

In a series of 416 parathyroidectomies for primary or secondary hyperparathyroidism, 19 were reoperations for persistence (17 cases) on recurrence (2 cases) of the disease. (1) Preoperative localisation studies were useless in half of the cases. (2) In re-explorations, 72% only of parathyroid glands were discovered, 46% of them in ectopic locations.

Longitudinal study of bone metabolism after ethanol withdrawal in alcoholic patients.

The pathogenesis of osteopenia in chronic alcoholism remains unclear, and many ethanol-related abnormalities have been advocated to explain bone loss. A direct inhibitory effect of ethanol on osteoblast function was suggested by in vivo and in vitro studies. We measured biochemical markers of bone turnover in 12 alcoholic men before and during a 2 week period of alcohol withdrawal, and we compared the results with those obtained in 15 nonalcoholic men.