Alopecia and mood stabilizers: two case reports.

Two cases of alopecia observed during treatment with lithium and valproate are described, and the recent literature on this subject is reviewed. Our clinical observations confirm earlier reports. These toxic alopecias are characterized by a diffuse but rarely total hair loss. After stopping medication, the hair grows back generally and completely. Two cases of toxic alopecia are presented where hair grew back following a substitution of lithium by valproate in the first case and after stopping valproate in the second. The evaluation and therapeutic attitude in the presence of alopecia in patients needing mood stabilizers are also discussed.

Effect of diphosphonates on adenosine 3':5'-cyclic monophosphate in mouse calvaria after stimulation by parathyroid hormone in vitro.

1. The diphosphonates, disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) and disodium dichloromethylene diphosphonate (Cl2MDP), inhibit bone resorption in animals and in explanted bone in tissue culture. The possibility that these effects might be due to inhibition of skeletal adenylate cyclase has been studied. 2. EHDP and Cl2MDP, added for 30 min to the incubation medium at concentrations known to inhibit bone resorption, had no effect on basal content of adenosine 3':5'-cyclic monophosphate (cyclic AMP) of mouse calvaria incubated in vitro, nor did they inhibit the rise in cyclic AMP induced by bovine parathyroid hormone. 3. Pretreatment of mice for 3 days with Cl2MDP also had no effect on cyclic AMP under basal conditions or after incubation of explanted calvaria with parathyroid hormone in vitro. EHDP under similar conditions slightly inhibited the increase induced by parathyroid hormone but had no effect on basal concentrations of cyclic AMP. 4. It is suggested that the inhibition of adenylate cyclase is not an essential feature of the reduction of bone resorption by diphosphonates, which may act by direct inhibitory effects on the dissolution of hydroxyapatite and perhaps by other unidentified effects on bone cells. Key words: adenosine 3':5'-cyclic monophosphate, bone, dichloromethylene diphosphonate, diphosphonates, ethane-1-hydroxy-1,1-diphosphonate, parathyroid hormone.

Secretion of inorganic phosphate in the rat nephron.

1. The existence of tubular secretion of inorganic phosphate (Pi) in the mammalian kidney has been investigated by studying the renal response of rats infused with sodium phosphate by three different techniques. 2. Clearance studies indicate that, in anaesthetized rats, the net tubular reabsorption decreases markedly in response to Pi infusion. In conscious rats, the clearance of Pi slightly exceeded that of inulin at high plasma Pi concentration. 3. Free-flow micropuncture in control rats showed a net tubular reabsorption of Pi along the proximal tubule, and probably between the end of the distal tubule and the ureteral urine. In phosphate-loaded rats, whether receiving parathyroid hormone or not, an apparent net secretion of Pi was observed between the end of the distal tubule and the reteral urine. In the phosphate-loaded group receiving parthyroid hormone, net secretion was also observed very early in the proximal tubule followed by a predominant reabsorption along this segment. Thus the early proximal tubule and probably also the terminal nephron can be the site of either net reabsorption or net secretion. 4. Microperfusions of proximal tubules show a fall in the specific radioactivity of the perfused radioactive Pi solution, indicating entry of Pi into the lumen.