Hypomagnesemia due to Renal Magnesium Wastage of Unknown Etiology

A twenty-two year old woman, investigated because of tetanic convulsion and refractory hypocalcemia, was shown to have hypomagnesemia, hypokalemia, hypocalciuria and hypophosphaturia. The patient sometimes had loose stool but no steatorrhea. Bowel absorption test of D-Xylose, 131I-triolein and 47Ca were in the normal range. Relative hypermagnesuria was observed despite of hypomagnesemia. Renal function was normal. Parathyroid hormone level was quite low but showed a rapid increase after the injection of magnesium supplement. Normal responsiveness to parathyroid hormone was observed in the kidney. Oral administration of magnesium supplement resulted in relief of subjective symptoms as well as normal serum levels of calcium and potassium. During this period, serum magnesium rose up but never reached the normal level. These findings suggested that renal magnesium wastage of unknown etiology was the significant factor contributing to the hypomagnesemia and that hypocalcemia was probable due to impaired serection of PTH. The mechanism of the hypokalemia observed with the magnesium depletion remains unknown

Response of Serum Prolactin to Thermal Stress During Water Immersion

Physiological action of prolactin is not well-known in human except those concerning pregnancy and lactation. Elevated serum prolactin level due to various stresses such as heat load, physical exercise, surgery, gastroscopy has been reported. In order to elucidate the response of serum prolactin to thermal stress, preliminary experiments were done in a male subject. Three different thermal stimuli were applied by head-out water immersion (water temperature: 28.5, 34 and 40℃, respectively) for 30 or 60min. Decrease of 1.5℃ in oral temperature and 48% decrease of serum prolactin concentration compared to basel level were induced by 28.5℃ water immersion. Decrease of 0.6℃ in oral temperature and almost stable prolactin level were observed during 34℃　water immersion. By 40℃ water immersion, 2.1℃ increase in oral temperature and 578% increase of prolactin level were induced. And in every experiment, prolactin level returned to control level (5-13ng/ml) 24 hours after cessation of thermal stimuli. Highly significant correlation of mean body temperature with serum prolactin level was observed at the different thermal stimuli. The present results indicate the thermo-dependent regulatory mechanism of prolactin release in human

Effect of Thyroid Hormone on Thermal Sweating

Hyperhidrosis with hyperthyroidism and dry skin with hypothyroidism are clinically well-known phenomenon, however, up to now there is no general agreement concerning the effect of thyroid hormone on thermal sweating based on the objectifve quantitative data. In the present study thermal sweating responses in the patients suffering from hyperthyroidism and hypothyroidism were examined by means of capacitance hygrometer-sweat capture capsule method which can determine much finer fluctuation of sweat rate. In environmental control chamber (25℃, 60% rh) local heat load (43℃ water bath, 30 min) was applied on the lower legs to induce thermal sweating. Sweat-onset time after heat load in hyperthyroidism (n=5) and control group (n=9) were 10.6±5.2 and 15.6±5.0 min (Mean±SD), respectively. Total sweat volume induced by 30 min heat load in both group were 66.06±26.24 and 47.95±31.25 mg/capsule, respectively. Increase of oral temperature at sweat-onset time in both group were 0.20±0.16 and 0.10±0.08℃, respectively. In the two patients suffering from hypothyroidism more than a few years no sweat was observed during 30 min heat load. In one case sweat-onset time was 56 min where 0.50℃ rise in oral temperature, and in the other case no sweat was induced finally even though 0.90℃ increase in oral temperature during 51 min heat load. In contrast remarkably short sweat-onset time and large amount of sweat were observed in the two thyroidectomized patients who stopped replacement therapy of triiodothyronine (T3) two weeks ago, although, whose thyroid function (T3, T4, FT4 and TSH) were revealed the same as the value of long-term hypothyroidism group. From the present results, following two suggestions can be drawn; one is thyroid hormone enhances thermal sweating, the others is thyroid hormone action at the intra-cellular level might be changed relatively slow compared to the regulation of thyroid hormone concentration in serum level. Further researches are necessary to clarify the effect of thyroid hormone on thermal sweating and the action site of thyroid hormone on sweating mechanism