SummaryTo study the adequate intake (AI) for vitamin D in the elderly, we have performed an intervention study with 800 IU/d of vitamin D 3 in the institutionalized elderly. Sixty-two institutionalized elderly were randomly assigned to two groups; receiving either supplements of 200 mg calcium plus 800 IU vitamin .3 ng/mL in the Ca ϩ VD group and to 11.1 ng/mL in the Ca group. Post intervention serum 25OH-D level was significantly higher in the Ca ϩ VD group than in the Ca group ( p Ͻ 0.001). In 53 subjects (85.5%) who took more than 80% of their supplements for 30 d, serum PTH level in the Ca ϩ VD group was significantly lower than in the Ca groups ( p ϭ 0.05). Bone turnover markers were not significantly changed after intervention in either group. Daily supplementation of 800 IU vitamin D 3 was considered effective in the institutionalized elderly with minimal chance of sun exposure, but further studies with longer duration are necessary.

SynopsisIn order to investigate the sequence of events concerning gonadotropin surge, serum LH, FSH and estradiol concentrations were measured during the rat estrous cycle as well as hypothalamic and blood levels of LH-RH in the preovulatory stage. Normally cyclic female Wistar rats kept on 12 hr light (from 22.00 hr to 10.00 hr) and 12 hr dark were killed at different times of day during each stage of the cycle. The hypothalamus was quickly dissected out, divided into 3 portions (the anterior, middle and posterior) and extracted in 90% methanol.Blood LH-RH was extracted by affinity chromatography prior to radioimmunoassay.The content of LH-RH in the anterior and middle hypothalamus started to decrease between 1.00hr-3.00hr, reached its nadir at 6.00hr on proestrus and recovered to its previous values on estrus. Almost simultaneously blood LH-RH concentration showed an increase of 18.3 pg/ml-8.8 pg/ml between 1.00hr-3.00hr, and then fell to<1.0pg/ml at 6.00 hr. On the other hand, serum estradiol level began to elevate on diestrus II followed by its peak at 6.00hr on proestrus, while the peaks of serum LH and FSH were observed at 8.00 hr and 10.00hr, respectively.These studies indicate that the elevation of serum estradiol was followed by the release of LH-RH from the hypothalamus and the LH-RH may be responsible for the preovulatory discharge of gonadotropin.

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