Mortensen B, Gordeladze J O, Haug E, Schjerven L, Gautvik K M
Institute for Surgical Research, National Hospital, Rikshospitalet, Oslo, Norway.
Pharmacol Toxicol. 1993 Mar;72(3):188-93. doi: 10.1111/j.1600-0773.1993.tb00314.x.
Previous studies (Haug & Gautvik 1985) have demonstrated specific receptors for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in a clonal (GH3) strain of rat pituitary tumour cells. It was discovered that 1,25(OH)2D3 affected the production of prolactin and growth hormone in these cells in a calcium dependent manner. These findings were the basis for a hypothesis that vitamin D3 could be involved in the regulation of pituitary hormones in vivo. To further investigate this contention, female rats were given subcutaneous injections of 1,25(OH)2D3, 25-hydroxyvitamin D3 (25(OH)D3) or 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) three times a week for up to 12 weeks. Blood samples were withdrawn after 28, 56 and 84 days of treatment and analysed for vitamin D3 metabolites, prolactin and growth hormone, and serum ionized (free) and total calcium (Ca). Between treatment group comparisons of serum prolactin and growth hormone levels did not show significant vitamin D3 induced alterations. However, correlation matrix analyses on all variables revealed that serum level of growth hormone was significantly (P < 0.05) and inversely related to corresponding total Ca. Prolactin, on the other hand, may be subject to a complex regulation by 1,25(OH)2D3 and free Ca2+.
先前的研究（豪格和高特维克，1985年）已证实在大鼠垂体肿瘤细胞的克隆株（GH3）中存在1,25 - 二羟基维生素D3（1,25(OH)2D3）的特异性受体。研究发现，1,25(OH)2D3以钙依赖的方式影响这些细胞中催乳素和生长激素的产生。这些发现构成了一个假说的基础，即维生素D3可能参与体内垂体激素的调节。为了进一步研究这一论点，给雌性大鼠每周皮下注射1,25(OH)2D3、25 - 羟基维生素D3（25(OH)D3）或24,25 - 二羟基维生素D3（24,25(OH)2D3）三次，持续12周。在治疗28、56和84天后采集血样，分析维生素D3代谢产物、催乳素和生长激素，以及血清离子化（游离）钙和总钙（Ca）。治疗组之间血清催乳素和生长激素水平的比较未显示维生素D3诱导的显著变化。然而，对所有变量的相关矩阵分析表明，生长激素的血清水平与相应的总钙显著负相关（P < 0.05）。另一方面，催乳素可能受到1,25(OH)2D3和游离Ca2+的复杂调节。
