Dixit V P
Acta Anat (Basel). 1976;95(2):182-9.
With the object of investigating the so called 'feedback' mechanism, whereby hormones from the various endocrine glands influence the hypothalamus in its regulation of the hypophysial tropic hormones, the activity of the nucleus preopticus (NPO) has been studied by means of karyometry under experimental conditions to understand the endocrine nature of the hypothalamic nuclei. (1) Oestrogen and testosterone propionate caused an increase in nuclear volume of the NPO cells, which is related to the synthesis of secretion. An increase of the nuclear volume is attributed to an increase of secretion. (2) Methylthiouracil (MTU) and thiourea bring about shrinkage in nuclear dimensions (p less than 0.001). Depletion of NSM is noticed in the hypothalamo-hypophysial neurosecretory system after MTU administration. (3) Two to five days' administration brings about depletion of NSM in the cells of the NPO. Eight to 15 days' metopiron treatment enhanced the activity of NPO cells. (4) Hypophysectomy caused shrinkage of the NPO cell nuclei, depletion of AF-stainable material in the cells of the NPO. ACTH treatment reversed these changes and brought about hypertrophy of the neurosecretory cells. (5) Neomercazole treatment and radiothyroidectomy bring about shrinkage in the NPO cell nuclei. Thyroidectomized toads when injected with thyroxine showed an enlargement of their nuclei.
为了研究所谓的“反馈”机制，即各种内分泌腺分泌的激素如何影响下丘脑对垂体促激素的调节，我们通过核测量法在实验条件下研究了视前核（NPO）的活性，以了解下丘脑核的内分泌性质。（1）雌激素和丙酸睾酮可导致NPO细胞的核体积增大，这与分泌合成有关。核体积的增加归因于分泌的增加。（2）甲基硫氧嘧啶（MTU）和硫脲可导致核尺寸缩小（p<0.001）。给予MTU后，下丘脑-垂体神经分泌系统中神经分泌物质（NSM）减少。（3）给药两到五天可导致NPO细胞中的NSM减少。美替拉酮治疗八到十五天可增强NPO细胞的活性。（4）垂体切除导致NPO细胞核缩小，NPO细胞中嗜酸性可染物质减少。促肾上腺皮质激素（ACTH）治疗可逆转这些变化，并使神经分泌细胞肥大。（5）新咪唑治疗和放射性甲状腺切除术可导致NPO细胞核缩小。给甲状腺切除的蟾蜍注射甲状腺素后，其细胞核会增大。
