「基礎醫學-生理學」內分泌腺體

激素(hormone)

藉由專一性接受器調節標的細胞功能,例如: 
Hormones regulate target cell function by binding to specific receptors. For example: 
1. 胰島素與胰島素受體結合後,可以促進細胞對葡萄糖的攝取和利用,從而降低血糖水平。 Insulin binds to insulin receptors to promote glucose uptake and utilization by cells, thereby lowering blood sugar levels. 
2. 甲狀腺素與甲狀腺激素受體結合後,可以促進細胞的氧化代謝,從而提高新陳代謝。 Thyroid hormone binds to thyroid hormone receptors to promote cellular oxidative metabolism, thereby increasing metabolism. 
3. 生長激素與生長激素受體結合後,可以促進細胞的生長和分化。 Growth hormone binds to growth hormone receptors to promote cellular growth and differentiation. 
4. 促性腺激素與促性腺激素受體結合後,可以促進性腺的生長和分泌性激素。 Gonadotropins bind to gonadotropin receptors to promote the growth and secretion of sex hormones by the gonads.

人類胚胎時期性激素(sex hormone)的分泌量與青春期前(prepuberty)相比胚胎時期較高,尤其是在妊娠早期。
In the human embryo, the secretion of sex hormones is higher than in prepuberty, especially in early pregnancy.
在妊娠第8周,胎兒的血液中睪丸酮(testosterone)的濃度是成年男性的100倍。
In the 8th week of pregnancy, the concentration of testosterone in the fetal blood is 100 times that of an adult male.
在妊娠第12周,胎兒的血液中雌激素(estrogen)的濃度是成年女性的10倍。
In the 12th week of pregnancy, the concentration of estrogen in the fetal blood is 10 times that of an adult female.
這是因為胚胎需要性激素來促進生殖器官的發育。在妊娠早期,胎兒的性腺(卵巢或睪丸)還沒有發育成熟,因此性激素主要由母體的卵巢或胎盤分,之後在青春期前,性激素的分泌量會逐漸降低。這是因為在青春期之前,人體的性腺還沒有完全發育成熟。在青春期後,性激素的分泌量會再次增加,並達到成人水平。
This is because the embryo needs sex hormones to promote the development of the reproductive organs. In early pregnancy, the fetal gonads (ovaries or testicles) have not yet matured, so sex hormones are mainly secreted by the mother's ovaries or placenta.
After that, the secretion of sex hormones will gradually decrease before puberty. This is because the sex glands in the human body have not yet fully matured before puberty. After puberty, the secretion of sex hormones will increase again and reach adult levels.

腦下垂體前葉

腦下垂體前葉的分泌物,有:促甲狀腺素(thyroid-stimulating hormone)、促腎上腺皮質素(adrenocorticortropic hormone)及生長激素(growth hormone)。

生長激素(Growth Hormone,GH)是一種由腦下垂體分泌的重要激素,其作用範圍涵蓋身體的多個方面,包括生長、代謝、免疫和細胞修復。
高強度運動(high intensity exercise)能促進腦垂體分泌生長激素(growth hormone),可促進骨骼、肌肉和器官生長也可以促進脂肪分解,幫助減肥。
例如在進行 30 分鐘高強度間歇訓練 (HIIT) 後,受試者的生長激素水平比休息時高出 450%。
High-intensity exercise (HIE) can promote the secretion of growth hormone (GH) from the pituitary gland. GH promotes the growth of bones, muscles, and organs, and can also promote lipolysis and help with weight loss.
For example, after 30 minutes of high-intensity interval training (HIIT), subjects' GH levels were 450% higher than at rest.

然而,研究顯示,長期過量的生長激素可能與胰島素節抗有關,其中一個機制是減少胰島素受體數目。

胰島素受體位於細胞膜上,它們是胰島素作用的關鍵部位,通過與胰島素結合,促使細胞內的葡萄糖攝入。然而,過量的生長激素可能會導致胰島素受體數目減少,從而減弱細胞對胰島素的敏感性,使得細胞對胰島素的反應減弱,甚至產生胰島素抵抗。

胰島素抵抗是一種導致血糖升高的情況,這可能導致糖尿病和其他代謝性疾病的風險增加。因此,生長激素過量可能通過減少胰島素受體數目,影響胰島素代謝,進而對代謝健康產生影響。 

糖尿病相關藥物

Alogliptin 是一種 DPP-4 抑制劑,可以減少胰島素的分解,從而增加胰島素的活性。
Alogliptin is a DPP-4 inhibitor that works by reducing insulin breakdown, thereby increasing insulin activity.

canagliflozin是一種鈉-葡萄糖轉運蛋白 2 (SGLT2) 抑制劑,SGLT2 是位於腎臟近端小管的轉運蛋白,負責將葡萄糖從尿液中重新吸收回血液,其主要作用機制為抑制SGLT2 的活性,減少葡萄糖再吸收,增加葡萄糖從尿液排除的量來降低血糖。
Canagliflozin is a sodium-glucose cotransporter 2 (SGLT2) inhibitor. SGLT2 is a transporter protein located in the proximal tubule of the kidney that is responsible for reabsorbing glucose from the urine back into the blood. Canagliflozin works by inhibiting the activity of SGLT2, reducing glucose reabsorption, and increasing the amount of glucose excreted in the urine to lower blood sugar.

Empagliflozin 是一種 SGLT2 抑制劑,可以增加尿液中的葡萄糖排泄,對於有心血管疾病併發症的糖尿病患者來說,Empagliflozin 是一個不錯的選擇。
Empagliflozin is a SGLT2 inhibitor that works by increasing urinary glucose excretion. It is a good choice for people with type 2 diabetes who have cardiovascular disease complications.

Insulin glulisine 是一種胰島素類似物,可以直接作用於胰島細胞,刺激胰島素的分泌。Insulin glulisine 是一種強效降血糖藥物,因此對於有嚴重併發症的糖尿病患者來說,Insulin glulisine 可以幫助快速控制血糖。

Insulin glulisine is an insulin analog that works by directly stimulating insulin secretion from pancreatic beta cells. It is a potent hypoglycemic drug, so it can help to quickly control blood sugar in people with severe diabetes complications.

Metformin 是一種口服降血糖藥物,主要作用是減少肝臟的葡萄糖生成,並增加胰島素對葡萄糖的敏感性,最適合給與初診斷為第二型糖尿病且尚無併發症之病人
Metformin is an oral hypoglycemic drug that works by reducing hepatic glucose production and increasing insulin sensitivity. It is the preferred first-line therapy for newly diagnosed type 2 diabetes without any complications.

松果體 

(又叫做松果腺、腦上體或第三隻眼)是一個位於脊椎動物腦中的小內分泌腺體。它負責製造褪黑素,一種會對醒睡模式與(季節性)晝夜節律(en:Circadian rhythm)功能的調節產生影響的激素其形狀像是一顆小松果(這也是其名字的由來),並座落在腦部中央的附近,介於兩個大腦半球(en:Cerebral hemisphere)之間,被裹在兩個圓形的丘腦的接合處。從神經外胚層(neuroectoderm)化而來。 

腮腺 


腮腺是最大的唾液腺,主要位於耳朵的前下方所以又俗稱耳下腺,其導管穿過頰肌開口於口腔,其分泌液內含唾液澱粉酶 


甲狀腺體 

位置:甲狀腺於頸部甲狀軟骨下方(大約頸部喉結下方),氣管的兩旁,形狀像蝴蝶 功能:甲狀腺吸收血液中的碘,生成並分泌甲狀腺素 (荷爾蒙),有調節身體細胞的新陳代謝、生長及發育的作用。 而甲狀腺素的分泌是由腦部腦下垂體所分泌的促甲狀腺激素所調節。高敏感性促甲狀腺激素 (hsTSH): 促甲狀腺激素由腦下垂體所分泌,促進甲狀腺生成和分泌甲狀腺素,因此腦下垂體本身的狀況會影響促甲狀腺激素的分泌。 

降鈣素及骨質密度

關於骨質密度/About bone mineral density
1. 雙羥維生素 D〔1,25-(OH)2D〕是一種活性維生素 D,可以促進腸道對鈣的吸收,並抑制骨骼的破骨細胞活性,有利於增加骨質密度。
25-dihydroxyvitamin D (calcitriol) is an active form of vitamin D that promotes calcium absorption in the intestine and inhibits bone resorption. Therefore, an increase in calcitriol levels is beneficial for increasing bone mineral density.

2. 降鈣素(英語:Calcitonin,又譯為抑鈣激素)是一種負反饋調節激素(含有32個胺基酸的直線型多肽類激素),在人體裡是由甲狀腺的濾泡旁細胞(parafollicular cells,又稱C細胞)製造,,它可以抑制骨骼破骨細胞的活性,從而減少骨質流失。但降鈣素濃度下降並不能直接增加骨質密度,因為它只是抑制了骨質流失的速度,而不能增加骨質的形成。
Calcitonin is a negative feedback hormone that inhibits bone resorption. However, a decrease in calcitonin levels does not directly increase bone mineral density because it only inhibits the rate of bone loss, not the formation of bone.

甲狀腺的濾泡旁細胞(parafollicular cell of thyroid gland)分泌激素的主要功能,與副甲狀腺素(parathyroid hormone)的作用相反,相反的地方主要是呈現在血鈣的影響。
副甲狀腺素會促進骨骼的鈣釋放、減少尿液中鈣的排泄,以及增加腸道對鈣的吸收,而甲狀腺濾泡旁細胞分泌的降鈣素則會讓鈣沉積在骨骼、增加尿液中鈣的排泄,也減少腸道對鈣的吸收

The main function of the hormone secreted by the parafollicular cells of the thyroid gland is opposite to that of parathyroid hormone, mainly in terms of their effects on blood calcium levels.

Parathyroid hormone (PTH) promotes the release of calcium from bones, decreases the excretion of calcium in the urine, and increases the absorption of calcium from the intestines. On the other hand, calcitonin, which is secreted by the parafollicular cells of the thyroid gland, promotes the deposition of calcium in bones, increases the excretion of calcium in the urine, and decreases the absorption of calcium from the intestines.

3. 皮質醇是一種糖皮質激素,它可以抑制骨骼的形成,並促進骨質流失。
Cortisol is a glucocorticoid that inhibits bone formation and promotes bone loss.

4. 雌激素是一種女性激素,它可以促進骨骼的形成,並抑制骨質流失。因此,皮質醇濃度上升和雌激素濃度下降都會不利於增加骨質密度。
Estrogen is a female sex hormone that promotes bone formation and inhibits bone loss. Therefore, an increase in cortisol levels and a decrease in estrogen levels are both detrimental to increasing bone mineral density.

膠體

甲狀腺是由許多濾泡所組織成的,每個濾泡就像一個中空的球形,在濾泡腔中含有膠體,儲存有甲狀腺荷爾蒙。此外有一些神經脊來源的細胞,散佈於濾泡之間,稱為濾泡旁細胞或C細胞。濾泡上皮細胞可分泌三碘甲狀腺素(T3)和甲狀腺素(T4)等甲狀腺荷爾蒙;

甲狀腺是由濾泡所組成,而其中有膠體(Colloid)的構造,來儲存甲狀腺賀爾蒙。 

副甲狀腺體 

位置:甲狀腺後方有4顆像豌豆的小腺體 功能:分泌副甲狀腺荷爾蒙。它的主要作用是維持體內血鈣濃度在正常範圍內,低血鈣主要會刺激副甲狀腺內分泌腺體的激素分泌,以增加血鈣濃度,若手術不小心移除副甲狀腺,最可能造成血鈣濃度下降。。使肌肉與神經系統能運作正常,雖然它與甲狀腺在解剖位置上相當靠近,但兩者的功能卻不相關 

腎上腺體 

腎上腺體位置:腎上腺位於胸腹中、腎臟之前上方 腎上腺體功能:其主要功能為通過合成皮質類甾醇和鄰苯二酚胺(例如皮質醇和腎上腺素)來調控身體對壓力產生的反應。 若因自體免疫破壞所有腎上腺皮質組織時,腎上腺皮質激素與雄激素合成會受影響。 

嗜鉻性細胞(chromaffin cells)

主要位於腎上腺髓質(medulla of adrenal gland)中。

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