Âèâ÷åííÿ ôóíêö³îíàëüíèõ îñîáëèâîñòåé ùèòîïîä³áíî¿ çàëîçè ïðèâåðòàëî óâàãó â÷åíèõ ùå íà ðàíí³õ åòàïàõ ðîçâèòêó íàóêè. Ç ðîçâèòêîì åíäîêðèíîëî㳿 áóëî âñòàíîâëåíî, ùî äîñòàòíº íàäõîäæåííÿ éîäó º íåîáõ³äíîþ óìîâîþ äëÿ íîðìàëüíîãî ñèíòåçó òèðåî¿äíèõ ãîðìîí³â òà ï³äòðèìàííÿ ôóíêö³îíàëüíî¿ àêòèâíîñò³ ùèòîïîä³áíî¿ çàëîçè [1, 2, 3].
Ãîëîâíèìè ãîðìîíàìè, ùî ñåêðåòóº ùèòîïîä³áíà çàëîçà (ÙÇ), º òèðîêñèí (Ò4), òðèéîäòèðîí³í (Ò3), òà îáåðíåíèé òðèéîäòèðîí³í (ÎÒ3) [4]. Òðèéîäòèðîí³í òàêîæ óòâîðþºòüñÿ â ïåðèôåð³éíèõ òêàíèíàõ øëÿõîì äåéîäóâàííÿ Ò4. Ò3 º á³îëîã³÷íî àêòèâí³øîþ ôîðìîþ òèðåî¿äíèõ ãîðìîí³â, òîä³ ÿê òèðîêñèí âèêîíóº ïåðåâàæíî ðîëü ïðîãîðìîíó [1, 2, 3, 5]. ×àñòèíà ãîðìîí³â ìåòàáîë³çóºòüñÿ ç óòâîðåííÿì ÎÒ3, â³í âèÿâëåíèé â íåâåëèê³é ê³ëüêîñò³ ó âåíîçí³é êðîâ³ ÙÇ ³ º íåàêòèâíèì [1, 6, 7].
Éîä, ùî íàäõîäèòü äî îðãàí³çìó ç ¿æåþ, âñìîêòóºòüñÿ â êèøê³âíèêó ó âèãëÿä³ éîäèäó òà òðàíñïîðòóºòüñÿ êðîâʼþ äî ùèòîïîä³áíî¿ çàëîçè (ÙÇ). Ó êë³òèíàõ çàëîçè â³í âêëþ÷àºòüñÿ â ïðîöåñ ñèíòåçó òèðåî¿äíèõ ãîðìîí³â. ϳä 䳺þ ôåðìåíòó òèðåîïåðîêñèäàçè â³äáóâàºòüñÿ îêèñíåííÿ éîäó òà éîãî çâʼÿçóâàííÿ ç çàëèøêàìè òèðîçèíó, ùî âõîäÿòü äî ñêëàäó òèðåîãëîáóë³íó – îñíîâíîãî á³ëêà êîëî¿äó ôîë³êóë³â ùèòîïîä³áíî¿ çàëîçè. Ó ðåçóëüòàò³ öèõ ïðîöåñ³â óòâîðþþòüñÿ ìîíîéîäòèðîçèí (̲Ò) òà äèéîäòèðîçèí (IJÒ) [1, 2]. Ïîäàëüøà êîíäåíñàö³ÿ öèõ ñïîëóê ïðèçâîäèòü äî óòâîðåííÿ òèðåî¿äíèõ ãîðìîí³â: ïðè çʼºäíàíí³ äâîõ ìîëåêóë Ä²Ò ôîðìóºòüñÿ òèðîêñèí (Ò4), òîä³ ÿê êîìá³íàö³ÿ Ì²Ò ³ Ä²Ò ïðèçâîäèòü äî óòâîðåííÿ òðèéîäòèðîí³íó (Ò3) [1, 2, 5]. Ñèíòåçîâàí³ ãîðìîíè çáåð³ãàþòüñÿ ó ñêëàä³ òèðåîãëîáóë³íó â êîëî¿ä³ ôîë³êóë³â ùèòîïîä³áíî¿ çàëîçè. ϳä ÷àñ ñòèìóëÿö³¿ òèðåîöèò³â òèðåîãëîáóë³í çàõîïëþºòüñÿ êë³òèíàìè øëÿõîì åíäîöèòîçó, ï³ñëÿ ÷îãî ï³ä 䳺þ ïðîòåîë³òè÷íèõ ôåðìåíò³â â³äáóâàºòüñÿ âèâ³ëüíåííÿ òèðåî¿äíèõ ãîðìîí³â, ÿê³ íàäõîäÿòü ó êðîâîò³ê. Íåâèêîðèñòàí³ éîäîâàí³ ñïîëóêè ï³ääàþòüñÿ äåéîäóâàííþ, à âèâ³ëüíåíèé éîä ïîâòîðíî âèêîðèñòîâóºòüñÿ ùèòîïîä³áíîþ çàëîçîþ äëÿ ñèíòåçó ãîðìîí³â [1, 2].
Çíà÷íà ÷àñòèíà òðèéîäòèðîí³íó óòâîðþºòüñÿ òàêîæ ó ïåðèôåðè÷íèõ òêàíèíàõ øëÿõîì äåéîäóâàííÿ òèðîêñèíó, ùî º îñíîâíèì øëÿõîì ôîðìóâàííÿ á³îëîã³÷íî àêòèâíî¿ ôîðìè òèðåî¿äíèõ ãîðìîí³â.
Ôóíêö³þ ÙÇ ðåãóëþþòü, ïåðø çà âñå, çì³íè öèðêóëþþ÷îãî ð³âíÿ òèðåîòðîïíîãî ãîðìîíó (ÒÒÃ), ùî ñèíòåçóºòüñÿ ïåðåäíüîþ ÷àñòêîþ ã³ïîô³çó ³ º ãë³êîïðîòå¿íîì òà ñêëàäàºòüñÿ ç äâîõ íåêîâàëåíòíî çâ’ÿçàíèõ ì³æ ñîáîþ ñóáîäèíèöü: α ³ β [1,2]. ÒÒÃ-α ³äåíòè÷íà äî α-ñóáîäèíèö³ ëþòå¿í³çóþ÷îãî (ËÃ), ôîë³êóëîñòèìóëþþ÷îãî (ÔÑÃ) ãîðìîí³â òà õîð³îí³÷íîãî ãîíàäîòðîï³íó ëþäèíè (ÕÃë). Ôóíêö³îíàëüíà çäàòí³ñòü ãîðìîí³â ã³ïîô³çó, â òîìó ÷èñë³ ³ ÒÒÃ, ïîâ’ÿçàíà ç β-ñóáîäèíèöåþ [4, 8]. Ñåêðåö³ÿ ÒÒà º öèêë³÷íîþ, çðîñòàííÿ ¿¿ ïî÷èíàºòüñÿ áëèçüêî äåâ’ÿòî¿ ãîäèíè âå÷îðà, äîñÿãຠìàêñèìàëüíîãî çíà÷åííÿ îï³âíî÷³, çíèæóþ÷èñü ïðèòÿãîì äíÿ, ïðè ÷îìó íîðìàëüíèé ¿¿ ð³âåíü ñòàíîâèòü áëèçüêî 110 ìêã/äîáó, ñåðåäí³é ð³âåíü ÒÒà ó ïëàçì³ ñêëàäຠ2 ìêÎÄ/ìë [1, 2, 5]. ϳä 䳺þ ÒÒà óïðîäîâæ ê³ëüêîõ õâèëèí â³äáóâàºòüñÿ ïîñèëåííÿ çàõîïëåííÿ éîäó ÙÇ, à òàêîæ àêòèâóþòüñÿ ïðîöåñè ñèíòåçó Ò3, Ò4, ̲Ò, IJÒ, ñåêðåö³ÿ Òà â êîëî¿ä òà éîãî åíäîöèòîç.
Ñåêðåö³ÿ òèðåîòðîïíîãî ãîðìîíó ðåãóëþºòüñÿ ìåõàí³çìîì íåãàòèâíîãî çâîðîòíîãî çâʼÿçêó: çíèæåííÿ êîíöåíòðàö³¿ â³ëüíèõ òèðåî¿äíèõ ãîðìîí³â ó êðîâ³ ñòèìóëþº ï³äâèùåíå âèä³ëåííÿ ÒÒà àäåíîã³ïîô³çîì, ùî, ó ñâîþ ÷åðãó, àêòèâóº ñèíòåç ãîðìîí³â ùèòîïîä³áíî¿ çàëîçè [1, 8]. Êëþ÷îâó ðîëü ó ðåãóëÿö³¿ ö³º¿ ñèñòåìè â³ä³ãðຠòèðåîòðîï³í-ðèë³çèíã-ãîðìîí (ÒÐÃ), àáî òèðîë³áåðèí, ÿêèé âïåðøå â 1969 ðîö³ áóâ âèä³ëåíèé äâîìà ãðóïàìè äîñë³äíèê³â Guillemin R. òà Schally A.V. íåçàëåæíî îäèí â³ä îäíîãî ³ç ã³ïîòàëàìóñà â³äïîâ³äíî ñâèíåé òà îâåöü. Òèðîë³áåðèí âèêîíóº ðîëü ðåãóëÿòîðà âñ³º¿ ã³ïîòàëàìî-ã³ïîô³çàðíî-òèðåî¿äíî¿ ñèñòåìè [2, 4, 8], ïðè éîãî ââåäåíí³ øâèäêî ï³äâèùóºòüñÿ ñåêðåö³ÿ ÒÒà ã³ïîô³çîì, à òàêîæ ñïîñòåð³ãàºòüñÿ ïîñèëåíå âèä³ëåííÿ ïðîëàêòèíó.
Òàêèì ÷èíîì, ã³ïîòàëàìî-ã³ïîô³çàðíî-òèðåî¿äíà ñèñòåìà º êëþ÷îâèì ìåõàí³çìîì ðåãóëÿö³¿ ôóíêö³îíàëüíîãî ñòàíó ùèòîïîä³áíî¿ çàëîçè òà ï³äòðèìàííÿ ãîðìîíàëüíîãî áàëàíñó îðãàí³çìó. Ãàðìîí³éíà âçàºìîä³ÿ ¿¿ êîìïîíåíò³â çàáåçïå÷óº ñòàá³ëüíèé ñèíòåç òèðåî¿äíèõ ãîðìîí³â ³ ñïðèÿº ï³äòðèìàííþ ãîìåîñòàçó îðãàí³çìó. Ïîðóøåííÿ æ ¿¿ ôóíêö³¿ ìîæóòü âïëèâàòè íà ³íø³ åíäîêðèíí³ ñèñòåìè, çîêðåìà ðåïðîäóêòèâíó, ñïðè÷èíÿþ÷è ðîçâèòîê ôóíêö³îíàëüíèõ ðîçëàä³â [8].
Ñïèñîê ë³òåðàòóðè:
1. National Institutes of Health, Office of Dietary Supplements. Iodine: Fact Sheet for - Health Professionals. - Bethesda (MD): NIH. URL: https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/
2. Zimmermann M. B., Boelaert K. Iodine deficiency and thyroid disorders Lancet Diabetes Endocrinol. 2015. Vol. 3, ¹ 4. P. 286-295.
3. Sieiro N. L., Medina C. C., Micmacher E. et al. Influence of thyroid autoimmunity and maternal age on the risk of miscarriage. American journal of reproductive immunology. 2004. Vol. 52, ¹ 5. P. 312-316. doi:10.1111/j.1600-0897.2004.00227.x
4. Tańska K., Gietka-Czernel M., Glinicki P., Kozakowski J. Thyroid autoimmunity and its negative impact on female fertility and maternal pregnancy outcomes.
Front Endocrinol (Lausanne). 2023. Vol. 13: 1049665. doi:10.3389/fendo.2022.
1049665.
5. Sher G., Maassarani G., Zouves C. et al. The use of combined heparin/aspirin and immunoglobulin G therapy in the treatment of in vitro fertilization patients with antithyroid antibodies. American journal of reproductive immunology. 1998. Vol. 39, ¹ 4. P. 223-225. doi:10.1111/j.1600-0897.1998.tb00357.x
6. Singh A., Dantas Z. N., Stone S. C., Asch R. H. Presence of thyroid antibodies in early reproductive failure: biochemical versus clinical pregnancies. Fertility and sterility. 1995. Vol.63, ¹ 2. P. 277-281.
7. Stagnaro-Green A., Roman S.H., Cohen R. H. et al. A prospective study of lymphocyte-initiated immunosuppression in normal pregnancy, evidence of a
T-cell etiology for postpartum thyroid dysfunction. The Journal of clinical endocrinology and metabolism. 1992. Vol. 74. P. 645-653. doi:10.1210/jcem.74.3.1740500
8. Concepción-Zavaleta M.J., Coronado-Arroyo J.C., Quiroz-Aldave J.E., Concepción-Urteaga L.A., Paz-Ibarra J. Thyroid dysfunction and female infertility: a comprehensive review. Diabetes and metabolic syndrome. 2023. Vol. 17, ¹ 11. 102876. doi:10.1016/j.dsx.2023.102876.
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Íàóêîâèé êåð³âíèê: Ïàí÷óê Îëüãà Âîëîäèìèð³âíà, êàíäèäàò á³îëîã³÷íèõ íàóê, ñòàðøèé âèêëàäà÷ êàôåäðè á³îëî㳿, Íàö³îíàëüíèé ìåäè÷íèé óí³âåðñèòåò ³ìåí³ Î. Î. Áîãîìîëüöÿ, ì.Êè¿â, Óêðà¿íà
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