Cau 29: cac hormon vo thuong than: ban chat, tac dung, dieu hoa bai tiet va UDLS

*) Ban chat:

- Cac hormon vo th than deu la hchat steroid. Chung deu co 1 nhan chung la nhan steroid hay cyclopentanoperhydrophenanthren

- Hormon vo thg than dc chia lam 2 nhom:

+ nhom 19 carbon co nhan co ban la androstan. Cac hormon sinh duc co nguon goc tu vo thg than thuoc nhom nay.

+ nhom 21C co nhan co ban la pregnan bao gom cac hormon vo chuyen hoa dg va chuyen hoa muoi nc.

*) tac dung :

a) Cortisol

1. tac dung len chuyen hoa glucid

- tang tao duong moi o gan (muc tang tu 6 - 10 lan)

+ Cortisol lam tang tat ca cac enzym tham gia

+ cortisol lam tang huy dong a.a tu cac mo ngoai gan

- giam nhe muc tieu thu glucose cua TB o khap moi noi trong co the

-> tang dg huyet va co the gay dai thao dg

2. tac dung len chuyen hoa pr

- giam pr cua TB (giam du tru pr cua tat ca Tb trong co the tru gan. Tac dung nay la do 1 mat lam tang thoai hoa pr o TB, mat khac lam giam sinh tong hop pr

- tang vc a.a vao TB gan dong thoi lam tang ham lg enzym tham gia vao qua trinh sinh tong hop pr o gan -> lam tang su dung pr o TB gan

- tang Cm a.a huyet tg dong thoi giam vc a.a vao TB tru gan

3. tac dung len chuyen hoa lipid

- tang thoai hoa lipid o cac mo mo -> tang Cm acid beo tu do trong huyet tg

- tang oxy hoa acid beo tu do o cac TB de tao nang lg

Khi cortisol dc bai tiet qua nhieu thi lai co tac dung lam tang lang dong mo va roi lan phan bo mo trong co the. Trong nhung TH nay mo u dong o mat, nguc, bung

4. Tac dung chong stress

- trong tinh trang stress ngay lap tuc [ACTH] tang trong mau sau vai phut su bai tiet cartisol cung tang len -> chong lai dc cac stress

- nhung loan stress co td lam tang [cortisol] : chan thuong, nhiem khuan cap, qua nong or qua lanh, phau thuat, tiem cac chat gay hoai tu duoi da,hau het cac benh gay suy nhuoc, su cang thang TK qua muc

5. Tac dung chong viem :

- cortisol co td lam giam tat ca cac gd cua qtrinh viem -> chong viem manh. Co che :

+ cortisol lam vung ben mang lysosom. Do do lysosom kho phong cang va kho vo

+ cortisol uc che enzym phospholipase A2 la enzym tgia trong qua trinh tong hop prostaglandin, leukotien do vay lam giam pu viem boi chinh 2 hop chat nay gay ra gi•n mach, tang nhiet do, tang tinh tham cua mao mach

6. tac dung chong di ung :

- khi co di nguyen xam nhap vao co the, pu ket hop giua di nguyen va khang the xay ra va keo theo 1 chuoi cac pu di ung.

- 1 dac tinh dac biet cua IgE la co knang gan manh voi duong bao va bach cau ua toan khi di nguyen pu voi khang the IgE. Phuc hop nay se gan vao be mat cua duong bao or bach cau ua kiem va ngay lap tuc lam thay doi tinh tham cua mang Tb duong bao va bach cau ua kiem lam cho TB nay vo va giai phong cac chat co td gi•n mach, tang tinh tham cua mao mach nhu histamin -> giam htuong di ung

7. tac dung len Tb mau va he thong mien dich

- lam giam bach cau ua toan va bach cau lympho

- lam giam kick thuoc cac mo lympho trong co the : giam kick thuoc hach tuyen uc

- lam giam sx lympho T va khang the

- lam tang san sinh HC

8. cac td khac :

- tang bai tiet HCl trong dich vi -> dung cortisol keo dai co the gay viem loet da day

- Cm cortisol tang no se uc che hinh thanh xuong = cach giam qtrinhtang sing Tb, giam sinh tong hop ARN, pr, collagen cua xg.

*) Dieu hoa : Cortisol dc bai tiet nhieu hay it phu thuoc vao Cm ACTH of tuyen yen, Cm ACTH tang lam cortisol dc bai tiet nhieu va ngc lai

b) aldosteron

*) Toc dung :

Thieu toan bo hormon vo thuong than se dan toi chet trong vong vai ngayden vai tuan tru phi ng do dc tiep muoi lien tuc or tiem hormon vo chuyen hoa muoi nc

- tang tai hap thu ion Na+ va tang bai xuat K+ o TB ong than

Aldosterom khi den Tb ong than (db la ong luon xa va ong gop) se hoat hoa he gen o nhan TB va lam tang tong hop cac enzym va pr van tai 1 trong nhung enzym do la Na+, K+ - ATPase

- tac dung len the dich ngoai bao va HADM

Neu Cm aldosteron tang cao co the lam tang the tick dick ngoai baotf 5 - 15% va tang HADM tu 15 - 25mmHg

Ngc lai khi Cm aldosteron giam xuong = 0, 1 lg lon ion Na+ se bi mat qua dg nc tieu, ko chi the ma the tick dick ngaoi bao cung giam. Mat khac khi thieu aldosteron, Cm ion K+ trong dich ngoai bao se tang cao. Khi K+ tang tu 60 - 100% tren muc bthuong thi se gay ngo doc tim, co tim ko co dc do do ko bom dc mau

- tac dung cua aldosteron voi TB ong tuyen mo hoi va ong tuyen nc bot : aldosteron lam tang tai hap thu ion Na+ va tang bai xuat ion K+. Td nay db quan trong trong khi co the lam viec trong moi truong nong. Nho co aldosteron ma viec mat muoi qua con dg bay mo hoi se giiam bot

*) Dieu hoa bai tiet :

- tang Cm ion K+ trong dich ngoai bao se lam tang bai tiet aldosteron.

- tang hd cua he thong renin - angiotensin trong TH mat mau cung lam tang bai tiet aldosteron

- tang Cm ion Na+ trong dich ngoai bao lam giam nhe aldosteron

c) tac dung cua androgen

- o nam gioi : voi cnang bthuong cua tuyen sinh duc thi testosteron va dihydrotestosteron co nguon goc vo thg than chi chiem mot lg nho trong tong lg hormon sinh duc nam do vay td sinh hoc cua no ko dang ke. a nam truong thanh, su bai tiet qua muc cua androgen vo thg than ko gay ra bieu hien lsang nhung o tre con no se lam duong vat to trc tuoi truong thanh, lam phat trien cac dac tinh sinh duc thu phat trc tuoi day thi

- o nu gioi : trong TH cnang cua tuyen sd nu binh thg lg androgen bthuong do vo tuyen thg than bai tiet se ko gay bieu hien bat thg. Tuy nhien, neu vo tuyen thg than bai tiet qua nhieu androgen nhu hoi chung cushing, u tuyen thg than or tang san thg than bam sinh thi se gay ra htg nam hoa