The sci­ence of steroids

These fat-based chem­i­cal sig­nals send vi­tal mes­sages across the body

How It Works - - CONTENTS -

Steroid hor­mones are a group of chem­i­cal mes­sages made from choles­terol. This fatty, waxy sub­stance has four con­joined rings in its struc­ture, and this forms the back­bone of five types of long-range chem­i­cal sig­nals. Pro­duced in one part of the body, steroid hor­mones carry mes­sages to the tar­get cells via the blood­stream.

The first type are glu­co­cor­ti­coids, in­clud­ing the stress hor­mone, cor­ti­sol. Made in the adrenal glands above the kid­neys, it af­fects cells all over the body, re­duc­ing in­flam­ma­tion and con­trol­ling blood sugar and metabolism.

The se­cond type are min­er­alo­cor­ti­coids, the most im­por­tant of which is al­dos­terone. Also made in the adrenal glands, it sends mes­sages to the kid­neys to con­trol the body’s fluid lev­els. With­out al­dos­terone, the amount of salt and wa­ter in the body drops and po­tas­sium rises. This af­fects the heart­beat, which re­lies on the right amount of salts.

The third type are the an­dro­gens, the male sex hor­mones. The most ac­tive is testos­terone, pro­duced in the testes dur­ing and af­ter pu­berty. Testos­terone causes hair growth and changes to the vo­cal cords, bones, mus­cles and re­pro­duc­tive or­gans. The ovaries also make testos­terone but in smaller amounts.

The fourth and fifth types of steroid hor­mones are the oe­stro­gens and pro­gesto­gens, the fe­male sex hor­mones. Made by the ovaries, they work with hor­mones from the pi­tu­itary gland to con­trol the men­strual cy­cle. Oe­stro­gen rises dur­ing the first half of each cy­cle, and pro­ges­terone takes over for the se­cond half, pre­par­ing the body for preg­nancy.

Steroids have a dis­tinc­tive chem­i­cal struc­ture with four fused rings

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.