Pharmacology Teaching and Research

Online Lecture: Endocrine System

Drugs Affecting the Endocrine System - Estrogens and Androgens


Estrogens are hormones that are important for sexual and reproductive development, mainly in women.

They are also referred to as female sex hormones.

The term "estrogen" refers to all of the chemically similar hormones in this group, which are estrone, estradiol (primary in women of reproductive age) and estriol.

Testosterone is the principal circulating androgen in men, secreted almost entirely by the testes.

The effects of testosterone on bone in men are therefore best observed when they are deficient in testosterone and then replaced with testosterone.

The effects of physiologic concentrations of testosterone in men, as observed in these situations, are substantial.

Testosterone is also the principal circulating androgen, in potency, in women. It is secreted by the ovaries and the adrenal glands, and derived also by peripheral conversion of the weak adrenal androgens, androstenedione and dehydroepiandrosterone.

The normal serum concentration of testosterone in women, however, is only approximately 10% of that in men, and the effect of testosterone on bone in women is therefore much less clear than in men.

Click below for a Presentation - Estrogens and Androgens.