Table 1 Major steroids and their physiological functions

Ovary

Granulosa cells

FSH

Estradiol

Estrogen, a principal female sex steroid, required for growth and ovulation, responsible for secondary female sex characteristics, regulator of cardiovascular physiology, bone integrity and neuronal growth

Luteinized Granulosa/luteal Cells

LH

Progesterone

A progestin, required for follicular growth and ovulation, responsible for changes associated with luteal phase of the menstrual cycle, essential for the establishment and maintenance of early pregnancy

Theca-interstitial Cells

LH

Testosterone Androstenedione

Androgens, precursors for estrogens, transported into granulosa cells, where they are converted into estardiol and other estrogens by aromatase (CYP19A1) enzyme

Testis

Leydig cells

LH

Testosterone

The most prevalent male sex hormone (androgen); testosterone and its biologically active form, dihydrotestosterone (DHT) are necessary for normal spermatogenesis and development, responsible for secondary sex characteristics, responsible for increased muscle mass, sexual function, body hair and decreased risk of osteoporosis

Adrenal gland

Z. glomerulosa Cells

ACTH, K⁺ Angiotensin II

Aldosterone

The principal mineralocorticoid, raises blood pressure and fluid volume, enhances sodium reabsorption in the kidney, sweat gland, stomach and salivary gland and also enhances excretion of potassium and hydrogen ions from the kidney.

Z. glomerulosa Cells

ACTH

Cortisol

The dominant glucocorticoid in humans (in rodents, the major glucocorticoid is corticosterone), elevates blood pressure and Na⁺ uptake, involved in stress adaptation, regulates carbohydrate, protein and lipid metabolism nearly opposite to that of insulin, influences inflammatory reactions and numerous effects on the immune system.

Z. reticularis Cells

ACTH POC-derived peptide Other factors

Androstenedione DHEA DHEA-sulfate

The function of adrenal androgens is not well understood, except that they contribute to the maintenance of secondary sex characteristics, may also be involved in the regulation of bone mineral density, muscle mass and may beneficial actions against type 2 diabetes and obesity

Placenta

Peptide growth Factors, cAMP

Progesterone Estrogens

Maintenance of pregnancy

Brain

Neurons, Glial cells Purkinje cells

Neurotransmitters Neuropeptides

Progesterone Estradiol, DHEA, ALLO, THDOC

Neurosteroids are implicated in various processes such as proliferation, differentiation, activity and survival of nerve cells and a variety of neuronal functions including control and behavior, neuroendocrine and metabolic processes.