Professor Howard Jacobs
Emeritus Professor of Endocrinology

{C}The function and interaction between the Pituitary gland and the Sex hormones

The pituitary gland produces Luteinising hormone (LH) and follicle stimulating hormone (FSH), which stimulate hormone production by the Gonads. In women, the ovaries produce Oestrogen and Progesterone, causing the release of eggs. In men, Testosterone is produced by the testes.

Fertility issues in women

Cessation of periods (Amenorrhoea) can be caused by overproduction of Prolactin, a hormone that stimulates milk production for breast-feeding. Excessive prolactin secretion that is unrelated to childbirth switches off the hypothalamic-pituitary axis (i.e. LH/FSH) and so menstrual cycles stop. Menopause is a state when the ovaries are not working, i.e. oestrogen and progesterone levels are low and LH and FSH levels are raised. In contrast, hypothalamic and pituitary malfunction cause low level production of these hormones.

Fertility issues in men

If levels of LH and FSH fall, testicular function declines. As testicular function wanes, testosterone levels fall and erectile dysfunction (impotence) occurs.

Reproductive malfunction

The most common cause of infertility in pituitary disease is a raised prolactin level. Too much prolactin can cause malfunction of the reproductive organs. Men can loose their libido, causing a reduced response by them to others and subsequently become impotent. Women can also lose their libido, and oestrogen deficiency can cause vaginal atrophy (break down of tissue) and discomfort. If prolactin levels are suppressed to normal then sexual function returns and the prognosis for fertility is excellent in both men and women once prolactin levels are lowered. Women wanting pregnancy can safely take Bromocriptine (a prolactin-lowering drug). Other causes of raised prolactin levels include taking anti-sickness drugs, antidepressants or oestrogen, and primary Hypothyroidism (an underactive thyroid condition). Events such as stress, divorce and bereavement may also cause raised prolactin levels.

Disturbed reproduction (low levels of LH and FSH)

When treating patients the medical profession should ask patients what they want. If women want to become pregnant, treatment is needed to mature eggs. This is achieved by replacing LH and FSH by injection to stimulate eggs. This can cause over-stimulation of eggs and result in multiple births. If pregnancies are not wanted then oestrogen and progesterone are replaced.

If men want to become fertile and have a family then testosterone is needed. A lack of LH and FSH results in the testes not producing sperm, as FSH is needed for sperm production and LH for testosterone production. LH injections (usually in the form of human chorionic gonadotrophin (HCG)) cause testosterone levels to rise, and FSH is given by injection two to three times a week to stimulate spermatogenesis. It may take 6 months to get sperm into the semen.

Questions from participants

Have testosterone patches been developed?

Not at the moment. Patches are superb for mimicking hormone levels, such as testosterone, but often have unpleasant side effects like skin rashes.

How do you treat Osteoporosis in men?

If testosterone levels are deficient then testosterone replacement therapy is given, but if testosterone levels are normal osteoporosis is treated using other drugs. Testosterone injections often cause fluctuation of hormone levels and mood swings. Testosterone tablets (Restandol) are poorly absorbed and you need to take tablets two to three times a day. Normal levels of testosterone are not usually achieved using testosterone replacement in tablet form.