The names of the various hormones are long and may seem confusing to the reader. Various names and abbreviations have developed over the years. An effort will be made to keep this as systematic and simple as possible for case in reading and understanding.
The anterior lobe of the pituitary produces six separate hormones. These are as follows:
- Corticotrophin (also known as adrenocorticotrophin, abbreviated to ACTH). This hormone regulates the secretion of cortisol from the adrenal cortex (another endocrine gland located on top of the kidneys – it will be described in detail later on). Refer to Chapter 5. It also has a direct action on the skin, leading to increased pigmentation.
- Thyrotrophin (also known as thyroid- stimulating hormone, abbreviated to TSII). This hormone stimulates the thyroid gland in the neck into producing its hormones, which are called thyroxine and triiodothyroxine.
- Gonadotrophins. These consist of two parts. First there is the follicle-stimulating hormone (FSH), and second the luteinizing hormone (LH), which act on the gonads (the sex glands) in the pelvic area, and testes. They regulate the production of sperms and ova, and play a vital part in the reproductive processes. (LH is now the term used to replace the older one, testicular interstitial-cell stimulating hormone, in males.)
- Growth hormone (usually abbreviated to GH). This is concerned with normal body growth, and is particularly important in children, although it continues to be secreted throughout life.
- Prolactin. This hormone has various functions, some of which are not understood at present. It is involved with breast milk production, and also with ovulation. A considerable amount of research has been carried out on this hormone in the past few years, and some exciting practical results have accrued, particularly with women who appeared to be infertile.
- Melanocyte-stimulating hormone (MSH). This leads to a darkening of the skin in the same way as ACTH. It acts on the melanin cells in the upper skin layers that are the pigment cells of the skin.
The posterior lobe produces two important hormones. These are:
- Antidiuretic hormone (also called ADH or vasopressin). This plays an important part in controlling loss of water.
- Oxytocin. This is a powerful hormone exerting an effect on the uterus. Recent research has shown that these two hormones are actually manufactured in the hypothalamus, and are carried to the posterior pituitary where they are stored until required.