Hormones of Adrenal Gland and their Function (with Diagram)

Seven important hormones of adrenal gland and their function are:

1. Growth hormone disorders 2. Antidiuretic Hormone disorders 3. Thyroid Hormone disorders 4. Parathyroid Hormone Disorder 5. Adrenal cortex disorders 6. Insulin Hormone Disorder 7. Testosterone Hormone Disorder.

Hormones are secreted in required amount from their respective endocrine glands. Over secretion (hyper secretion) or under secretion (hypo secretion) of hormones cause disease.

1. Growth hormone disorders:

Growth hormone (GH or STH) is secreted from the anterior lobe of the pituitary gland. Hypo secretion of GH in child causes dwarfism. Because of reduction in the skeletal growth, the body becomes small but well proportionate. Sexual immaturity is observed. It does not affect the intelligence of the person concerned.

Hyper secretion of GH in child (before sexual maturity) results in gigantism due to general overgrowth of skeleton. The affected individual grows to a height of 7 to 8 feet or more than that. Hyper secretion of GH in adult causes acromegaly, a disease characterised by disproportionate increase in the size of bones of face, hands and feet. As a result man develops a gorilla like appearance. Hypo secretion of GH in adult leads to a rare condition called ‘Simmond’s disease’. The patient becomes quite thin and shows signs of premature ageing.

2. Antidiuretic Hormone disorders:

Antidiuretic hormone (ADH) or vasopressin is secreted from the posterior lobe of the pituitary gland. Deficiency of ADH reduces reabsorption of water and hence excess water is lost through the dilute urine. This disorder is called diabetes insipidus. The patient feels very thirsty. But no glucose is lost in the urine of such a patient. Excessive secretion of ADH makes the blood dilute and low plasma sodium.

3. Thyroid Hormone disorders:

A. Hyperthyroidism:

Hyper secretion of thyroid hormones causes Grave’s disease or exophthalmic goiter (protrusion of eye ball). Rapid heartbeat, rise in blood pressure, slightly high body temperature, nervousness, irritability and restlessness are the symptoms of this disease (Fig. 2.4A).

B. Hypothyroidism:

Hypo secretion of thyroid hormones cause following diseases :

(i) Cretinism:

It is caused due to under secretion of thyroid hormones in infants. A cretin has slow body growth, mental development, metabolic rate. The other characteristics are: slow heart beat, low blood pressure, and decrease in temperature, pot-belly, pigeon chest, dry skin, thick tongue and retarded sexual development (Fig. 2.4B). This disease can be treated by early administration of thyroid hormones.

(ii) Myxoedema:

It is caused by the deficiency of thyroid hormones in adults. It is characterised by puffy skin due to deposit of fat below skin, low metabolic rate, slow heart beat, low blood pressure, low body temperature and retarded sexual development. This disease can be treated by the administration of thyroid hormones (Fig. 2.4D).

(iii) Simple goiter:

It is caused by the deficiency of iodine in the diet. Iodine is required for the synthesis of thyroid hormone. It causes the enlargement of thyroid gland. This disease is common in hilly areas. Consumption of iodised table salt prevents the occurrence of this disease. (Fig. 2.4C)

(iv) Hashimoto’s disease:

In this disease the thyroid gland is destroyed by autoimmunity. As a result, all thyroid functions are disturbed.

4. Parathyroid Hormone Disorder:

Parathyroid hormone or parathormone are secreted by parathyroid glands.

(i) Hyperparathyroidism:

Deficiency of parathormone cause a disease called parathyroid tetany. It causes lowering of blood calcium level. This increases the excitability of nerves and muscles. Prolonged muscle contraction (tetany) of larynx, face, hands and feet are produced.

(ii) Hyperparathyroidism. Break down of bone or osteoporosis is one of the evil effects of parat hormone. When an excess of parathormone is present, the bones become soft, some bone substances are replaced by fibrous connective tissue and calcium deposition in kidney.

5. Adrenal cortex disorders:

(i) Mineralocorticoids and glucocorticoids hormones disorders:

Mineralocorticoids and glucocorticoids are groups of hormones secreted by adrenal cortex. Deficiency of these hormones causes Addison’s disease. The symptoms of this disease include weight loss, weakness, nausea, vomiting, diarrhea, low blood sugar, low plasma Na⁺, high K⁺ plasma, pigmentation of skin.

(ii) Cortisol hormone disorder:

Hypersecretion of Cortisol from adrenal cortex cause a disease called cushing’s syndrome. It is characterised by high blood sugar, excretion of sugar in urine, high Na⁺ concentrations in plasma, low K⁺ concentration in plasma, rise in blood volume, high blood pressure, excessive deposition of fat in face, back of the neck, abdomen.

(iii) Aldosterone hormone disorder:

Excess secretion of aldosterone cause high Na⁺ concentration and low K⁺ concentration in the plasma, rise in blood volume and high blood pressure. This result in a disease called aldosterone’s.

(iv) Sex corticoid hormone disorder:

Excess of sex corticoids in female develop male secondary sexual characters such as beard, moustaches and hoarse voice resulting in a disease called as adrenal virilism.

(v) Female sex hormone disorder:

Excessive secretion of female sex hormone (oestrogen) in male enlarges the mammary glands or breasts in males.

6. Insulin Hormone Disorder:

Insulin hormone is secreted by beta cells of islet of Langerhans of pancreas. The primary function of insulin is to regulate blood glucose. Insulin deficiency causes diabetes mellitus. In this disease, the blood glucose level increases above normal (80 to 120 mg/100 ml). This condition is known as hyperglycemia.

When it exceeds 180 mg glucose appears in urine and this condition is known as glycosuria. The patient urinates frequently and cause excessive thirst (polydipsa). There is loss of weight due to break down of protein and fats. The person feels weak and tired. Abnormal fat metabolism occurs and over production of ketone bodies and acidosis may lead to diabetic coma and even death.

Sometimes failure of insulin to facilitate movement of glucose into cells causes diabetes mellitus. It is known as non-insulin-dependent diabetes mellitus (NIDDM).

When the blood glucose level falls below normal, it is called as hypoglycemia. It may be caused either by an excess of insulin and a deficiency of glucagon, or a failure of the secretion of the two hormones to completely regulate the blood sugar.

7. Testosterone Hormone Disorder:

Failure of testosterone secretion causes eunuchodism. This disease is marked by underdeveloped and non-functional secondary sex organs like prostrate, seminal vesicles and penis. External sex characters such as beard, moustaches are absent. The voice become low and they are unable to produce sperms.