When hormones are secreted in normal quantities, a
dynamic effect is exerted in the maintenance of 'homeostasis and regulation of
biological processes'. If the production of the hormones is imbalanced by over
production or under production, the biological processes are disturbed, and
abnormalities occur. Some important disorders caused by hypo or hyper secretion
of hormones include dwarfism, gigantism, acromegaly, cretinism, simple goiter,
exophthalamic goiter, diabetes (mellitus and insipidus), Addison's disease, Cushing
syndrome etc.
Hypersecretion of growth stimulating hormone
(somatotropin), before puberty and completion of ossification, leads to an
abnormality called gigantism. This is 'over growth' of the skeleton resulting in
abnormal height of the person affected. Hypersecretion of this hormone in
adults results in an abnormality called acromegaly. This disease is characterized by enlargement of the
bones of the jaw, hand and feet, thickened nose, lips, eyelids and wide finger
tips and 'gorilla like appearance' of the person affected.
Hyposecretion of GH during childhood retards growth,
resulting in a 'pituitary dwarf / 'midget*. The pituitary dwarf is sexually and intellectually a
normal individual.
Over activity of the thyroid, cancer of the gland or
development of nodules of thyroid lead to hyperthyroidism. In adults abnormal
growth causes a disease called exophthalamic goiter, with characteristically
protruded eyeballs. Hyperthyroidism also affects the physiology of the body
(increased metabolic rate). Inadequate supply of iodine in the diet results in
hypothyroidism and enlargement of the thyroid gland. This condition is called simple goiter.
During pregnancy, due to hypothyroidism, defective development of the
growing baby leads to a disorder called cretinism. Physical grouth and mental growth gets severely
stunted {thyroid
dwarf] due
to untreated congenital
hypothyroidism' (deficiency of thyroid hormones by birth). Stunted growth, mental retardation, abnormal skin, low
intelligence quotient, deafness and mutism are some of the characteristic
features of this disease. In adult women, hypothyroidism may cause irregular
menstrual cycles. In adults the hypothyroidism results in a condition called myxedema. Lethargy, mental impairment,
intolerance to cold, puffiness of face and dry skin are some of the symptoms of
myxedema.
Over activity of parathyroid gland {hyper parathyroidism) causes excess decalcification
leading to bone deformities and fractures. Besides this, calcification of
kidneys takes place which results into stone formation and urinary problems.
Under activity of parathyroid gland (hypo-parathyroidism) leads to tetany (prolonged contraction of
muscles). The calcium ion levels in the blood decrease (hypocalcemia).
Under secretion of insulin by the pancreatic gland
(hypo-secretion) increases the level of glucose in blood (hyperglycemia).
Prolonged hyperglycemia is leads to a disease called diabetes mellitus, associated with the loss of glucose through urine
(glycosuria) and formation of harmful compounds called 'ketone bodies'. Insulin
therapy is used to treat diabetic patients.
Hyper secretion of insulin leads to decreased level of
glucose in the blood (hypoglycemia) resulting in insulin shock.
Deficiency
of vasopressin
causes a
disease called diabetes insipidus. It
does not involve loss of sugar
in urine (a difference from diabetes mellitus) .
Addison's disease is caused due to hyposecretion
of glucocorticoids by the adrenal cortex. This disease is characterised by loss
of weight, muscle weakness, fatigue and reduced blood pressure. Sometimes
darkening of the skin in the both exposed and nonexposed parts of the body occurs
in this disorder. This disorder does not allow an individual to respond to
stress.
Cushing's syndrome: It results due to over
production of glucocorticoids. This condition is characterized by breakdown of
muscle proteins and redistribution of body fat resulting in spindly arms and
legs accompanied by a round moon face, buffalo hump on the back and pendulous abdomen. Wound healing is poor. The
elevated level of Cortisols causes hyperglycemia, over the deposition of glycogen in liver and
rapid gain of weight.
