Animal Hormones

Animal Hormones:

Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most important in regards to control and development. The pituitary gland is responsible for the production of a hormone called somatotrophin. Somatotrophin is essential in the fact that it promotes mass production of proteins on a body-wide scale, by accelerating the rate of transport of amino acids; the constituents of a protein.
The same part of the pituitary gland is responsible for thyroid stimulating hormone or TSH for short. This targets the thyroid gland, also a member of the endocrine system, which in turn promotes the production of thyroxine. Thyroxine is responsible for controlling the body's metabolic rate, and therefore responsible for the amount of energy consumed and the volume of proteins produced.

PROPERTIES OF HORMONES:

Hormones are responsible to a great extent for either acceleration or retardation of enzyme action and its production. In this manner hormones regulate physiological activities through chemical co-ordination. Certain secretions 'Hormones' of this endocrine glands are conducted through the circulating blood. The glands which produce such secretions do not possess ducts, hence the endocrine glands are also called ductless glands. A hormone belonging to the individual of one species may be similar to the corresponding hormone of the individual of other species. This is a special characteristic of hormones.

CLASSIFICATION OF HORMONES

Hormones are classified into various types on the basis of their chemical structure as under:
(1)  Steroid Hormones: Estrogen, Progesterone, Aldesterone, Cortisone etc.

(2)  Biogenic Amines Hormones: Adrenaline, Noradenaline, Acetylchloline etc.

(3)  Peptide/Protein Hormones:Thyroxine, Glucagon, Insulin, Thyrotropin, Gonadotropins,
     Adrenocorticotropin,

     Parathormone etc.

Hormones are secreted in very small amounts. Hormones are chemicals which help in the regulation of various physiological activities like metabolism, growth, reproduction, metamorphoris, ecdysis or moulting, formation of pigment granules and osmoregulation in the body. The regulatory functions of the endocrine system are observed to be controlled either directly or indirectly. In animals it has been observed that the central nervous system influence the hormones regulating the color changes of the skin.

The secretion of gastric hormones are stimulated:
(i)  Under the influence of the nervous system and the (ii) local biochemical variations in the organs.
These gastric hormones regulate the secretion of the digestive enzymes.