INTRODUCTION

Endocrinology is one of the most fascinating disciplines

of modern biology. It is the study of glands and the hormones

they produce. The secretions of these glands are

produced internally, hence the name endocrine in

comparison to secretions of other (exocrine) glands which

are secreted externally or in the lumen. The most exciting

aspect of endocrinology is its very minute secretions (hormones)

initiating a cascading effect on the target organs

and human metabolism affecting body systems, organs

and tissues locally as well as at varying distances from

the site of secretion. The hormones have local effects on

the cells which synthesize them (autocrine) as well as on

the immediate surroundings and adjacent cells (paracrine).