Endocrine System

The endocrine system involves the endocrine glands, the hormones, and the different
mechanisms involved in the secretion and regulation of the hormones. Endocrinology is the
study of the endocrine system involving endocrine glands- hypothalamus, pituitary, thyroid,
adrenal and gonads, metabolic diseases, and nutritional medicine. Hormones that are produced
and secreted by the endocrine glands are controlled by highly regulated pathways, for instance,
the hypothalamic-pituitary axis, which, when disrupted, can result in the development of
endocrine disorders. The hormones are endogenous messengers that are responsible for signal
transduction and influence the function and metabolic rate of other cells and organs in the body.

Feedback Control Mechanisms

Feedback control mechanisms control the process of hormone secretion and comprise
positive and negative feedback mechanisms. In a negative feedback mechanism, hormone
secretion by the endocrine gland suppresses the release of stimulating or releasing hormones
from the hypothalamus or pituitary glands. For example, increased levels of thyroid hormone
induce signaling to reduce the release of thyrotropin-releasing and thyrotropin-stimulating
hormones. In a positive feedback mechanism, the secretion of a particular hormone enhances the
production and release of the hormone; for example, in uterine contractions during childbirth or
labor under the influence of oxytocin triggers the production and release of more oxytocin from
the posterior pituitary (Subramanian, 2021). These two mechanisms work together to control and
regulate hormones in the body.

Insulin

An endocrine hormone produced by the beta-cells of the pancreatic islets. It is the main
anabolic hormone in the body and is involved in the metabolism of carbohydrates, proteins, and

ENDOCRINE SYSTEM 3
fat by enhancing the absorption of glucose from the blood into the liver, fat tissue, and skeletal
muscles. It is involved in the reduction and regulation of serum blood sugar levels (Qaid et al.,
2016)

ENDOCRINE SYSTEM 4

References

Qaid, M. M., & Abdelrahman, M. M. (2016). Role of insulin and other related hormones in
energy metabolism—A review. Cogent Food & Agriculture, 2(1), 1267691.
Subramanian, U. (2021). Hypothalamic and Pituitary Hormones. In Introduction to Basics of
Pharmacology and Toxicology (pp. 633-652). Springer, Singapore.