Give an account of chemical nature and function of Neurohypophyseal hormones in mammals. (IFS 2021/15 Marks)
Give an account of chemical nature and function of Neurohypophyseal hormones in mammals. (IFS 2021/15 Marks)
Introduction
Neurohypophyseal hormones, also known as posterior pituitary hormones, are produced in the hypothalamus and stored in the posterior pituitary gland. The two main neurohypophyseal hormones in mammals are oxytocin and vasopressin (also known as antidiuretic hormone). These hormones play crucial roles in various physiological processes in mammals.
Chemical Nature of Neurohypophyseal Hormones
- Oxytocin
- Structure: A nonapeptide composed of nine amino acids.
- Synthesis: Produced in the paraventricular nucleus of the hypothalamus.
- Transport and Storage: Transports along the hypothalamo-neurohypophysial tract to the posterior pituitary, where it is stored until release.
- Vasopressin (Antidiuretic Hormone, ADH)
- Structure: Also a nonapeptide with nine amino acids.
- Synthesis: Synthesized in the supraoptic nucleus of the hypothalamus.
- Transport and Storage: Moves via the hypothalamo-neurohypophysial tract to the posterior pituitary for storage.
Functions of Neurohypophyseal Hormones
- Oxytocin
- Uterine Contraction: Stimulates smooth muscle contractions during labor, facilitating childbirth.
- Lactation: Promotes milk ejection from mammary glands during breastfeeding.
- Social and Behavioral Roles: Influences social bonding, maternal behaviors, and emotional responses.
- Vasopressin (ADH)
- Water Balance: Regulates water retention by the kidneys, reducing urine output to conserve body water.
- Vasoconstriction: Causes constriction of blood vessels, aiding in the regulation of blood pressure.
- Social and Behavioral Roles: Affects social behaviors and stress responses.
Conclusion
Neurohypophyseal hormones, oxytocin, and vasopressin play essential roles in various physiological processes in mammals. Oxytocin is involved in uterine contractions, milk ejection, social bonding, and emotional regulation, while vasopressin regulates water balance, blood pressure, and social behaviors.