Question

The first hormone to be isolated was:
A. Thyroxine
B. Testosterone
C. Epinephrine
D. Secretin

Answer 1

Hint: The first hormone to be isolated was Secretin, it was the first chemical messenger to be identified

Complete answer: In the year 1902, William Bayliss and Ernest Starling first discovered Secretin while they were studying how the process of digestion is controlled by the nervous system, during which they discovered an element secreted by the intestinal lining stimulates the pancreas which was after it was transported by the bloodstream and named it as ‘secretin’ further it was later isolated and sequenced by Jorpes and Mutt.
The first thyroid hormone to be isolated and crystallized was thyroxine in the year 1914.
In the year 1935 testosterone was isolated.
Epinephrine was isolated in the crystalline form before the testosterone was isolated.

Hence the correct option is ‘D’

Note: Secretin hormone influences the environment in the duodenum by regulating the secretion in the stomach, pancreas, and stomach.
They are located in the intestinal glands and are produced in the S cell of the pancreas.
They regulate the water homeostasis in the body.