The metabolism of carbohydrate is controlled by hormones secreted by the endocrine glands, of which the pancreas, the anterior pituitary lobe and adrenal cortex appear to be of major importance.
1. Pancreas:
Islets of Langerhans of pancreas secrete a hormone what is known as insulin. Insulin was first of all obtained by Banting Best and Macleod in the year of 1921.
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Opinions differ about the mechanism of insulin control of carbohydrate metabolism. It is believed that it aids in the conversion of sugar to glycogen and in the utilization of sugar with the formation of the intermediate products of its metabolism.
Some say that it simply accelerates carbohydrate oxidation, while others regard its function as primarily concerned with the synthesis of carbohydrate from non-carbohydrate precursors or possibly with the conversion of carbohydrate to fat.
2. Anterior pituitary lobe:
According to Houssay the growth hormone and to some extent the adrenocorticotrophic and thyroid stimulating hormone control the carbohydrate metabolism as they are diabetogenic.
Growth hormone mobilises free fatty acids from the adipose tissue and thus favours ketogenesis. It also causes secretion of blood glucose elevating factor from the pancreas other than glucagon.
3. Adrenal cortex:
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The hormones produced by the cortical part of the adrenal gland also influence carbohydrate metabolism (according to long 4hd Lukens).
Recent findings state that besides these glands there are other glands which also regulate the carbohydrate metabolism.
These are thyroid glands which secrete thyroxine which not only increases the rate of absorption of carbohydrates from the intestine but also brings about increase in the rate of metabolism of carbohydrates.
The functions of these glands are under the control of the nervous system which, in the final analysis, regulates the entire carbohydrate metabolism.