Hyperadrenalism > Cushing’s syndrome, Hypertension, Hyperglycemia

2.   A 45 years old man with an endocrine disorder was found to have ‘moon face’

appearance, purple striae on the abdomen, hypertension and hyperglycemia.

2.1 What is the endocrine gland affected?  (10 marks)
2.2 List 3 hormones that are secreted by the gland mentioned in 2.1  (15 marks)
2.3 What is the probable endocrine disorder present in this patient?  (15 marks)
2.4 Explain the physiological basis for the following features seen in this patient.
 2.4.1 Hypertension  (30 marks)
 2.4.2 Hyperglycemia  (30 marks)

 Answers:

2

2.1  Adrenal gland (cortex)
2.2  mineralocorticoids – aldosterone
        Glucocorticoids – cortisol
        Androgens
2.3  hyperadrenalism>>>>>Cushing’s syndrome







2.4
2.4.1   Cushing’s syndrome is condition caused by hypersecretion of cortisol by adrenal cortex .
Hypertension is themain cardiovascular feature of the disease & is defined as a systolic blood
pressure over 140 mmHg and diastolic over 90 mmHg
Cortisol has a slight mineralocorticoid activity inphysiologicalnormal levels.This effect is
insignificant but in Cushing’s disease where there is excessive amounts of cortisol this effect
may be significant
Mineralocorticoids such as aldosterone act on principal cells of collecting ducts tubules &
distal tubules & stimulate the Na+/K+ATPase pump in the basolateral membrane . There by it
increases Na+ reabsorption & K+ secretion. When Na+ is reabsorbed it creates an osmotic
gradient from lumen to the blood . This will cause increased blood volume & there for preload
. According to frank starling law, the force of contraction will increase leading to increased
stroke volume & therefore increased cardiac out put.
Cortisol also acts to inhibit vasodilator production (ex- inhibition of nitric oxide synthase which
reduce the vasodilator nitric oxide )& increase intra cellular Ca2+ in the vascular smooth
muscles , promoting contraction.
Mean arterial pressure = cardiac out put * TPR
Since cardiac output & TPR both increase , the mean arterial pressure also rise giving rises to
hypertension

2.4.2  Hyperglycemia is excessive levels of glucose in blood. Cortisol has following effects on
metabolismof carbohydrates proteins & fats
Cortisol stimulate gluconeogenesis by formation of glucose from protein & other substances
increasing enzymes required to convert amino acid to glucose in liver & mobilization of amino acid
from extra hepatic tissues
It decreases the utilization of glucose by the cell by decreasing oxidation of NADH to NAD which is
necessary for glycolysis .
It also causes mobilization of fatty acids from adipose tissues & increase fatty acid oxidation which
leads to long term conservation of blood glucose & glycogen
The net effect these mechanism will be to increase blood glucose levels . Though the resulting high
levels of glucose in blood stimulates insulin secretion ,cortisol gives rise up to insulin resistance
which causes reduced insulin dependent uptake of glucose from muscle & adipose leading to
persistence levels of high blood glucose .
In Cushing’s syndrome hypersecretion of cortisol leads to extensive effects mention above giving
rise to very high blood glucose levels ,hyperglycaemia