Question

The hormone secreted by the kidney is
(a)Gastrin
(b)Secretin
(c)Erythropoietin
(d)Aldosterone

Answer 1

Hint: The hormone that the kidney secretes is also called hematopoietin. It promotes the development in the bone marrow of red blood cells. It has a glycosylated structure ( 40% of the total molecular weight), having a half-life that is around five hours in the blood.

Complete answer:
-Three types of hormones are secreted by kidneys. They are erythropoietin, renin, and calcitriol.
-Peptide hormones secreted by the juxtaglomerular cells of the kidney are erythropoietin and renin.
-Calcitriol is a steroid hormone that is synthesized by nephron proximal tubule cells.
The type of molecule erythropoietin is a glycoprotein. In order to increase red blood cell development, it acts on the bone marrow. The release of this hormone is triggered by stimuli like bleeding or moving to high altitudes (where oxygen is scarcer).
The close association of peritubular capillary and proximal convoluted tubules results in erythropoietin in the kidney via the interstitial fibroblasts. It is also formed in the liver's perisinusoidal cells. In the fetal and perinatal phase, liver production is predominant; in adulthood, renal production predominates. Thrombopoietin is homologous to it.

Additional Information:
Gastrin is a peptide hormone that activates the parietal cells of the stomach to secrete gastric acid (HCl) and helps with gastric motility. G cells in the pyloric antrum of the stomach, duodenum, and pancreas release it.
By controlling secretions in the stomach, pancreas, and liver, secretion is a hormone that controls water homeostasis in the body and affects the duodenum environment. It is a peptide hormone formed in the duodenum's S cells located in the glands of the intestines.
The principal mineralocorticoid hormone, aldosterone, is a steroid hormone released in the adrenal gland by the zona glomerulosa of the adrenal cortex. In the kidney, salivary glands, sweat glands, and colon, it is important for sodium conservation.
So, the correct answer is, ‘Erythropoietin’.

Note: It is possible to keep people with failing kidneys alive by dialysis. Without a source of erythropoietin, anemia affects these patients. Now, recombinant human erythropoietin is available to treat these patients due to recombinant DNA technology.
It is also synthesized in mice that have been rendered anemic by osteoblasts; there is a lack of oxygen in the brain (e.g. after a stroke) and helps protect neurons from damage.
Probably recombinant human erythropoietin would also prove beneficial for victims of stroke.