Active uptake of sodium is promoted by action of enzyme known as

The correct option is aldosterone.

Step-by-Step Explanation:

1. Understanding the Physiological Process:
Active uptake (reabsorption) of sodium (${\mathrm{Na}}^{+}$) in the kidneys is crucial for maintaining blood pressure, fluid volume, and electrolyte balance in the body. This process primarily takes place in the distal convoluted tubules and collecting ducts of the nephrons.

2. Role of Aldosterone:
Aldosterone is a steroid hormone produced by the outer section (cortex) of the adrenal glands. It functions by binding to mineralocorticoid receptors in the epithelial cells of the renal collecting ducts. This binding stimulates the transcription and synthesis of basolateral sodium-potassium pumps (${\mathrm{Na}}^{+}/K^{+}$-ATPase) and apical sodium channels (ENaC).

3. Mechanism of Action:
The increase in these channels and pumps allows sodium ions to be actively transported from the tubular fluid back into the blood, while potassium ions are excreted. Therefore, aldosterone is the key hormone/enzyme-like signaling agent that directly promotes the active uptake of sodium.

4. Evaluating Other Options:
- Adrenatrone: This is not a standard physiological hormone or enzyme involved in sodium uptake.
- Antidiuretic hormone (ADH / Vasopressin): Primarily promotes the reabsorption of water, not the active uptake of sodium directly.
- Diuretic: Diuretics are substances or drugs that promote the excretion of water and salts (including sodium) in urine, which is the opposite of sodium uptake.