Endocrine physiology: Identify the primary cardiovascular effect increased by norepinephrine (noradrenaline). Full question: Norepinephrine increases which parameter most prominently via α₁-mediated vasoconstriction? Choose the correct option.

Given data

• Hormone/neurotransmitter: Norepinephrine.

Concept / Approach
Norepinephrine predominantly stimulates α₁-adrenergic receptors in vascular smooth muscle → vasoconstriction → ↑ total peripheral resistance → ↑ blood pressure. It can also increase heart rate via β₁, but baroreflex may blunt HR; the hallmark effect is raised BP.

Eliminating distractors
Parasympathetic tone increases GI motility, not NE. NE does not directly increase GFR/urine output; intense vasoconstriction can reduce renal flow. Thermoregulation and pure HR-only effects are not the primary signature.

Final Answer
Blood pressure (via increased peripheral vascular resistance).