Inadequate hormone release is called hyposecretion.
It can result from.

Choice D rationale

Prolactin is a hormone secreted by the anterior pituitary gland, not the hypothalamus. Its primary function is to stimulate milk production in the mammary glands after childbirth. The hypothalamus produces prolactin-inhibiting hormone (dopamine) and prolactin-releasing factors that regulate prolactin secretion.

Choice A rationale

Antidiuretic hormone (ADH), also known as vasopressin, is synthesized in the hypothalamus and then transported to the posterior pituitary for storage and release. It plays a critical role in water reabsorption by the kidneys, regulating fluid balance and blood pressure.

Choice B rationale

Oxytocin is synthesized in the hypothalamus and subsequently stored and released from the posterior pituitary gland. It is involved in uterine contractions during childbirth and milk ejection during lactation, also playing a role in social bonding.

Choice C rationale

Growth hormone-releasing hormone (GHRH) is a hypothalamic hormone that stimulates the anterior pituitary to secrete growth hormone (GH). GHRH is crucial for regulating body growth and metabolism by promoting the release of GH.

Choice A rationale

During exercise, local accumulation of metabolic byproducts like lactic acid, carbon dioxide, and adenosine in active muscles causes vasodilation, not constriction, of precapillary sphincters and arterioles. This vasodilation increases blood flow to meet the increased metabolic demand.

Choice B rationale

During exercise, the adrenal medulla releases epinephrine and norepinephrine, and sympathetic nerves release norepinephrine. These catecholamines cause widespread vasoconstriction in inactive tissues but induce vasodilation in skeletal muscles through specific receptor activation (beta-2 adrenergic receptors), increasing blood flow to working muscles.

Choice C rationale

Muscle contraction does compress blood vessels, aiding venous return (skeletal muscle pump). However, this is a mechanical action aiding circulation, not the direct effect of adrenal medulla and sympathetic nerves on arteriolar diameter in response to exercise, which primarily involves neurochemical regulation.

Choice D rationale

During exercise, the sympathetic nervous system is highly activated, leading to a "fight or flight" response. Conversely, the parasympathetic nervous system, which promotes "rest and digest" functions, is generally inhibited or its activity is decreased, not activated, to allow for increased cardiac output and blood flow to muscles.