Which of the following is not contained in the buffy coat?

A. It acts on the hypothalamus to decrease appetite: Appetite regulation is linked to hormones like leptin and ghrelin, not ADH.
B. It causes the release of hormones from the adrenal cortex: ACTH from the anterior pituitary does this, not ADH.
C. It causes smooth muscle contraction in the female reproductive tract: Oxytocin is responsible for uterine contractions, not ADH.
D. It causes vasodilation: ADH (vasopressin) actually causes vasoconstriction, not vasodilation.
E. It increases water retention from renal tubules: ADH acts on the collecting ducts of the kidney to promote water reabsorption, reducing urine output and conserving body water.

A. adrenal medulla; epinephrine: The adrenal medulla secretes epinephrine (and norepinephrine) for fight-or-flight effects (heart rate, glycogenolysis); it is not the main hormone that promotes Na⁺ and water retention.
B. pancreas; cortisol: The pancreas secretes insulin and glucagon, not cortisol; cortisol is produced by the adrenal cortex and has limited mineralocorticoid activity but is not the principal Na⁺/water-retaining hormone.
C. kidneys: corticosterone: The kidneys do not secrete corticosterone; corticosterone is an adrenal steroid (minor mineralocorticoid in some species).
D. adrenal cortex, aldosterone: Aldosterone (zona glomerulosa of the adrenal cortex) increases Na⁺ reabsorption and water retention and promotes K⁺ excretion in the kidney.
E. thyroid: calcitonin: Calcitonin from the thyroid lowers blood Ca²⁺ and has no role in Na⁺/water retention.