Sweating in the intact ox and isolated perfused ox skin

1. Heated, intact oxen discharged sweat as a steady continuous output rising abruptly and synchronously approximately every 5 min. 2. I.V. adrenaline (Adr) or large doses of phenylephrine (PhE) induced sweating but isoprenaline (Isop) did not. 3. In isolated perfused skin, alpha-adrenergic drugs induced sweating which was blocked by phentolamine. 4. Vasodilator drugs reduced the sweat output induced by Adr, whereas the beta-antagonist propranolol increased it. These effects were possibly due to microvascular changes. 5. Natural fluctuations in sweat rate seem likely to be due to contraction of sweat gland myoepithelium, but it is uncertain whether myoepithelial contraction was ever induced by drugs.