Effect of prolactin on short circuit current, potential and electrical resistance across isolated frog skin

The effect of a range of ovine prolactin doses (10(-9)-10(-6)M) on the short circuit current (Isc), potential difference (E) and electrical resistance (R) of isolated frog skin has been studied. Prolactin produced a dose dependent stimulation of Isc and generally a fall in R, although the latter was only significant after 10(-9) and 10(-6)M prolactin. The effect of prolactin on E was found to be more dependent upon the initial E (at the time of hormone addition) than on the dose of hormone. 10(-9)M prolactin, in contrast to higher doses, produced a sustained fall in R without stimulating Isc. Thus the effect of prolactin on frog skin appears to be predominantly on passive permeability at low doses, and on active ion transport at higher doses.