The effect of isoprenaline and pilocarpine on (a) bronchial mucus-secreting tissue and (b) pancreas, salivary glands, heart, thymus, liver and spleen.

The effect was followed in the rat of 6 or 12 injections of isoprenaline (IPN), at a dose of 10 or 25 mg, and pilocarpine (PCP) at a dose of 10 mg. In some respects the effects are similar, in others strikingly dissimilar. IPN and PCP each increase bronchial submucosal gland size and the number of goblet cells previously thought not to be under nervous control. Isoprenaline increases goblet cells containing acid glycoprotein, the PCP all types: IPN increases small acini in the gland, PCP large ones. The IPN effect was apparent even under germ-free conditions. After 12 injections of PCP the secretory cells appeared “exhausted” and relatively empty of secretion. A similar picture was seen in the pancreas and the salivary glands—hypertrophy after IPN or 6 injections of PCP, exhaustion after 12 of PCP. In the heart, IPN caused an increase in ventricular weight (the right more affected than the left), increase in fibre size and a minor degree of myocardial damage; PCP caused only dilatation. After 6 injections, both IPN and PCP reduced thymic weight; this had recovered after 12 injections. The effect of PCP seems to be at least in part directly on discharge; IPN seems to affect synthesis. This is the first demonstration of goblet cell increase by drug effect. These changes are considered in relation to control of mucus secretion and to their relevance to cystic fibrosis.