Hypophysectomized and adrenalectomi z e d desoxycorticosterone-maintained rats were treated with prolactin during a period of 15 days. Acute polyarthritis developed between the 10th and 12th days in most adrenalectomized rats, whereas no such lesions could be evidenced in hypophysectomized animals. Prolactin, on the other hand, had no influence on the course of a croton-oil induced inflammation. The possible significance of these observations is discussed.Rattos mantenite, post hypophysectomia e adrenalectomia, per disoxycorticosterona esseva tractate con prolactina clurante un period0 de 15 dies. Polyarthritis acute se disveloppava inter le decime e le dece-secunde die in le majoritate del adrenalectomisate rattos, durante que nulle tal lesiones esseva manifeste in hypophysectomisate animales. Prolactina, del altere latere, habeva nulle influentia super le curso de un inflammation inducite per oleo de coton. Le signification possibile de iste observationes es discutite.E HAVE REPORTED previously that acute joint lesions develop W readily in adrenalectomized or hypophysectomized rats treated with both prolactin and growth hormone.'J When injected with prolactin alone, only a few animals show mild arthritic changes, which indicates that the concurrent administration of growth hormone definitely promotes the development of the lesions. However, no pathologic changes in the joints occur in animals treated with growth hormone alone under similar experimental conditions. In this regard, it should be mentioned that the growth hormone arthropathies reported by other workers3.* appear only after several months of treatment, and at that they are merely part of acromegalic manifestations found in chronically overdosed animals.Further to these observations, it was felt of interest to investigate whether higher doses of prolactin would induce arthritis in the absence of exogenous growth hormone. Our hypothesis was that the prolactin polyarthritis could develop only under a relative state of hypocorticoidism and that the presence of endogenous growth hormone was required. It was also necessary to ascertain whether prolactin would influence the course of an inflammatory reaction such as a granuloma pouch induced with croton oil.
METHODSOur experiments were carried out on female Sprague Dawley (Holtzman) rats weighing between 125 to 150 Gm. They were maintained on Pnrina Fox Chow diet and tap water ad libitum.The first experiment was made in adrenalectomized and hypophysectomized rats, the former receiving a maintenance dose of 1 mg. of desoxycorticosterone acetate (Ciba,
This work was supported b y a grant from the Canadian Arthritis and RheumathaThe prolactin used in this work was a gift from the Endocrinology Study Section, Society.
