MELANOCYTE-STIMULATING ACTIVITY IN SERUM AND THE AQUEOUS FLARE RESPONSE IN RABBITS

Abstract
A number of extra-pigmentary effects have been found to occur after injection of melanocyte-stimulating hormone (MSH) in mammals (Kastin, Kullander, Borglin, Dahlberg, Dyster-Aas, Krakau, Ingvar,Miller, Bowers & Schally, 1968). In the rabbit's eye, the blood-aqueous humour barrier is transitorily damaged leading to leakage of serum proteins into the aqueous humour (Dyster-Aas & Krakau, 1964; Dyster-Aas, 1965). This increase in protein can be visualized and measured by the Tyndall effect (Dyster-Aas & Krakau, 1963). It seems that the flare-inducing effects of MSH are elicited indirectly, the inter-mediate step being the release or activation of a serum factor. The question was raised whether this serum factor could be MSH attached to some carrier protein or whether a new factor had been formed (Dyster-Aas & Krakau, 1966). The latter view was indirectly supported by recent experiments in which exogenous MSH could be excluded as the direct cause (Dyster-Aas & Krakau, 1968). However, involvement