Receptor of prolactin and its effect on binding of corticotropin in human and guinea pig adrenocortical cells

Specific binding of prolactin (PRL) by human and guinea pig isolated adrenocortical cells is saturable and reach equilibrium during 60 min. Characteristics of PRL binding by adrenocortical microsomes were determined. A single receptor species related to the high affinity and low binding capacity receptor class was revealed. The PRL-receptor affinities in adrenal cortex and liver are similar (approximately 10(9) M-1). Human adrenals have a higher affinity than that in guinea pigs. PRL increased corticotropin binding by adrenocortical cells of both species. Corticotropin binding rise may be due to the increase in the number of available receptors of low affinity and high capacity.