Identification of prolactin and growth hormone cells in the pars distalis of the California leaf‐nosed bat, Macrotus californicus

Prolactin (PRL) and growth hormone (GH) cells were immunostained in the anterior pituitary lobe of the California leaf-nosed bat with antisera against rat PRL and GH by the unlabeled immunoperoxidase technique. The PRL antiserum reacts with a cell that is carmoisinophilic and pleomorphic and occurs in small groups within the ventro-, dorsocentral, and posteriolateral regions of the pars distalis. The cells that stain with the anti-GH serum are orangeophilic, smaller than the PRL cells, and randomly scattered throughout the pars distalis, singly or in palisades near capillaries. Morphometric analysis of the immunoreactive PRL and GH cells revealed an inverse relationship between these two cell types.