Effects of epidermal growth factor and androgen influences on accessory sex glands in prepubertal Swiss-Webster mice

Immunohistochemical localization of the epidermal growth factor-receptor in rhesus-monkey prostate

Epidermal growth-factor receptor (EGF-r), a membrane-bound glycoprotein activated by EGF, is important in maintaining the integrity and function of the prostate. To investigate EGF-r presence in the prostate of the rhesus monkey, monoclonal-antibody immunohistochemical examination was performed. The monkey prostate consisted of the cranial and caudal lobes, and the prostatic epithelial cells were composed of the secretory and basal cells. The distribution patterns of EGF-r in the prostatic epithelial cells were quite different between the cranial and caudal lobes. In the caudal lobe, EGF-r was seen in both secretory and basal cells, whereas, in the cranial lobe, the EGF-r was seen exclusively in the basal cells. The stromal cells of both lobes did not show EGF-r. This study revealed that each prostatic lobe contains specific binding sites for EGF, indicating a biological difference between the two lobes of the prostate of the rhesus monkey.

Epidermal growth factor: receptor binding and effects on the sex accessory organs of sexually mature male mice

The role of epidermal growth factor (EGF) in maintaining the integrity of the male sex accessory glands was investigated in the mouse. In the sexually mature male C3H mouse, EGF levels were highest in the submandibular gland, followed by the seminal vesicles and the prostate. Twenty eight days after sialoadenectomy (Sx), EGF fell below detectable limits in the serum and in the seminal vesicles. However, the prostate still retained 22% of its immunoreactive EGF. There was a seven-fold increase in serum testosterone after sialoadenectomy. Despite this drastic rise in testosterone, both prostatic and seminal vesicular weights were reduced, serum levels of LH were suppressed only by 37% and FSH levels were not altered. All these changes were abolished by the simultaneous administration of exogenous EGF at 100 micrograms./kg./day for 28 days. Both prostatic and seminal vesicular membranes contained binding sites for 125I-EGF. Binding was maximal after one hour of incubation at room temperature. Two classes of binding sites were shown for either organ (Kd = 1.2 nM, n = 56 fmol/mg. and Kd = 74 nM, n = 540 fmol/mg. for prostate; Kd = 0.9 nM, n = 29 fmol/mg. and Kd = 93 nM, n = 150 fmol/mg. for seminal vesicle). The binding of 125I-EGF was displaced by excess EGF and TGF-alpha but not by insulin, ILGF-2 and PDGF. These data suggest that EGF may have an important role in maintaining the integrity of the seminal vesicle and the prostate in the mouse. While the seminal vesicle appears to acquire EGF by uptake from the environment, the prostate may have the ability to synthesize EGF locally.

Prostate plasma membrane receptor: a hypothesis

Based on 50 years of emerging knowledge about and changing views of prostate biochemistry and physiology and especially on the belief that there is an underlying mechanism of androgen control, the hypothesis is developed and tested that the rates of proliferation, biosynthesis, metabolism, and secretion are modulated through the hormone-sensitive Na, K-ATPase of the plasma membrane. These preliminary experiments, constituting a novel synthesis of technologies from endocrinology, intermediary metabolism, and membrane transport, attempt to explain the extraordinary production and secretion of citrate and how this may be coupled to sustaining prostate cell number and function. Attention is focused on learning where androgen is bound and how it interacts with the Na,K-ATPase. Both the dissimilar properties of epithelial and stromal cells in the separate regions of the acinus and the changing environment of growth factors in which these cells are bathed help account for their unlike reactivities during development and ongoing mature function. Little wonder that one hormone can have so many effects!