Binding characteristics of inhibin in rat ventral prostate

Abstract

Homogeneous preparation of human seminal plasma inhibin (molecular weight 13,500) was iodinated with 125I to a specific activity of about 40-45 microCi/micrograms and tested for binding to a rat prostate crude membrane preparation. The binding of inhibin was a saturable process as well as time and temperature dependent. This binding was displaceable in a dose-dependent manner by unlabelled inhibin. Other hormones such as LH, FSH, Prl, and TSH from rat or human origin did not influence the binding of labelled inhibin to rat prostate membrane. Of various age groups of rats studied, the maximum binding was observed in 75-day-old rats. The radiolabelled inhibin also showed specific binding to rat pituitary. The preliminary studies regarding involvement of steroids in the control of inhibin receptors in prostate and pituitary indicated that testosterone activates the inhibin receptors at the prostatic level whereas estradiol did not have any effect. However, estradiol increases the pituitary receptors for inhibin as compared to testosterone.

The Cotton-Top Tamarin (Saguinus oedipus) Has Five β-Microseminoprotein Genes, Two of Which Are Pseudogenes

“…MSP has also been suggested to be the major immunoglobulinbinding protein in semen (Liang et al, 1991;Kamada et al, 1998). Several studies have indicated binding sites for MSP in different tissues and cells (Phadke et al, 1982;Vanage and Sheth, 1982;Dandekar et al, 1983;Yang et al, 1998). Recently, a binding protein, denoted PSP94-binding protein (PSPBP), was purified from human serum, and PSPBP-mRNA was detected in blood leucocytes, prostate, testis, ovary, and intestine (Reeves et al, 2005).…”

Structural and molecular biology of PSP94 Its significance in prostate pathophysiology

“…Further observation showed that PSP94 levels are significantly lower in tissue of PCa patients as compared to BPH patients and healthy men (15). Early studies have indicated PSP94 to exist as a bound form in serum (16,17) and at the cell surface of pituitary, prostate and sperm (18,19,20). The identification and characterization of proteins interacting with PSP94 has been the subject of numerous research studies to understand the biology behind the many reported functions of PSP94.…”

“…PSP94 exists as a monomer which consists of two domains held together by the disulfide linkage between Cys37-Cys73; where the N-(residues 1-52) and Cterminal (residues 53-94) are held in close proximity via a strong hydrogen bond (106). The ten cysteine residues were found to be paired between 2 Cys-50 Cys, 18 Cys-42 Cys, 37 Cys- 73 Cys, 40 Cys-49 Cys and 64 Cys- 87 Cys (Figure 2). The disulphide alignments of beta-MSPs from different species obtained by means of different methods are compared in Table 2.…”