Immunohistological distribution of the secretory endometrial protein, ‘pregnancy-associated endometrial α2-globulin’, a glycosylated β-lactoglobulin homologue, in the human fetus and adult employing monoclonal antibodies

Abstract

We have previously demonstrated that pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), the human glycosylated beta-lactoglobulin homologue (HG-BLG), is quantitatively the major secretory soluble protein product of the secretory endometrium during the latter half of the menstrual cycle and decidua spongiosa of the gestational endometrium during early pregnancy, and is principally localized to the glandular epithelium. In the present study employing monoclonal antibodies in immunohistological techniques, the distribution and localization has been examined in normal and pathological tissues of the adult and first-trimester fetus. No significant staining for alpha 2-PEG was detected in any non-reproduction-associated tissue in the normal adult nor any tissue in the fetus. In the adult, most intense staining was associated with the endometrial glandular epithelium in the uterus or in ectopic sites in patients with endometriosis. During the menstrual cycle and pregnancy, appearance of alpha 2-PEG in endometriosis was strongly linked with its appearance in uterine endometrial tissue, suggesting that endometriotic tissue exhibited competence to respond to the same hormonal milieu required to induce synthesis in the uterine endometrium. Localization to the mucosal epithelium of the Fallopian tube was consistent with synthesis of alpha 2-PEG, albeit at low levels, and staining at this site reflected fluctuations of staining within the uterus. Of the pathological specimens examined, staining was only detected in a proportion of ovarian carcinomas. No staining was detected in the mammary gland, a site of beta-lactoglobulin synthesis, whether obtained during pregnancy or lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycodelins as regulators of early events of reproduction

“…As in normal endometrium, endometriosis lesions contain GdA (Cornillie et al, 1991;Waites et al, 1990), but the cyclical GdA expression in endometriosis tissue is more irregular. Even at midcycle where serum GdA levels normally reach a nadir they can be elevated in patients with stage III-IV endometriosis Julkunen et al, 1985;1986a,b).…”

Evidence of Juxtacrine Signaling for Transforming Growth Factor α inHuman Endometrium1

“…To date, we are aware of no published report of TGF␣ in human intraluminal fluid. By way of comparison, a protein known to be secreted by the endometrium into the luminal fluid, namely pregnancy-associated endometrial ␣-2 -globulin, has been demonstrated in intraluminal fluid at a concentration of 2-4 g/ml [24]. This protein concentration is 200 000-to 400 000-fold in excess of the detection limits of our assay.…”