Glycodelin, also known as placental protein 14 (PP14) or progesterone-associated endometrial protein (PAEP), is a human glycoprotein with potent immunosuppressive and contraceptive activities. In this paper we report the first characterization of glycodelin-derived oligosaccharides. Using strategies based upon fast atom bombardment and electrospray mass spectrometry we have established that glycodelin is glycosylated at Asn-28 and Asn-63. The Asn-28 site carries high mannose, hybrid and complex-type structures, whereas the second site is exclusively occupied by complex-type glycans. The major non-reducing epitopes in the complextype glycans are: Gal␤1-4GlcNAc (lacNAc), GalNAc␤1-4GlcNAc (lacdiNAc), NeuAc␣2-6Gal␤1-4GlcNAc (sialylated lacNAc), NeuAc␣2-6GalNAc␤1-4GlcNAc (sialylated lacdiNAc), Gal␤1-4(Fuc␣1-3)GlcNAc (Lewis x ), and GalNAc␤1-4(Fuc␣1-3)GlcNAc (lacdiNAc analogue of Lewis x ). It is possible that the oligosaccharides bearing sialylated lacNAc or lacdiNAc antennae may manifest immunosuppressive effects by specifically blocking adhesive and activation-related events mediated by CD22, the human B cell associated receptor. Oligosaccharides with fucosylated lacdiNAc antennae have previously been shown to potently block selectin-mediated adhesions and may perform the same function in glycodelin. The potent inhibitory effect of glycodelin on initial human sperm-zona pellucida binding is consistent with our previous suggestion that this cell adhesion event requires a selectin-like adhesion process. This result also raises the possibility that a convergence between immune and gamete recognition processes may have occurred in the types of carbohydrate ligands recognized in the human.

The serum levels of 34K insulin-like growth factor (IGF)-binding protein were measured by RIA in 88 type 1 diabetic patients, 9 patients with type 2 diabetes, 7 patients with insulinoma, 19 normal subjects (all after an overnight fast), and 82 normal subjects after a breakfast meal. In addition, the effect of 2- to 3-h euglycemic steady state hyperinsulinemia on serum IGF-binding protein and IGF-1 levels was studied in some subjects in each of the fasted groups. Compared with normal subjects, the mean serum IGF-binding protein levels were 4-fold (P less than 0.001) higher in type I diabetic patients treated with conventional insulin injections, 2.5-fold (P less than 0.001) higher in those treated with continuous sc insulin infusion, and 2-fold (P less than 0.05) higher in patients with type 2 diabetes. In the patients with insulinoma, the mean IGF-binding protein level was 63% below normal (P less than 0.001), and it normalized after removal of the tumor. There was a slight negative correlation between the IGF-binding protein level and insulin dose in the diabetic patients (r = -0.22; P less than 0.05). In normal subjects, serum insulin concentrations were 2-fold higher (P less than 0.001) and the IGF-binding protein level was 29% lower after a meal (P less than 0.05) than in the fasting state. Serum IGF-I concentrations were virtually identical in the type 1 and 2 diabetic patients, insulinoma patients, and normal subjects. During steady state euglycemic hyperinsulinemia, the IGF-binding protein level fell by 40-70% in each group (P less than 0.001), whereas the IGF-I level declined (P less than 0.05) in the type 2 diabetic patients only. The decline of binding protein was closely related to the baseline level (r = 0.94; P less than 0.001). No correlation was found between serum IGF-I and binding protein levels in any group. In conclusion, 1) serum 34K IGF-binding protein levels are elevated in type 1 and 2 diabetic patients and decreased in patients with insulinoma; 2) the serum binding protein, but not IGF-I concentration is decreased by acute hyperinsulinemia; and 3) these data suggest that the serum insulin concentration plays a role in regulation of the serum 34K IGF-binding protein concentration.

The regulation of epithelial cell function and morphogenesis by the paracrine effectors from the mesenchyme or stroma has been well established using in-vivo studies. A more complete understanding of these relationships has been delayed due, in part, to a lack of appropriate co-culture models. In this study, we describe a co-culture model which demonstrates that normal paracrine relationships can be reconstituted in vitro and that human endometrial stromal cells regulate both growth and differentiation of primary human endometrial epithelial cells. Interesting differences in the proliferation of stromal and epithelial cells were noted in response to the basement membrane extract, Matrigel((R)). Exposure of stromal cells to Matrigel((R)) enhanced the paracrine capacity of these cells in vitro. When epithelial cells were co-cultured in contact with stromal cells embedded in Matrigel((R)), epithelial cell growth was inhibited by 65-80% compared to controls. Stromal cells in contact with Matrigel((R)) also regulated epithelial cell differentiation, as shown by induction of glycodelin expression. These co-culture studies show great promise as a method to investigate the cellular interactions between endometrial stromal and epithelial cells and their environment and to understand the molecular basis for the regulation of normal growth and differentiation of cells within complex tissues such as the endometrium.

We

We have recently demonstrated that a human amniotic fluid-derived glycoprotein, glycodelin-A (GdA; previously known as PP14 or PAEP), potently inhibits gamete binding in an established sperm-egg binding system and expresses immunosuppressive activities directed against a variety of different immune cell types. GdA has high mannose-, hybrid-, and complex-type biantennary oligosaccharides including structures with fucosylated or sialylated N,N-diacetyllactosediamine (GalNAc␤1-4GlcNAc) sequences, which are rare in other human glycoproteins. We now report the characterization of glycodelin-S (GdS). This is a human seminal plasma glycoprotein that is immunologically indistinguishable from GdA, but unlike the latter, does not inhibit human sperm-zona pellucida binding under hemizona assay conditions. Analysis of the N-glycans of GdS by mass spectrometry revealed that all glycoforms of GdS are different from those of GdA. GdS glycans are unusually fucose-rich, and the major complex-type structures are biantennary glycans with Lewis x (Gal␤1-4(Fuc␣1-3)GlcNAc) and Lewis y (Fuc␣1-2Gal␤1-4 (Fuc␣1-3)GlcNAc) antennae. It is probable that these highly fucosylated epitopes contribute to the immunosuppressive activity of human seminal plasma and to the low immunogenicity of sperm. This study provides the first evidence for gender-specific glycosylation that may serve to regulate key processes involved in human reproduction.