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Several different forms of the enzyme phospholipase C are present in uterine muscle. This was the conclusion of a study that isolated RNA from uterine tissue samples from rats and converted it to DNA using reverse transcriptase. DNA sequencing then revealed that five forms of phospholipase C were present: phospholipase C-beta1a, phospholipase C-beta3, phospholipase C-gamma1, phospholipase C-gamma2, and phospholipase C-delta1. The levels of these forms of the enzyme were higher in tissue samples from pregnant rats compared to non-pregnant rats.

Cytosolic phospholipase A2, an enzyme found in amniotic fluid, appears to play a role in the labor preparation process. It may also serve as a catalyst for the production and functioning of prostaglandins and arachidonic acid during labor. Cytosolic phospholipase A2 activity was determined in amniotic samples from six premature deliveries with labor, seven premature deliveries without labor, five deliveries with labor, and seven full-term deliveries without labor. Longer pregnancies had higher enzyme activity levels with the highest activity found in full-term samples without labor. Activity dropped significantly after labor.

Background. Recently, the authors reported that membrane-associated phospholipase [A.sub.2] (M-[PLA.sub.2]) was one of the acute phase reactants and increased in serum of patients with various malignant tumors. Methods. M-[PLA.sub.2] concentrations in tissue specimens from 78 breast cancers, 16 benign breast tumors, and 10 normal breast tissues were determined by a specific radioimmunoassay recently developed. Immunohistochemical staining was performed on all specimens by the avidin-biotin-peroxidase method. Results. Tissue levels of M-[PLA.sub.2] concentration were significantly higher in breast cancer than in benign breast tumor or normal breast tissue (P < 0.01). Correlation analyses between the tissue concentration of M-[PLA.sub.2] and clinicopathologic factors showed that tissue M-[PLA.sub.2] levels were significantly higher in patients with skin or muscle invasion, vessel involvement, and distant metastasis than in those without. In addition, this enzyme concentration was significantly greater in scirrhous carcinoma than in papillotubular or solid-tubular carcinoma. No association was found between M-[PLA.sub.2] concentration and steroid hormone receptor status. Immunohistochemically, M-[PLA.sub.2] was preferentially stained in the invading zone of breast cancer tissues, especially in scirrhous carcinoma. Patients with breast cancer with low levels of M-[PLA.sub.2] showed significantly longer overall survival and disease-free survival compared with those with high levels of this enzyme at the cutoff point of 50 ng/100 mg protein. The combination of estrogen receptor status with M-[PLA.sub.] concentration could be a powerful prognostic factor in predicting such survival rates. Conclusions. M-[PLA.sub.2] is closely related to the malignant potential of breast cancers, and the M-[PLA.sub.2] contents in breast cancer tissues could be a new valuable prognostic factor, other than the hormone receptor, in delineating the status of human breast cancer. Cancer 1993; 71:3058-64.

Attempts to discover the cause of menorrhagia, a menstrual disorder characterized by excessive bleeding, have not met with success, and women who suffer from this condition have hormonal levels that appear to be normal. One hypothesis concerning the origin of menorrhagia is that the uterine lining (endometrium) in such patients may produce abnormal levels of prostaglandins, substances associated with increased bleeding. Prostaglandins are manufactured from arachidonic acid, which, in turn, is made available as a result of the action of the enzymes phospholipase A2 (types 1 and 2) or phospholipase C. To learn more concerning the activities of these enzymes in menorrhagia, a study was carried out of uterine biopsy specimens from patients with menorrhagia and a control group of women who underwent other gynecologic surgery (sterilization or tubal surgery). Results showed that, in both groups, the activities of phospholipase A2 types 1 and 2 were higher during the secretory (pre-ovulatory) phase of the menstrual cycle than during the proliferative (pre-implantation) phase. Lower levels of activity of phospholipase A2 type 2 were seen in women with menorrhagia than in controls during the proliferative phase, and higher levels of phospholipase C were seen in menorrhagic subjects in both phases. The results suggest that women with menorrhagia may have defects of prostaglandin synthesis during the early phase of the menstrual cycle, causing defects in regeneration (regrowth) and repair of the uterine lining that result in excessive bleeding. A discussion is presented of the role of phospholipases in prostaglandin synthesis during the menstrual cycle. (Consumer Summary produced by Reliance Medical Information, Inc.)

Purpose: PLC plays a critical role in many intracellular processes such as growth, differentiation and transformation. There are three major classes of PLCs, namely PLC-Β, [Gamma] and Δ. PLC-[Gamma]1 is [...]

At present, there are no treatments known to reduce elevated levels of such 'emerging' lipid markers as lipoprotein (a) and lipoprotein-associated phospholipase [A.sub.2]--which is another compelling argument against routine measurement [...]

The PLAC Test has received Food and Drug Administration marketing clearance. The test measures the level of lipoprotein-associated phospholipase [A.sub.2]--an enzyme identified as a risk factor for coronary heart disease. [...]