Alkaline Phosphatase Concentration in Cervical Mucus**This study was supported by National Institute of Health Grant T1AM 05428-06, and was presented in part at the Pacific Coast Fertility Society's 16th Annual Meeting, Palm Springs, California, November 1968

Current status of N-, O-, S-heterocycles as potential alkaline phosphatase inhibitors: a medicinal chemistry overview

Heterocycles are a class of compounds that have been found to be potent inhibitors of alkaline phosphatase (AP), an enzyme that plays a critical role in various physiological processes such as bone metabolism, cell growth and differentiation, and has been linked to several diseases such as cancer and osteoporosis. AP is a widely distributed enzyme, and its inhibition has been considered as a therapeutic strategy for the treatment of these diseases. Heterocyclic compounds have been found to inhibit AP by binding to the active site of the enzyme, thereby inhibiting its activity. Heterocyclic compounds such as imidazoles, pyrazoles, and pyridines have been found to be potent AP inhibitors and have been studied as potential therapeutics for the treatment of cancer, osteoporosis, and other diseases. However, the development of more potent and selective inhibitors that can be used as therapeutics for the treatment of various diseases is an ongoing area of research. Additionally, the study of the mechanism of action of heterocyclic AP inhibitors is an ongoing area of research, which could lead to the identification of new targets and new therapeutic strategies. The enzyme known as AP has various physiological functions and is present in multiple tissues and organs throughout the body. This article presents an overview of the different types of AP isoforms, their distribution, and physiological roles. It also discusses the structure and mechanism of AP, including the hydrolysis of phosphate groups. Furthermore, the importance of AP as a clinical marker for liver disease, bone disorders, and cancer is emphasized, as well as its use in the diagnosis of rare inherited disorders such as hypophosphatasia. The potential therapeutic applications of AP inhibitors for different diseases are also explored. The objective of this literature review is to examine the function of alkaline phosphatase in various physiological conditions and diseases, as well as analyze the structure-activity relationships of recently reported inhibitors. The present review summarizes the structure-activity relationship (SAR) of various heterocyclic compounds as AP inhibitors. The SAR studies of these compounds have revealed that the presence of a heterocyclic ring, particularly a pyridine, pyrimidine, or pyrazole ring, in the molecule is essential for inhibitory activity. Additionally, the substitution pattern and stereochemistry of the heterocyclic ring also play a crucial role in determining the potency of the inhibitor.

Size shifting of solid lipid nanoparticle system triggered by alkaline phosphatase for site specific mucosal drug delivery

We aim to prepare a size-shifting nanocarrier for site-targeting mucosal drug delivery that can penetrate through mucus gel layer and remain close to the absorption membrane. As nanocarriers can be engineered to penetrate mucus but they can also back diffuse into outer mucus regions, a size shifting to micron range once they have reached the absorption membrane would prevent back-diffusion effect and extend drug release over a long period of time. For this purpose, we loaded solid lipid nanoparticles (SLN) with a phosphate ester surfactant and octadecylamine. Alkaline phosphatase (AP), a membrane bound enzyme was for the first time utilized as an in situ partner for triggering the size conversion at epithelial cell surface. Having the size of ~120 nm, SLN with hydrophilic and phosphate-decorated shells were shown to penetrate through mucus gel and form aggregates above cell layer surface. Aggregates of 5-8 µm were formed due to interparticle interactions induced by enzymatic phosphate removal after ~30 min in contact with isolated AP. The developed SLN system could be a potential tool for mucosal drug delivery to AP-expressing tissues like colon, lung, cervix, vagina and some mucus-secreting tumors.

Oxytocin-induced biochemical changes in cervical mucus of the goat

This study was conducted to investigate the effects of oxytocin administration on plasma progesterone concentration and cervical mucus content of protein and acid and alkaline phosphatase activity in the goat. Oxytocin administered to goats (100 IU, S.C. daily) between Days 3 and 6 of estrous cycle induced estrus and resulted in a corresponding decrease in the levels of plasma progesterone, as well as in the contents of protein and in acid and alkaline phosphatase in the cervical mucus. Administration of indomethacin (10 mg/kg body weight, S.C.) inhibited oxytocin-induced estrus and changes in progesterone, protein and enzymes. It is suggested that oxytocin-induced changes are mediated via the production and release of prostaglandin F2alpha (PGF2alpha).

Sialo proteins and phosphatases in estrual cervical mucus of fertile and repeat breeder buffaloes ()

Concentrations of sialic acid and protein and activities of acid phosphatase (ACP) and alkaline phosphatase (AKP) were determined in estrual cervical mucus of fertile and repeat breeder buffaloes during late estrus. Significantly (P < 0.01) higher concentrations of sialic acid and ACP and AKP activities were observed in fertile buffaloes as compared with repeat breeder buffaloes. However, differences were nonsignificant in protein content between fertile and repeat breeder buffaloes, albeit protein concentration was higher in fertile buffaloes. The significance of sialoproteins and phosphatases in fertility has been clarified.

Ultrastructural localization of glucose-6-phosphatase and alkaline phosphatase in the vaginal epithelium of rat

The effect of ovarian hormones on the activities of glucose-6-phosphatase and alkaline phosphatase in the vaginal epithelium was studied in immature and ovariectomized rats, using ultracytochemical techniques. Comparative studies were done on normal rats at the luteal phase and on day 14 of pregnancy. Various vaginal cells show different degrees of response to progesterone and diethylstilbestrol (DES) with regard to glucose-6-phosphatase activity. Intense glucose-6-phosphatase activity was observed in the cisternae of granular endoplasmic reticulum (rER), Golgi saccules and vesicles, and nuclear envelope of both basal cells and stromal cells of progesterone treated rats, whereas in the basal cells and stromal cells of DES-treated and control animals the enzyme was totally lacking. Detectable glucose-6-phosphatase activity was also observed, however, in the rER cisternae and Golgi complex of keratohyalin-secreting squamous intermediate cells of the vaginal epithelium of DES-treated rats. Alkaline phosphatase was also found on the limiting membranes of secretory granules of mucocytes in animals at the luteal phase and during pregnancy. DES and progesterone in the doses used did not affect alkaline phosphatase activity in the rat vagina. Overall, progesterone enhances glucose-6-phosphatase activity in basal cells of the rat vagina prior to completion of mucification. Alkaline phosphatase was found in all cells involved in mucin secretion.

Lactate dehydrogenase in human cervical mucus: correlation with ovulation, influence of ovarian steroid hormones, and isozyme pattern

The glycolytic enzymes, lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase, and hexokinase in cervical mucus of 96 ovulatory women were serially measured daily during the menstrual cycle. Among all of the enzymes, the cyclic changes in LDH activity were the most significant, being high during the proliferative phase, gradually decreasing to the lowest level around ovulation, and then increasing markedly again. Estrogen inhibited cervical mucus LDH activity; progestrone accelerated it. Examination of the LDH isozyme pattern showed that H-LDH (H-subunit of LDH), being predominant throughout the cycle, apparently carries some responsibility for the cyclic change in LDH activity. In a comparison of LDH activity with the serum luteinizing hormone (LH) peak, the activity level nadir of LDH usually appeared between 1 day before and 1 day after the serum LH peak, pointing to the advantage of daily measurement of cervical mucus LDH activity for predicting the potential day of conception.

Cyclic changes of cervical mucus enzymes related to the time of ovulation. I. Alkaline phosphatase

The concentration of alkaline phosphatase in cervical mucus was serially determined during a menstrual cycle in five normal ovulatory women and correlated with the time of ovulation as monitored by the basal body temperature and radioimmunoassay of serum lutenizing hormone (LH), progesterone, and estradiol. The activity of alkaline phosphatase decreased significantly at midcycle just prior to the LH surge and began to rise after ovulation. Self-detection of cervical mucus alkaline phosphatase may provide a practical method of ovulation prediction.