Metal accumulation in juvenile and sub-adult loggerhead and green turtles in northern Cyprus.

Sea turtles are considered pollution bioindicators due to their tendency to accumulate high metal levels in their tissues during their long lifespans. In this context, we aimed to analyse the concentrations of 12 elements in liver, kidney, heart and muscle samples from green turtles (Chelonia mydas; n = 41) and loggerhead turtles (Caretta caretta; n = 14) found stranded in Northern Cyprus. The samples were collected between 2019 and 2021, stored in sterile Eppendorf tubes at -20 °C until metal analysis, and analysed with an inductively coupled plasma mass spectrometer. With this study, we contribute to the limited number of studies on metal accumulation in heart tissue and present the first data for Mg accumulation in the heart, liver, muscle and kidney tissues of both species. We found that metal accumulation levels differed among the two study species' tissues, with some elements in the same tissue (AlKidney, AsHeart, AsLiver, FeMuscle, FeKidney, FeHeart, MnHeart, PbHeart, ZnMuscle and ZnKidney) significantly differing between species. The observed variation likely resulted from their different feeding habits, which cause them to be exposed to different levels of metals. We also found significant associations among elements within tissues, as well as between the same element across different tissues in both species, which may indicate the differential accumulation of elements among organs due to physiological processes in turtle metabolism, bioaccumulation or excretion.

Molecular role of peptides/proteins in subfertility of polycystic ovarian syndrome.

Obesity and hyperandrogenemia are known to have adverse effects on both developing follicle and endometrium receptivity in polycystic ovarian syndrome (PCOS). Insulin resistance also contributes to this dilemma as a cause or a consequence and leads to worsening of the clinical picture. The difficulty in obtaining pregnancy despite the presence of a large number of oocyte has concentrated our attention on oocyte quality and development. However, the occurence of subfertility has also caused us to investigate the presence of different etiologic agents in non-obese PCOS women with normal androgen and insulin levels. In this context peptides have become the most accused and investigated molecules in cases of impaired fertility due to PCOS. Most of the studies investigating the relationship between PCOS and peptide did not support each other. The difficulties in measuring peptide levels as well as the individual variations in peptide synthesis and release are possible causes of this incongruity. For all these reasons, the incorporation of studies investigating the relationship between PCOS, peptide and subfertility in an article has become critical to pioneering future work. Understanding the association between peptides and subfertility will help us to understand the effects of peptides on failed fertility in PCOS. Moreover, updating our knowledge about peptides may allow us designing new drugs to to treat subfertility in PCOS. This review provides a general summary of the mechanisms of action of neuroendocrine peptides in regulating reproductive events. Since it is not usual to discuss all peptides in this context, only the effects of key central and peripheral peptides on fertility in PCOS have been extensively addressed.