Carbamates are widely used and known around the world as pesticides in spite of also having medical applications. This class of chemicals is classified as acetylcholinesterase inhibitors, blocking acetylcholine hydrolyzation in a reversible manner. Their lack of species selectivity and their reported high toxicity can induce, upon exposure, adverse outcomes in male fertility that may lead to infertility. In addition, they are also considered endocrine-disrupting chemicals and can interfere with the hypothalamic–pituitary–testicular axis, essential for the normal function of the male reproductive system, thus being able to provoke male reproductive dysfunctions. Although the molecular mechanisms are not fully understood, various signaling pathways, such as those mediated by acetylcholine or kisspeptin, are affected by exposure to carbamates, thus compromising steroidogenesis and spermatogenesis. Over the last decades, several studies, both in vitro and in vivo, have reported a myriad of negative effects of carbamates on the male reproductive system. In this review, an up-to-date overview of the impact of carbamates on the male reproductive system is discussed, with an emphasis on the role of these compounds on acetylcholine regulation and the male endocrine system.

The incidence of male infertility has been increasing over the years and is now becoming a serious health problem. This trend has been followed by an increase in metabolic diseases, which are known to induce clear alterations in testicular metabolism, although the underlying mechanismremain unclear. Testicular metabolism displays several unique features, with testicular somatic cells being central in providing the conditions needed for spermatogenesis, including its nutritional and hormonal support. In addition to glucose and lactate, the two main energy sources used by the testis, glycogen is also present in testicular cells. Glycogen metabolism is a potential source of glucose to both testicular somatic (namely Sertoli and Leydig cells) and germ cells. Many of the enzymes involved in the pathways of the synthesis and degradation of glycogen were identified in these cells, emphasising the relevance of this complex carbohydrate. Glycogen, however, has other non-canonical functions in testicular cells; besides its role as a source of energy, it is also associated with events such as cellular differentiation and apoptosis. In this review, we address the relevance of testicular glycogen metabolism, focusing on its role in Sertoli and Leydig cells and spermatogenesis. In addition, all the available information on the role of glycogen and related pathways in male infertility cases is discussed. Our discussion highlights that glycogen metabolism has been somewhat overlooked in testis and its contribution to spermatogenesis may be underestimated.