Testosterone level is low in insulin-resistant type 2 diabetes. Whether this is due to negative effects of high level of insulin on the testes caused by insulin resistance has not been studied in detail. In this study, we found that insulin directly binds to insulin receptors in Leydig cell membranes and activates phospho-insulin receptor-β (phospho-IR-β), phospho-IRS1, and phospho-AKT, leading...

We investigated the cardiovascular responses to acute hypercapnia during the menstrual cycle. Eleven female subjects with regular menstrual cycles performed hypercapnic rebreathing tests during the follicular and luteal phases of their menstrual cycles. Ventilatory and cardiovascular variables were recorded breath by breath. Serum progesterone and estradiol were measured on each occasion. Serum...

Extracellular matrix regulates many cellular processes likely to be important for development and regression of corpora lutea. Therefore, we identified the types and components of the extracellular matrix of the human corpus luteum at different stages of the menstrual cycle. Two different types of extracellular matrix were identified by electron microscopy; subendothelial basal laminas and an i...

OBJECTIVE To evaluate the impact of two different luteal phase support protocols on gene expression of extracellular matrix (ECM) proteins and adhesion molecules in the human endometrium. DESIGN Eighty-four ECM protein and adhesion molecule genes were analyzed using array-based reverse-transcription polymerase chain reaction. SETTING Academic hospital. PATIENT(S) Nine oocyte donors. INT...

While the need for progesterone-based luteal phase support is well documented, the required treatment duration is not well established, and a practitioners' survey showed a wide range of empiric stopping points. It is suggested that an early stop can be based on assessing endogenous luteal activity on the day of pregnancy test. To examine this approach, data were retrospectively collected on 99...

Melatonin is a ubiquitous molecule and exhibits different effects in long-day and short-day breeding animals. Testosterone, the main resource of androgens in the testis, is produced by Leydig cells but regulated mainly by cytokine secreted by Sertoli cells. Melatonin acts as a local modulator of the endocrine activity in Leydig cells. In Sertoli cells, melatonin influences cellular proliferatio...

Progesterone supplementation is universally used and has been shown to be beneficial in supplementation of the luteal phase in IVF. There are multiple options and the most commonly used include intramuscular and vaginal progesterone. A progesterone vaginal ring is a novel system for luteal support with advantages of controlled release with less frequent dosing. This review examines options for ...

This study reports 21 IVF cases with excessive ovarian response, who received gonadotrophin-releasing hormone agonist (GnRHa) triggering for final oocyte maturation, followed by a human chorionic gonadotrophin (HCG)-based, progesterone-free, luteal support, individually timed ('luteal coasting') according to endogenous luteal progesterone concentrations. One patient developed a brief early-onse...

The objective of this study was to evaluate the influence of bull excretory products on the resumption of postpartum luteal function in primiparous, restricted-suckled cows. Hypotheses tested were that resumption of luteal function or proportions of cows that initiate luteal cycling did not differ among cows exposed to a bull (BE), exposed to excretory products of bulls (EPB), not exposed to a ...

The synthesis and secretion of progesterone in the corpus luteum are regulated by both endocrine and paracrine/ autocrine factors which affect the steroidogenic cells. Evidence suggests that these cells communicate via cell-cell junctional proteins, the connexins. Previously we have shown that connexin-43 is expressed in both human and baboon (Papio hamadryus anubis) corpora lutea, with differe...