1α,25-(OH) vitamin D prevents insulin resistance and regulates coordinated exocytosis and insulin secretion.

Vitamin D is associated with improvements in insulin resistance and glycemia. In this study, we investigated the short-term effect of 1α,25(OH) Vitamin D (1,25-D) and cholecalciferol (vitamin D) on the glycemia and insulin sensitivity of control and dexamethasone-induced insulin-resistance rats. Ca influx responses to 1,25-D and its role in insulin secretion were investigated in isolated pancreatic islets from control rats.

Crosstalk in the non-classical signal transduction of testosterone and retinol in immature rat testes.

This study aimed to investigate the effects of the interaction between testosterone and retinol on the rapid responses of cultured Sertoli cells obtained from 10-day-old immature rat testes. Non-classical actions of testosterone and retinol were investigated, and the activities of L-type voltage-dependent calcium channels (L-VDCC) and voltage-dependent potassium channels (Kv) were determined by measuring Ca influx in whole testis. Additionally, the effects of testosterone and retinol on these channels were studied in primary culture of Sertoli cells using the patch-clamp technique.

Acute effect of bisphenol A: Signaling pathways on calcium influx in immature rat testes.

We investigated the acute effect of low concentrations of BPA on calcium influx and the mechanism of action of BPA in this rapid response in the rat testis. BPA increased calcium influx at 1 pM and 1 nM at 300 s of incubation, in a similar manner to that of estradiol. At 1 pM, BPA stimulated calcium influx independently of classical estrogen receptors, consistent with a G-protein coupled receptor.

Epitestosterone- and testosterone-replacement in immature castrated rats changes main testicular developmental characteristics.

Epitestosterone is the 17α-epimer of testosterone and has been described as an anti-androgen, since it inhibits the effects produced by testosterone and dihydrotestosterone via the nuclear androgen receptor (nAR). However, epitestosterone also displays an effect which is similar to the non-classical effect of testosterone, depolarizing the membrane potential of Sertoli cells and inducing a rapid Ca uptake. This study aimed to investigate the effects of a treatment with epitestosterone on developmental parameters of immature rats.

Non-classical effects of androgens on testes from neonatal rats.

The intratesticular testosterone concentration is high during the early postnatal period although the intracellular androgen receptor expression (iAR) is still absent in Sertoli cells (SCs). This study aimed to evaluate the non-classical effects of testosterone and epitestosterone on calcium uptake and the electrophysiological effects of testosterone (1μM) on SCs from rats on postnatal day (pnd) 3 and 4 with lack of expression of the iAR. In addition, crosstalk on the electrophysiological effects of testosterone and epitestosterone with follicle stimulating hormone (FSH) in SCs from 15-day-old rats was evaluated.

Non-classic androgen actions in Sertoli cell membrane in whole seminiferous tubules: effects of nandrolone decanoate and catechin.

Studies show a mechanism of action of testosterone, nandrolone and catechin as agonists of the membrane androgen receptor. The aim of this work is to investigate the non-classical effect of androgens and catechin in Sertoli cells from immature rats. The membrane potential of Sertoli cells in whole seminiferous tubules was recorded using a standard single microelectrode technique.