Regulated anion secretion in cultured epithelia from Sertoli cells of immature rats

Abstract

Cultured epithelia of Sertoli cells from prepubertal rats were grown on Matrigel‐coated millipore filters for short‐circuit current (Isc) measurements. Under basal conditions, these epithelia exhibited a ‘zero’ transepithelial potential difference, a ‘zero’ short‐circuit current and a transepithelial resistance of 60 Ω cm2. Forskolin (100 μm) and 8‐(4‐chlorophenylthio)‐cAMP (cpt‐cAMP) (100 μm) added to the apical side stimulated the Isc (forskolin, peak ΔIsc= 1.32 ± 0.16 μA cm−1; cpt‐cAMP, peak ΔIsc= 0.88 ± 0.16 μA cm−2). ATP (100 μm) added apically elicited a Isc response (peak ΔIsc= 6.45 ± 0.28 μA cm−2) which was similar in magnitude to that of 1 μm thapsigargin (peak ΔIsc= 6.09 ± 0.44 μA cm−2). The potency of the responses to other nucleotides: UTP ≥ ATP > ADP >> AMP = adenosine indicates the involvement of a mixture of P2Y receptors. Removal of extracellular Cl− and HCO3− reduced the Isc response to ATP by 70 % and 40 %, respectively. Removal of K+ had no effect, whereas removal of Na+ attenuated the Isc response. The response to ATP was insensitive to agents known to block anion secretion (except apical diphenylamine‐2‐carboxylate (DPC) and DIDS). The resistance to perturbation by pharmacological agents may be a unique property of the seminiferous epithelium. Whole‐cell current recordings in cultured rat Sertoli cells demonstrated a DIDS‐sensitive outwardly rectifying Cl− conductance with activating and inactivating characteristics at depolarizing and hyperpolarizing voltages, respectively. The stimulation of electrogenic ion transport by ATP may be part of a complex mechanism regulating fluid secretion by the testis. Cultured Sertoli cell epithelia are shown to provide a useful model to investigate transepithelial transport in the seminiferous epithelium.

Adenosine Triphosphate Induces Ca2+ Signal in Epithelial Cells of the Mouse Caput Epididymis Through Activation of P2X and P2Y Purinergic Receptors1

“…Recently, it has been shown that the purine nucleotide-activated P2Y receptors can cooperate with ␣ 2 -adrenoceptors to mobilize intracellular free calcium [18]. Furthermore, ATP has been shown to regulate anion transport in rat Sertoli cells [35]. Because extracellular ATP has multiple effects on cells by activating several receptor signaling pathways, the action of ATP released from cells is strictly regulated by several ecto-ATPases, which reduce the levels of extracellular ATP [21].…”

Ectonucleotidase activities in Sertoli cells from immature rats

“…Several reports have demonstrated the presence of adenosine receptors in Sertoli cells (10,11) and their modulation by adenosine and different adenosine analogues (4,8,9). The purinoreceptor subtype P 2Y2 is present in these cells (5) and its modulation by ATP has been well demonstrated (5)(6)(7). In Sertoli cells, extracellular ATP and adenosine can modulate the hormonal response to FSH, decreasing cAMP levels (4,5,(8)(9)(10), and can regulate anionic (6) and transferrin secretion (7) and the intracellular levels of Ca 2+ by inositol phospholipid turnover (5).…”

“…Previous studies have demonstrated that adenosine nucleotides can modulate Sertoli cell responses through the purinoreceptors present on these cells (4)(5)(6)(7)(8)(9)(10).…”

Estrogenic regulation of bicarbonate transporters from SLC4 family in rat Sertoli cells

“…After a steadystate period of at least 10 min, DIDS (0.5 mM), an inhibitor of HCO 3 -membrane transporters, was added or not to the basal side of the preparation. After 10 min, ATP (2 mM) was added to the apical side of the preparation and the short-circuit current (I sc ) was followed for up to 2 h, as described [21]. I sc was plotted as the average (±SEM) of the fractional values calculated by dividing each value by the initial I sc value Table 1 Genes, oligonucleotide sequence, and respective conditions for PCR amplification of anion exchanger 2 (AE2), Na ?…”