Electrophysiological Changes of Sertoli Cells Produced by the Acute Administration of Amino Acid and FSH

Abstract

Electrophysiological studies were carried out using seminiferous tubules of "Sertoli cell enriched testes" of rats irradiated in utero. Sertoli cells were inserted with glass microelectrodes in a superfusion chamber continuously perfused with KRb buffer. The topical application of FSH (4.0 mU/ml) produced a biphasic effect characterized by a rapid hyperpolarization (less than 3 s) followed by depolarization. The depolarizing effect of FSH was prolonged and potentiated in the presence of 5 mmol/l alpha-methylamino-isobutyric acid in the bath medium of the superfusion chamber. Verapamil, at a dose (250 mumol/l) that nullified the stimulatory action of FSH in the amino acid transport, suppressed the depolarizing effect of FSH. It was concluded that in immature rat testes FSH produces electrophysiological changes that mediate the stimulatory action of the amino acid transport.

Rapid signaling responses in Sertoli cell membranes induced by follicle stimulating hormone and testosterone: Calcium inflow and electrophysiological changes

“…Some of these effects occur very rapidly, within seconds to a few minutes, and they are well-illustrated by the action of FSH on membrane potential (MP) changes and Ca 2+ uptake through L-type VDCCs in the Sertoli cells of immature rat testes (Wassermann et al, 1992b). In immature Wistar rats, the pleiotropic response induced by FSH includes biphasic Sertoli cell MP changes that are specific to the rapid effects of FSH.…”

“…In immature Wistar rats, the pleiotropic response induced by FSH includes biphasic Sertoli cell MP changes that are specific to the rapid effects of FSH. For example, very short hyperpolarization (seconds) occurs, followed by a prolonged depolarization (more than 6 min) (Wassermann et al 1990(Wassermann et al , 1992a(Wassermann et al , 1992b. Hyperpolarization is blocked by tolbutamide (Jacobus et al, 2010), an inhibitor of ATP-sensitive K + channels (K + ATP ).…”

“…This dual signaling mechanism may explain the different electrophysiological effects of FSH on Sertoli cells during the proliferative phase: FSH action on Gs proteins will cause the hyperpolarization of the MP, most likely through the conversion of ATP to cAMP, which opens K + ATP channels (Nakashima and Vanhoutte, 1995); however, the depolarization phase associated with Ca 2+ entry (current) (Wassermann et al, 1992b) through the L-type VDCC and the consequent transport of MeAIB (Wassermann et al, 1992b) could be caused by Gi protein activation (Jacobus et al, 2010).…”

“…This phase is linked to the rapid entry of Ca 2+ (Wassermann et al, 1992b;Loss et al, 2007) and the Ca 2+ -dependent transport of neutral amino acids by the A system (Cruz Curte and Wassermann, 1985;Wassermann et al, 1992a). In these experiments, PTX, verapamil and wortmannin were used as pharmacological tools to analyze the signaling pathway of FSHinduced effects (Jacobus et al, 2010).…”

“…In a previous study by our group (Wassermann et al, 1992b), it was found that the average resting potential in Sertoli cells of enriched seminiferous tubules from 15-day-old rats was −44 mV± 0.5 (n= 48), ranging from −35 mV to −60 mV. To exclude possible error due to the heterogeneous population of seminiferous tubules, only cells with a resting potential more negative than −35 mV were included in the experiments.…”