Transferrin Secretion in Response to Different Modes of FSH Stimulation and Cycloheximide in Superfused Sertoli Cell Cultures

Abstract

The influence of different modes of FSH stimulation and cycloheximide on transferrin secretion by rat Sertoli cells was investigated using a superfusion culture system. Sertoli cells from 18-day-old rats were cultured in serum-free medium on Matrigel-covered slides first in static conditions for 19 hours, and then superfused at a flow rate of 2.5 ml/hour. After an equilibration period of 48 hours to establish the basal rate of transferrin secretion, the cultures were exposed to various modes of FSH stimulation. Sertoli cells stimulated intermittently (20 min/2 hours) up to 22 hours responded to each consecutive FSH pulse with a rapid increase of transferrin secretion followed by a decline toward basal values. Continuous 22-hour exposure to FSH elicited an immediate increase followed by irregular fluctuations and a transient decline towards the baseline. With either mode of FSH stimulation, there was a secondary prolonged increase in transferrin secretion. Although cultures stimulated intermittently or continuously during the entire experimental period (22 hours) secreted similar cumulative amounts of transferrin (10.8 +/- 0.5 micrograms and 11.1 +/- 0.8 micrograms, respectively), there was a direct correlation between the secreted amount of transferrin and the duration of FSH exposure up to 8 hours. Addition of cycloheximide decreased both basal and FSH-stimulated transferrin secretion. However, even when cycloheximide was added 1 hour before FSH, an early secretory peak in response to FSH was still observed.(ABSTRACT TRUNCATED AT 250 WORDS)