Patency of the follicular epithelium in Rhodnius prolixus: a re-examination of the hormone response and technique refinement

Abstract

The size of the extracellular spaces revealed by Evans' blue penetration into the follicular epithelium of Rhodnius prolixus increases with the stage of vitellogenesis. This was found to be true of follicles incubated in control media, as well as those whose spaces had been stimulated to expand by incubation in juvenile hormone (JH) or the analogue ZR515. An improved method of estimating hormonal effects in vitro utilizes a regression analysis of patency index relative to follicle length; with control follicles the slope was 0.44, whereas hormone- and analogue-treated follicles yielded slopes of 0.86 and 1.09, respectively. Some pitfalls of the dye penetration test are outlined.