Islet cell population changes induced by short term ovariectomy.

Changes induced in the endocrine pancreas were studied in rats 14 days after ovariectomy. The study was performed in age matched control (C) and ovariectomized (O) rats. The pancreases were stained using the p-aldehyde-fuchsin and the peroxidase (using antiinsulin serum) methods. Morphometric analysis was done using the Weibel technique. The results obtained show a diminution in the total volume of the endocrine pancreas accompanied by an increment in the individual islet volume following the ovariectomy. The last change would be the consequence of an increment in the number of islet cells (mainly the B cell population), without change in cellular volume, i.e., hyperplasia without hypertrophy. These changes might explain the apparent discrepancy regarding the effect of ovariectomy upon insulin secretion when this process is studied using either the total pancreas preparation or the isolated islet model.