Effects of Acute and Chronic Treatments with Atrial Natriuretic Factor (ANF) on the Leydig Cells of the Rat Testis

Abstract

Acute ANF bolus administration (40 μg.kg⁻¹) did not affect sec retory activity and morphology of rat Leydig cells. Prolonged (7-day) ANF infusion (20 μg.kg⁻¹.h⁻¹), on the contrary, elevated both basal and hCG-stimulated testosterone blood concentration, and caused a notable hypertrophy of rat Leydig cells. Leydig-cell hyper trophy was due to increases in the volume of all the organelles involved in cholesterol and testosterone synthesis (i.e. mitochon dria, smooth endoplasmic reticulum and peroxisomes). These findings suggest that ANF, when chronically administered, is able to stimu late the growth and steroidogenic capacity of rat Leydig cells.