Reduction of Serum LH and Testosterone in Male Rats by a Partially Purified Bovine Pineal Extract

Abstract

Defatted bovine pineal glands were extracted with acetic acid and further purified on Sephadex G-25 to yield 3 antigonadotropic fractions designated as F3, F4 and F5. Each of the fractions was administered separately at either 5 or 10 g eq (equivalent to starting wet weight of tissue) dose levels daily for 5 consecutive days to young mature male rats. Animals were necropsied 24 h after the last injection. None of the fractions had an effect on accessory gland weight, although the fraction F4 significantly reduced testicular and anterior pituitary weights, while the higher dose of the F5 fraction significantly reduced the anterior pituitary weight. Each fraction significantly reduced the concentration of serum LH [luteinizing hormone] when administered at the higher dose level. Animals receiving either dose of the F4 fraction displayed significantly reduced concentrations of serum testosterone, while those animals receiving either of the other 2 fractions did not. Further evidence was provided that some substances other than melatonin in the bovine pineal are antigonadotropic.