Ethanol: A Gonadal Toxin in the Mature Rat of Both Sexes

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Abstract
A diet containing 5% ethanol, accounting for 36% of the total calories or a similar diet in which dextrimaltose was isocalorically substituted for ethanol, was fed to sexually mature adult male and female rats to determine whether alcohol feeding of such animals could produce gonadal failure as it does in weanling animals. After 4 mo of such feeding, alcohol‐fed animals of both sexes, when compared to isocalorically fed controls, demonstrated gonadal atrophy. Such atrophy was manifested by loss of ovarian (p < 0.05) and testicular (p < 0.01) mass, reduced sex steroid levels [progesterone in females and testosterone in males (both p < 0.05)], and atrophy of sex steroid responsive tissues. Such atrophy in the female rats studied was manifested by macroscopic and histologic evidence of loss of estrogen effect, while in the male only histologic evidence for loss of androgen stimulation could be demonstrated. In both male and female animals fed alcohol plasma luteinizing hormone (LH) levels were not increased as would be expected in the presence of such gonadal failure. In contrast, follicle‐stimulating hormone (FSH) levels were significantly increased (p < 0.01) in all alcohol‐fed animals when compared to isocalorically fed sex‐matched controls. These findings confirm and extend our prior studies that demonstrate that alcohol is a gonadal toxin. Moreover, they demonstrate that alcohol feeding to sexually mature animals is associated with a central hypothalamic‐pituitary defect in LH but not FSH secretion, as has been shown to exist previously in humans. Thus, alcohol is capable of producing gonadal injury in animals and presumably in man after, as well as before, puberty if ingested in sufficient quantities over a long enough interval.