Pineal function in long term blinded male and female golden hamsters

Removal of the eyes from either adult male or female golden hamsters causes the reproductive organs to involute within 9 weeks. The testes and accessory sex organs (seminal vesicles and coagulating glands) of eyeless hamsters are reduced to one-sixth and one-seventh their normal size, respectively. The histologic structure of these organs also indicates marked hypofunction and decrease gonadotropin production or release. Although the ovaries of blinded females do not decrease in size they exhibit a diminution in follicular development and an increase in the amount of interstitial tissue. The uteri of the same animals are about one-fourth the size of those in control hamsters. Atrophy of the reproductive organs in eyeless hamsters of both sexes is a consequence of an activated pineal gland since if removal of the eyes is accompanied by removal of the pineal gland the gonads remain grossly and microscopically normal. If hamsters are maintained for 27 weeks after blinding, the gonads regenerate to an adult condition even though the pineal gland is intact. Thereafter, the gonads remain similar to those of untreated controls or blinded pinealectomized hamsters.