Abstract
Accessory organs of immature, non-rutting adult and castrated male ground squirrels (Citellus tridecemlineatus) have been shown to respond greatly to injections of male hormone prepared from bull testes and human male urine. 1 Synthetic androsterone,‡ reported to stimulate male accessories in castrated birds and mammals, 2 - 6 was administered to annual-breeding male ground squirrels in order to determine its effects on accessory reproductive organs during the season when testis hormone is released in minimal quantities, if at all, by gonads in normal males of this species.
The low state of reproductive organs in 25 normal males was evaluated by the following methods without the actual removal of tissues, in order to evade possible compensatory hypertrophy: (1) inspection of scrotal skin for pigmentation, (2) manual palpation of bulbar gland, (3) examination of epididymis and ductus deferens at exploratory laparotomy, and (4) measurement of the testis through a peritoneal incision. Testis size, as an index of the hormonal condition of accessories, owes its reliability to the fact that the writer has considered gross and histological data (concerning testis and 6 accessory reproductive organs) for more than 250 normal males of this species killed at various stages of the sexual cycle since 1931.
Sixteen of these 25 animals were treated with androsterone, (dissolved in olive oil) while 9 were sacrificed as operated uninjected controls. Thirteen immature and 3 adult males were given from 0.5 mg. to 1.5 mg. of androsterone daily for periods ranging from 20 to 31 days, and were autopsied one day after the last injection. Sacrifice of experimental and control animals occurred during the interval from August 18th to November 6th; 84 other normal males killed between these dates since 1931 served as additional controls.
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