Duration of Estrus in Ovariectomized and Adrenal-Ovariectomized Rats Before and After Theelin

Abstract

Within the last few years numerous papers have appeared on several phases of the adrenal problem without adding, as Rogoff has recently discussed, any very definite contribution. The literature on the sex-relationship has been especially confusing; and the many references cited by Kroc and Martin indicate that total adrenalectomy may cause no change, a slight modification or complete inhibition of the estrus cycles. These authors made a point of the fact that the weight-loss of adrenalectomized rats must be restored before normal estrus is again established following injections of the cortical hormone. Yet this same result, as to normal estrus in adrenalectomized rats, may be obtained by allowing the animals to drink salt solutions (Kutz, et al.). This led us to study, by a different procedure, the theelin-inhibition problem previously reported. The present approach has been first, to compare ovariectomized and adrenal-ovariectomized rats as to the estrus occurring on successive days following the operation; and second, the duration and reoccurrence of estrus that followed various doses of theelin. The estrus cycles were taken daily, by the pipette method, for 2 weeks or longer preceding and following the operation. Six to 10 days following the operation, all rats were placed on Ringer's solution as their only source of drinking water. A few animals died before the sixth day; but these are not considered in the data. All animals were autopsied. In 4 of the 60 rats composing the adrenal-ovariectomized group, adrenal fragments were found. Ovarian fragments were not seen in either group. The per cent of rats in estrus each day for 10 days before and 12 days after ovariectomy (group O) is shown in Fig. 1; and similar results for adrenal-ovariectomized rats (group A-O) are found in Fig. 2. The 2 figures are almost identical in every way.