Philip E. Smith

Hastening Development of Female Genital System by Daily Homoplastic Pituitary Transplants.

The success of the writer 1 , 2 in restoring the atrophied sex apparatus of the hypophysectomized rat by daily homoplastic pituitary transplants, made it seem not unlikely that the transplants might hasten the development of the sex apparatus of the immature unoperated animal. A series of experiments was therefore undertaken in which homoplastic pituitary transplants, taken from full-grown rats of both sexes, were made daily in females which would not normally mature for some time. It was found that this treatment rapidly induced the changes characteristic of sexual maturity, (opening of the vagina, uterine hyperemia and distension, follicle and corpora formation). These changes were secured as early as the weaning date (22nd day of life), the animals weighing approximately 40 grams. The vaginal smear was oestral in type. Structurally the changes indicative of sexual maturity were present in all parts of the genital system. When the transplants were commenced at about the weaning date, sexual maturity was induced in 5 or 6 days. If the transplants were begun in animals considerably younger, a longer treatment was required. This was shown by one series (3 treated and 3 controls), in which treatment was instituted on the 14th day of life. One of the treted animals matured sexually in 8 days, two in 10 days. In no case have these transplants failed to bring about sexual maturity at a considerably earlier period than it would normally have occurred. The results obtained transcend all normal variability. Experiments show that the anterior pituitary component of the transplant is responsible for the induction of the premature sexual maturity. Kymographic records of the spontaneous contractions of the isolated uterus in Ringers solution show that the amplitude of these uterine contractions in the treated animals greatly exceeds those of the controls; they, in fact, are equal or nearly equal to those of an animal which matures at the usual age.

Increased Skeletal Effects in A. P. Growth-Hormone Injections by Administration of Thyroid in Hypophysectomized, Thyro-Parathyroidectomized Rats

It has been shown (Smith 1 ) and confirmed by a number of investigators that the injection of beef A.P. growth preparations, or the daily implantation of rat pituitaries caused a resumption of growth in rats dwarfed by hypophysectomy. Thyroid administration does not cause growth in the absence of the A.P. (Smith, Greenwood, and Foster 2 ). It has been further shown (Flower and Evans 3 ) that the A.P. growth hormone induces growth in rats dwarfed by thyroidectomy, a finding in harmony with the fact that A. P. extracts cause growth in hypophysectomized rats even though they may not repair the atrophied thyroids. It thus seems clear that of these 2 glands the A.P. only is essential for growth. These findings, however, do not demonstrate that the thyroid may not normally aid the growth action of the pituitary or may not increase the effectiveness of preparations made from it. I have attempted to secure evidence upon this by giving growth hormone∗ with and without concurrent thyroid feeding in a series of rats in which both the hypophysis and thyroid (as well as the parathyroids) had been removed during the active growing period. All members of each series received the same dosage of growth hormone, one member receiving, in addition, thyroid. A dosage of thyroid was administered which did not prevent an increase in weight (100 mg. powder 2-3. times per week). Four series of animals have been treated over a period of several weeks. In each case the skeletal growth of the rats receiving thyroid in addition to the A.P. extract was distinctly above that of the rats receiving the extract only. In 3, the weight increases were greater also.

Induction of Precocious Sexual Maturity in the Mouse by Daily Pituitary Homeo and Heterotransplants.

Homeotransplants. Sexual maturity is induced in the female mouse by daily pituitary homeotransplants even more rapidly than in the rat. In the rat 8 to 10 daily transplantations are required to bring about sexual maturity at the weaning date (22nd day of life); if the transplants are commenced at about the weaning date, 4 to 6 transplantations only are necessary. 1 In the mouse 3 transplantations made on successive days induced sexual maturity whether begun at the weaning date (20th day of life) or 3 days previously. The structural and physiological changes resulting from this treatment are those characteristic of normal sexual maturity. The vaginal canal is established and contains the cells typical of oestrus, the uterus is engorged, and many large follicles and corpora are present. In the immature male mouse, as with the male rat, the response of the genital system to the pituitary transplants is much slower than with the female. Four daily transplantations into males varying from 18 to 22 days of age give no, or only a slight increase in size of the testes, and but a small increase (about 25 per cent) in the remainder of the genital system. When the transplants are given even for 17 successive days the testes do not show the marked weight increase over the untreated control that is shown by the remainder of the genital tract, the latter being some 10 times heavier than that of the controls. Even though the testes show, as compared with the rest of the genital system, only a relatively small increase in weight from the transplantations, nevertheless it appears that the implanted pituitary affects the genital tract through the intermediary of the testes, for in their absence no growth response results in the remainder (7% the genital system.

Genital System Responses to Daily, Pituitary Transplants.

The daily transplantation of pituitary tissue from full-grown rats into immature female rats hastens development. 1 Daily, pituitary homeotransplants, the donors being adults, likewise hastens the growth of the genital system in the immature male rat. Nine animals from 4 litters have been treated, each having 1 or more littermate control. Results gained from 1 of these litters illustrate the typical response to the transplants. Protocol. Of a litter of 4 males daily pituitary homeotransplants were begun in 2 on the 14th day of life, 2 serving as controls. The animals were nearly identical in weight. One treated and 1 control were autopsied 10 days later (age 24 days). Treated animals: Weight, 44 gm.; weight of both testes, 0.254 gm.; of genital system exclusive of testes, 0.480 gm. Control: Weight, 43 gm.; weight of testes, 0.240 gm.; of genital system exclusive of testes, 0.249 gm. The remaining 2 animals were autopsied at the age of 31 days, the treated animals thus having received 17 transplants. Treated animal: Weight, 74 gm.; weight of both testes, 0.603 gm.; of genital system exclusive of testes, 0.916 gm. Control: Weight, 69 gm.; weight of both testes, 0.339 gm.; of genital system exclusive of testes, 0.409 gm. (Weight of the genital system include the empty urinary bladder.) It is seen that there is no marked effect upon the size of the testes in the younger animal from these transplants. The genital system, exclusive of the testes, however, shows a marked increase in weight, transcending all normal variability. It is nearly double normal weight. The other (older) animal shows that with a more prolonged treatment, and possibly also due to an increase in age, the testicular response also becomes marked.

Ovarian Response of Hypophysectomized Rats to Urinary Follicle-Stimulating Principle.

Zondek 1 and Kurzrok, 2 by injections in normal immature female rodents, have demonstrated that certain urines (after ovariectomy and the menopause) may induce predominantly a follicular growth. Leonard 3 has shown that the principle in this urine can be differentiated from that in P.U. by the rabbit ovulation test.

Retardation of metamorphosis in the Colorado axolotl by the intraperitoneal injection of fresh bovine hypophyseal anterior lobe substance1

As is well known, the axolotl in its native habitat may retain its larval condition for long periods, even becoming sexually mature (neotonous). When treated with thyroid, when placed in unfavorable conditions or when transported to a lower and warmer region it rather promptly metamorphoses. This delicate-balance obtaining in the internal secretory glands (the thyroid and hypophysis here being of especial interest) of this form would appear to make it especially useful in the experimental modification of the activities of these glands. Since the experimental transplantation of the anuran anterior hypophysis into the hypophysectomized tadpole (Allen) and into the normal tadpole (Swingle) and the intraperitoneal injection of bovine anterior hypophyseal substance into the pituitaryless tadpole (Smith) appear to stimulate the thyroid, thus hastening or inducing metamorphosis, it would seem that the injection of this substance might be expected to accelerate metamorphosis in the axolotl. The opposite reaction, however, is evoked, the larval condition being decisively prolonged. The experimental injection of fresh bovine anterior lobe hypophyseal substance, intraperitoneally, into the Colorado axolotl during the months of May to September of the present year has resulted in a definite retardation in the metamorphosis of this form. Anterior lobe substance appears here to have given a “paradoxica:” reaction and the usual effect of thyroid activity (which most investigatorshold as immediately responsible for metamorphosis) has been greatly postponed. Pronounced darkening of the axolotl resulted from these injections of anterior lobe sulbstance, the specimen becoming after repeated injections a jet black

Mating Reaction of Hypophysectomized Male Rats Treated with Pregnancy Urine Extracts

Adult male rats are known to lose all libido immediately after hypophysectomy (Smith 1 ), though matings for some time after castration have been reported. Also motile sperm have been demonstrated in the epididymis of hypophysectomized male rats no longer than 21 days after the operation (White 2 ). Complete fertility is restored to hypophysectomized males by giving rat pituitary implants (Smith 1 ). Since it was observed that pregnancy urine extract (P.U.) slowed the degenerative changes in the testes of hypophysectomized rats (see previous article), matings were attempted at various times with oestrus females where treatment was begun immediately fob lowing the operation. Of 7 hypophysectomized males, 6 mated one or more times. In a total of 25 attempts at mating, 13 were positive and, furthermore, 11 of these were fertile, producing normal litters. It was most interesting that of these fertile matings some took place 18, 20, 32, 34, and 47 days following hypophysectomy. It was not surprising because of the enlargement of the accessories that matings occurred, but the extended period of fertility was unexpected. P.U. treatment restored the atrophied genital tract of hypophysectomized males to a degree when treatment was postponed following the operation. That some hypophyseal factor is necessary and facilitates the restoring of the atrophied germinal epithelium is quite evident from our work, for the restoration secured by the injection of P.U. is not as complete as is the case with implants. The relationship of P.U. to hypophyseal gonad stimulatory substances becomes even more obscure in the light of the findings reported in this series of papers.

The production of the adiposogenital syndrome in the rat, with preliminary notes upon the effects of a replacement therapy.

The answer to the question whether the genital atrophy, skeletal undergrowth, and excessive adiposity of the adiposogenital syndrome are due to a pituitary deficiency or to an injury of the hypothalamus without pituitary involvement has rested heretofore upon observation made in two closely allied ways, (1) the extent of the injury inflicted as determined at the time of operation, (2) the extent of the injury as determined by autopsy and a study of sections. Both of these methods are open to the objection that the most careful study may fail to reveal the extent of damage done. Another method is available for determining the significance of the pituitary and brain injury in the genesis of this syndrome, namely, that of a replacement therapy. If we have any confidence in the functional specificity of the endocrine glands, it follows that we must admit the significance of a pituitary impairment as the causative factor if the adiposogenital syndrome or any of its components can be corrected by pituitary administration. This point has been previously discussed (Smith and Smith) in connection with reports upon a replacement therapy in the hypophysectomized tadpole, in which it was shown that the enlargement of the fat organ, and the pigmentary, growth, and endocrine disturbances which invariably follow hypophysectomy in the tadpole, can be corrected by pituitary administration. It is our intention to use this method to make an analysis of the part played by the pituitary in the adiposogenital syndrome of the mammal.