Doris Phelps

Reaction of Anterior Hypophysis of Immature Rat to Placental Hormones.

Lehmann 1 has reported that injection of placental extracts brings about pregnancy changes in the anterior hypophysis of the female rat. Collip and his associates 2 have recently reported that long term injection of the anterior-pituitary-like hormone of the placenta brings about an enlargement of the anterior hypophysis, which is later followed by a decrease. We have carried out a series of experiments in which we have studied the histological changes in the anterior pituitaries of immature rats which had received injections of a relatively crude oestrin-free extract of placenta. The method of preparation of this extract has been described. 3 We have used litters of immature female rats, 25 to 35 days old. Half of the animals in each litter received 2 subcutaneous injections daily for 6 to 8 days. The remaining animals in the litter served as controls. The results of the injections were constant and definite. Table I illustrates some of our findings and shows that the ovaries of the injected animals were markedly increased in size.† The swollen and hyperemic pituitaries of the injected animals exhibited a moderate but invariable weight increase when compared with those of the controls. The ovaries and pituitaries of all animals were weighed on a torsion balance accurate to 0.5 mg. (Hartmann and Braun). Analysis of Table I reveals that the increase in the size of the hypophysis was as a rule greatest in the animals in which the ovarian reaction was greatest, a fact already noted by Collip and associates. Complete serial sections of the hypophyses of both the control and experimental animals were cut. One section from each ribbon of 25 was mounted, giving a complete set of sections. Every fifth or sixth slide of each set of sections was studied.

Reactions of Ant. Pituitaries of Male Rats to Administration of Ant. Pituitary-Like Substance and to Oestrin.∗

Recent studies 1 indicated that injections of massive amounts of oestrin into normal female rats induced weight and morphologic reactions in the anterior pituitary similar to those obtained by the injection of the anterior pituitary-like substance of pregnancy urine. Both of these substances induced a marked weight increase in the gland, a marked loss of granules from the basophiles and a less evident loss of granules from the eosinophiles (in A.P.L. rats whose ovaries contained active corpora lutea). Furthermore, it has been found that administration of the A. P. L. factor has no action on the anterior hypophysis of the castrated rat 2 , 3 but that oestrin is capable of direct action on the anterior lobe of the castrated rat. 4 The experiments described below were carried out in order to compare the reaction of normal male rat pituitaries to administration of these 2 factors. Fourteen adult male rats received daily injections of 25 rat units of an extract of pregnancy urine† for 10 days. Another group of 10 rats received daily injections of 200 rat units of oestrin† for 10 days. A third group of 30 normal mature male rats served as controls. At autopsy, body, pituitary, testes and prostate and seminal vesicle weights were secured. Serial sections of all glands were cut. 5 representative sections from each series were studied and cell counts made. Quantitative results are presented in Table I. Administration of the A. P. L. substance to male rats did not increase the weight of the pituitary gland over that found in the controls (Table I). This was in contrast to previous findings in female rats. Confirming the findings of Severinghaus 2 the anterior pituitaries of the injected male rats exhibited a marked loss of granules from practically all the basophiles although a few granular basophiles were present (Table I).

Effect of Feeding Thyroid on Anterior Hypophysis of the Female Albino Rat.

Summary Twenty-eight female rats were fed amounts of desiccated thyroid ranging from 250 to 1,000 mg. daily. The oestral cycle was suppressed to varying degrees, dependent on the dosage of thyroid. The pituitaries were subnormal in weight. Histologically the anterior lobes exhibited certain changes : most notable was a slight increase in the percentage of the basophiles and a definite increase in the size and granular content of these cells. The granules stained a purple-red which varied to a dull brick-red; in normal female rats (virgin and killed during the normal oestral cycle) the basophiles take a deep blue stain. The changes in the basophiles were most marked in those animals in which the suppression of the oestral cycle n-as most evident.