Rucker Cleveland

Cyclic histological variations in the anterior hypophysis of the dog

Introduction. The pioneer work of SM~T~ and E~GLE (33) and of ZONDEK and ASCHHEnV~ (42) has demonstrated that the anterior lobe of the hypophysis is a stimulator of ovarian activity. Furthermore, it has been shown, by means of certain experimental procedures, discussed below, that it is possible either to increase or decrease the capacity of the anterior lobe to stimulate the ovary. The work of ENGLE (8) and of EvAz~s and SIMPSON (10) has demonstrated that castration increases the capacity of the anterior lobe of the rat to bring about enlargement of the ovaries of immature mice. In this laboratory we have found that the anterior hypophyses of female rats, castrated for 60 days, have ten times as great a capacity to induce ovulation in the rabbit as tha t of normal female rats (38). EvANs and SI~iPsoN (11) have reported tha t admini. stration of fresh thyroid to donor rats increases the capacity of the anterior lobe to stimulate the ovary, a finding which has been confirmed by VAN HORN (35). LEONARD, MEYE~ and HIsAw (19) have found that injection of oestrin for a prolonged period decreases the capacity of the anterior lobe to stimulate the ovary. BACON (2) and PHILIPP (25), using anterior lobe material from pregnant cows and pregnant women, respectively, found that such tissue exhibits a marked decrease in capacity to stimulate the ovaries of immature rats and mice. Recently in this laboratory, KT.INGLER, BU~tC~ and CVNNZ~OHA~ (16) have demonstrated that subcutaneous injection of an alcoholic extract of human placenta increases theovarian stimulating capacity of the anterior lobes of eastrateded female rats. MASON and WOLFE (23 and 24) have demonstrated

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.