REGRESSION OF ANTERIOR PITUITARY
REACTIONS II AND III IN THE MOUSE
OVARY
BY WALTER P. KENNEDY.
(From the Department of Physiology, Edinburgh University.)
(Received 4th December, 1933.)
A NUMBER of tests were carried out to find the duration of the changes induced in the mouse ovary by prolan, and whether they were completely evanescent or productive of more or less permanent alterations. The question is of some interest in view of Mandelstamm and Tschaikowsky's results (1931) in the production of temporary sterility in mice with prolan, and their experiment was repeated in a modified form with a few animals. Katzman has also reported that the B hormone from pregnancy urine produces profound ovarian luteinisation and complete inhibition of oestrus in rats, but that the impairment of the reproductive mechanism is not permanent.
METHODS.
microscopic examination of the ovaries was made. Seven more groups were given larger doses to discover if there was any difference in persistence.
In adult animals prolan also evoked ovulation, corpus luteum formation, luteinisation of unruptured follicles and haemorrhagic follicles. The effects were produced more irregularly than in the infantile animals in all cases, but five units produced after 100 hours evidence of ovarian disturbance. As a first trial, doses ranging from 5 to 15 units were given to a series of sixteen mice which had each borne a litter. Half were mated to males of proved fertility immediately all the injections were given. The remainder were mated 10-14 days later. Only three had litters; one of four 21 days after mating, and one of five 36 days after, both these having been mated just after the injection. The third, which had a litter of three after 125 days, was continually with a fertile male from the 14th day after treatment till it became pregnant. None of the remainder showed signs of pregnancy when they were killed at varying periods up to 174 days after mating, although they were left with the bucks during that time. As a control sixteen normal mice were mated at the same time and of these twelve became pregnant within 6 weeks, the remainder being sterile. These numbers are admittedly small, but the experiment was only designed as a preliminary one to obtain an idea of the range of effectiveness and variation. PROTOCOLS. Group 1 2 3 4 S 6 7 8 9 1 0 1 1 1 2 13 14 IS Dose in mouse units 2-S 2-5 5-o 8 0 2-S 5-O 2-S 2-S 5-0 2-S 2-5 5 0 5-o 2-S S-o I. , Days between treatment and killing 7 8 8 11 14 2 1 25 25 29 35 35 53 6 0 78
Infantile groups. Three mice in each.
Results
C.I. in all; B P. m i ; and luteirused G.F. in i. Regressing C.I. in I; B.P. in 2.
B.P. and ova in luteinised G.F. in 2; B.P. disappearing in 1. Many C.I. in 1; 2 died.
Infantile ovaries with shrunken C.I. in 2; several C.I. atretica in 1. B.P. beginning to be absorbed, many medium to large G.F.; C.I.
regressing and partly luteinised G.F.; infantile ovaries in 1. Much shrunken single C.I.; trace of luteinisation in 1 G.F.; 2
in-fantile ovaries. All infantile.
2 infantile; third with single B.P.; marked chromatolysis in mem-brana granulosa cells.
C.I. in beginning of atresia, B.P., uterus much enlarged and hyper-aemic; 2 other infantile ovaries.
Large G.F. showing chromatolysis of membrana granulosa in 2; 1 infantile.
Still B.P. and C.I. in 2; several C.I. in 1.
Large G.F. with chromatolysis; : infantile; 1 died
No C.I. or large G.F. in any, but ovaries about normal size. Medium G.F.; no C.I. or C. albicantia; 2 died.
Number of i 2 3 4 5 6 7 8 9 IO I I 1 2 13 H IS 16 Dose in mouse units 8 5 5 8 8 I I 1 2 1 2 IS 8 8 8 8 8 8 8 Days between treatment and killing — 28 35 38 — 38 38 38 49 81 83 84 89
I 2 S —
174
WALTER P. KENNEDY II. Adult mice.
Results
Litter of 4, 25 days after injection.
Many C.I , follicular cyst in one ovary, uterus pale. Several reddish C.I , uterus pink.
1 large C 1 only, considerable chromatohscs in G.F , uterus much enlarged.
Litter of 5, 35 days after injection.
C.I., retained ova in luteinised G F ; uterus enlarged h\peraemic. Ovaries very small, follicular cyst in one
Ovaries very small, but hyperaemic. Many corpora lutea; uterus much enlarged. No C 1.; ovary enlarged, uterus pale, animal very fat No C 1.; ovary and uterus both enlarged.
Many C.I. and C. albicantia; uterus thin, yellow. Large G.F., regressing C 1.
Many fresh C.I ; uterus enlarged, hyperaemic Litter of 3 after 125 days.
Red small ovaries, uterus infantile.
B.P. = blood points; C.I. = corpora lutea (or corpus luteum); G.F. = Graafian follicles.
DISCUSSION.
The effect of prolan injections on the ovaries of the infantile group were well marked, and showed a considerable degree of persistencet The primary changes were
the appearance of blood points or haemorrhagic follicles, precocious corpora lutea, and the luteinisation of follicles in which the ovum was still retained. No indication was obtained of the relation of these occurrences to each other, or to the dose administered. Just as in previous experiments (Kennedy) it was found that A.P.R. II is not always a precursor of A.P.R. I l l ; in some cases there was no sign of the former.
The standardisation of the preparation had been done in respect of the B com-ponent, but the A component was also abundantly present as was demonstrated by other experiments on rats. The mouse is much less sensitive to the A factor than is the rat, and none of the present series showed the A.P.R. I. Large Graafian follicles were found in some ovaries but in these cases the animals had passed the average age of puberty, and therefore this could not be ascribed to prolan. If the "A" hor-mone is indeed a separate entity its influence could not be shown apart from that of " B , " although it might well have co-operated with the latter.
was more difficult to assess because 21 days after treatment the mice had reached puberty, and the possibility of fresh corpora lutea had to be borne in mind. But after that date only five out of twenty-one surviving animals showed any corpora lutea and in two of these they were atretic.
In groups killed over 14 days after treatment approximately one-half of the total number had infantile ovaries, that is they were pale, small, and contained no enlarged follicles or corpora lutea, except in two cases in which there were much shrunken corpora lutea. There were no corpora albicantia though in some cases slight traces of scar tissue indicated sites of completely absorbed corpora lutea. Group 14 all exhibited a similar picture though the organs were of normal size.
Other less obvious deviations were observed. The membrana granulosa cells of large follicles in three animals showed the concentric chromatolysis, and chromato-lysis by margination described by Salazar (1919). This type of degeneration can easily be mistaken for polymorphonuclear invasion of the follicle, but is an indication of atresia. On the other hand, atresia is normally much more common in the smaller follicles, the usual fate of the follicle which reaches mature size being rupture and subsequent luteal transformation. Mitosis is rarely seen in the membrana granulosa of the ripe follicle (Brambell) but it was observed in several of these cases. Salazar discovered that sudden death or sideration of the nucleus usually set in during mitotic division, so this may perhaps indicate the first stage of the atretic change, preceding the chromatolysis described above. In the ovaries in all the groups save the last, i.e. in those killed up to 60 days from the start of treatment, some deviation from the normal was found.
The pituitary-gonadal relation is a mutual one, and the premature activity in-duced in the ovary of infantile mice by prolan may affect the pituitary so as to pre-vent it from exercising its gonadokinetic function for some time, either in whole or in part. This may afford a possible explanation of the small number of corpora lutea found after puberty, the infantile condition of the ovaries, and the atresia of large follicles. The differences found in the ovaries are explicable on the ground of normal variation of biological material.
SUMMARY.
The effects on the ovary of an amount of prolan just sufficient to produce ioo per cent, reaction in infantile mice may persist up to at least 60 days after administration. Blood points may be visible after 35 days. Many of the ovaries remained in the infantile state. It is suggested that this long duration effect may be explained by the reciprocal influence of the prematurely stimulated gonad on the pituitary.
A small number of adult mice similarly treated (16) showed relative sterility in comparison with a control group. They also exhibited some ovarian changes. Five to eight mouse units is probably about the minimal sterilising dose for mature animals.
Part of the expenses of this investigation were defrayed by a grant from the Earl of Moray Fund; Bayer Products kindly supplied the prolan used.
REFERENCES. BRAMBELL (1927). Proc. Roy. Soc. B, 101, 391.
KATZMAN (1932). Proc. Soc. Exp. Biol. and Med 29, 700. KENNEDY (1933). Quart. Journ. Exp. Physiol. 23, 367.
MANDELSTAMM and TSCHAIKOWSKY (1931). Zentralb.f. Gyn. 55, 3004. SALAZAR (1919). Mim. Soc. Portugaue da Set. Nat. Sir. Btol. No. 2, 1.
